A theoretical model for calculating the stress and strain states of cabling structures with different loadings has been developed in this paper. We solve the problem for the first- and second-stage cable with tensile ...A theoretical model for calculating the stress and strain states of cabling structures with different loadings has been developed in this paper. We solve the problem for the first- and second-stage cable with tensile or bending strain. The contact and friction forces between the strands are presented by two-dimensional contact model. Several theoretical models have been proposed to verify the results when the triplet subjected to the tensile strain, including contact force, contact stresses, and mechanical loss. It is found that loadings will affect the friction force and the mechanical loss of the triplet. The results show that the contact force and mechanical loss are dependent on the twist pitch. A shorter twist pitch can lead to higher contact force, while the trend of mechanical loss with twist pitch is complicated. The mechanical loss may be reduced by adjusting the twist pitch reasonably. The present model provides a simple analysis method to investigate the mechanical behaviors in multistage-structures under different loads.展开更多
The loss factors and their effects on the magnitude and frequency of resonance peaks in various mechanical sys-tems are reviewed for acoustic,vibration,and vibration fatigue applications.The main trends and relationsh...The loss factors and their effects on the magnitude and frequency of resonance peaks in various mechanical sys-tems are reviewed for acoustic,vibration,and vibration fatigue applications.The main trends and relationships were obtained for linear mechanical models with hysteresis damping.The well-known features(complex module of elasticity,total loss factor,etc.)are clarified for practical engineers and students,and new results are presented(in particular,for 2-DOF in-series models with hysteresis friction).The results are of both educational and prac-tical interest and may be applied for NVH analysis and testing,mechanical and aeromechanical design,and noise and vibration control in buildings.展开更多
A novel PCL/HA/TiO_(2)hybrid coating on ZM21 Mg alloy substrate has been investigated for corrosion resistance, biocompatibility and mechanical integrity loss in terms of bending, compressive and tensile strength in p...A novel PCL/HA/TiO_(2)hybrid coating on ZM21 Mg alloy substrate has been investigated for corrosion resistance, biocompatibility and mechanical integrity loss in terms of bending, compressive and tensile strength in physiological media. The prepared hybrid coating was dip coated over ZM21 from HA/TiO_(2)and PCL solutions followed by creating a microporous PCL layer by utilizing Non-solvent Induced Phase Separation(NIPS) technique. The electrochemical measurement and in-vitro degradation study in SBF after 28 days showed that the PCL/HA/TiO_(2) hybrid coating reduced H2 evolution rate, weight loss, and corrosion rate by 64, 116 and 118 times respectively, as compared to uncoated ZM21 samples. The surface studies carried out using SEM-EDX, FTIR and XRD revealed formation of highly stable 3d flower-like HA crystals with Ca/P ratio of 1.60 in the PCL micropores. This dense apatite growth effectively protected the PCL/HA/TiO_(2)hybrid coated samples to maintain the good mechanical integrity even after 28 days of immersion as compared to HA/TiO_(2)composite coated, As-polished(A/P) and As-machined(A/M) samples. The failure analysis of samples under mechanical loading were performed using SEM-BSE-EBSD.The in-vitro cellular viability of L929 fibroblast cells on PCL/HA/TiO_(2)hybrid coating was found 50.47% higher with respect to control group,whereas bacterial viability was supressed by 57.15 and 62.35% against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial models. The comprehensive assessment indicates PCL/HA/TiO_(2)hybrid coating as a suitable candidate to delay early degradation and mechanical integrity loss of Mg-based alloys for devising biodegradable orthopaedic implant.展开更多
Soil organic carbon(SOC)and total nitrogen(N)concentrations from bulk soils and soil particle size fractions in the different extent of desertified farmlands(potential, light, medium, severe, and most severe desertifi...Soil organic carbon(SOC)and total nitrogen(N)concentrations from bulk soils and soil particle size fractions in the different extent of desertified farmlands(potential, light, medium, severe, and most severe desertified farmlands)were examined to quantitatively elucidate losses of carbon and nitrogen and its mechanisms in the desertification process. Particle size fractions(2 -0.1 mm, 0.1 - 0.05 mm, <0.05 mm)were obtained by granulometric wet sieving from 30 sandy soils(0 - 15cm depth)of different desertified extent. It was shown that soil physical stability index(St)in most severe desertified farmlands was 5 -7% and St in other farmlands was less than 5 %, which contributed to very low soil organic matter content. This was the intrinsic cause that sandy farmlands in Horqin sandy land was subject to risk of desertification. Desertification resulted in considerable losses of SOC and N. Regression analysis indicated that SOC and N content reduced 0.169 g kg-1 and 0.0215 g kg-1 respectively with one percent loss of soil silt and clay content. Losses of SOC and N were mostly the removal of fine particle size fractions(silt and clay, and a less extent very fine sand)from the farmlands by wind erosion, which were rich in organic matter and nutrients, as well as the depletion of organic C and N associated with coarse particles(>0. 05 mm)in desertification process. The concentrations of C and N associated with sand(2 - 0.1 mm and 0.1 - 0.05 mm)significantly decreased with increase of desertified extent. Silt and clay associated C and N concentrations, however, were less changed, and in contrast, were higher in soils under most severe desertified extent than in soils under potential and severe desertified extent. The percentage of distribution in sand(>0.05 mm)associated C and N significantly increased with increase of desertified extent, suggesting that stability of SOC decreased in the desertification process.展开更多
The strength loss mechanism of the phosphate bonded sand mold/core was studied. The morphology and composition of phosphate membrane on the surface of sands was analyzed with electron probe X-ray microanalyzer. Result...The strength loss mechanism of the phosphate bonded sand mold/core was studied. The morphology and composition of phosphate membrane on the surface of sands was analyzed with electron probe X-ray microanalyzer. Results show that magnesium causes cracks in cured phosphate membrane and results in the decrease of sand molds/cores strength. However, the addition of magne-sium significantly enhanced hygroscopy resistance of phosphate membrane. In addition, the phosphate binder added with the magnesium modifier has more rapid hardening reaction speed compared that without or with low magnesium binder. It can be concluded that the phosphate binder with the addition of magnesium modifier is favorably used in high humid and cold circumstance.展开更多
The short season cotton(SSC) was important Upland plant ecotype(Gossypium hirsutum L.).The growth of SSC was very short that is 105 ～ 110 days(after planting). SSC could increase
Electrical energy can be harvested from the rotational kinetic energy of moving bodies,consisting of both mechanical and kinetic energy as a potential power source through electromagnetic induction,similar to wind ene...Electrical energy can be harvested from the rotational kinetic energy of moving bodies,consisting of both mechanical and kinetic energy as a potential power source through electromagnetic induction,similar to wind energy applications.In industries,rotational bodies are commonly present in operations,yet this kinetic energy remains untapped.This research explores the energy generation characteristics of two rotational body types,disk-shaped and cylinder-shaped under specific experimental setups.The hardware setup included a direct current(DC)motor driver,power supply,DC generator,mechanical support,and load resistance,while the software setup involved automation testing tools and data logging.Electromagnetic induction was used to harvest energy,and experiments were conducted at room temperature(25℃)with controlled variables like speed and friction.Results showed the disk-shaped body exhibited higher energy efficiency than the cylinder-shaped body,largely due to lower mechanical losses.The disk required only two bearings,while the cylinder required four,resulting in lower bearing losses for the disk.Additionally,the disk experienced only air friction,whereas the cylinder encountered friction from a soft,uneven rubber material,increasing surface contact losses.Under a 40 W resistive load,the disk demonstrated a 17.1%energy loss due to mechanical friction,achieving up to 15.55 J of recycled energy.Conversely,the cylinder body experienced a 48.05%energy loss,delivering only 51.95%of energy to the load.These insights suggest significant potential for designing efficient energy recycling systems in industrial settings,particularly in manufacturing and processing industries where rotational machinery is prevalent.Despite its lower energy density,this system could be beneficially integrated with energy storage solutions,enhancing sustainability in industrial practices.展开更多
Industrial processes often involve rotating machinery that generates substantial kinetic energy,much of which remains untapped.Harvesting rotational kinetic energy offers a promising solution to reduce energy waste an...Industrial processes often involve rotating machinery that generates substantial kinetic energy,much of which remains untapped.Harvesting rotational kinetic energy offers a promising solution to reduce energy waste and improve energy efficiency in industrial applications.This research investigates the potential of electromagnetic induction for harvesting rotational kinetic energy from industrial machinery.A comparative study was conducted between disk and cylinder-shaped rotational bodies to evaluate their energy efficiency under various load conditions.Experimental results demonstrated that the disk body exhibited higher energy efficiency,primarily due to lower mechanical losses compared to the cylinder body.A power management circuit was developed to regulate and store the harvested energy,integrating voltage,current,and speed sensors along with a charge controller for battery storage.The experimental setup successfully converted rotational kinetic energy into usable electrical power,with the disk achieving up to 16.33 J of recycled energy,outperforming the cylinder.The disk body demonstrated higher energy recovery efficiency compared to the cylinder,particularly under the 40 W resistive load condition.These findings demonstrate the feasibility of implementing energy recycling systems in industrial settings to enhance sustainability,reduce energy consumption,and minimize waste.Future research should focus on optimizing power management systems and improving energy harvesting efficiency to enable wider adoption of energy recycling technologies in various industrial applications.展开更多
The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and therm...The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and thermodynamic examination of Stirling engines,owing to their commendable model precision and remarkable efficiency.To scrutinize the effect of Stirling engine design parameters on the cyclical work output and efficiency,this study formulates a series of differential equations for the Stirling cycle by employing second-order analysis methods,subsequently augmenting the predictive accuracy by integrating considerations of loss mechanisms.In addition,an iterative method for the convergence of the average pressure was introduced.The predictive capability of the established model was validated using GPU-3 and RE-1000 experimental data.According to the model,parameters such as the operational fluid,porosity of the regenerator,and diameter of the wire mesh and their influence on the resulting work output and cyclic efficiency of the Stirling engine were analyzed,thereby facilitating a broader understanding of the engine's functional characteristics.These findings suggest that hydrogen,owing to its lower dynamic viscosity coefficient,can provide superior output power.The loss due to flow resistance tends to increase with the rotational speed.Additionally,under conditions of elevated rotational speed,the loss from flow resistance declines in cases of increased porosity,and the enhancement of the porosity to diminish flow resistance losses can boost both the output work and the cyclic efficiency of the engine.As the porosity increased further,the hydraulic diameter and dead volume in the regenerator continued to expand,causing the pressure drop within the engine to become the dominant factor in the gradual reduction of output power.Furthermore,extending the length of the regenerator results in a decrease in the output work,although the thermal cycle efficiency initially increases before eventually decreasing.Based on these insights,this study pursues the optimal designs for Stirling engines.展开更多
There is limited research reported on the multiple loss mechanism of electromagnetic waves(EMW)and the development of interface models.Dielectric loss and magnetic loss,as the two primary attenuation mechanisms in EMW...There is limited research reported on the multiple loss mechanism of electromagnetic waves(EMW)and the development of interface models.Dielectric loss and magnetic loss,as the two primary attenuation mechanisms in EMW absorbers,still pose challenges,especially in elucidating the correlation between composition,morphology,interface,and performance.Here,we construct 3D hierarchical porous conducting network structures and Schottky heterojunctions(MoNi_(4)@NC-NiFe_(2)O_(4)@NC)with a high density of defects,using trimetallic NiMoFe-MOFs.Synergistic enhancement of the dielectric and magnetic losses is realized through manipulation of the defects,interfaces,phase engineering,and magnetic resonance.In particular,the even dispersion of magnetic MoNi_(4) and NiFe_(2)O_(4)nanoparticles(NPs)within the carbon matrix triggers the creation of multiple heterogeneous interfaces.These inseparable interfaces,along with oxygen vacancies,play a role in enhancing dielectric polarization,while the closely spaced interactions among magnetic units contribute to magnetic loss.After optimizing the interfacial structure,NiFe_(2)O_(4)/MoNi_(4)-NC exhibits remarkable EMW absorption properties.A reflection loss(RL)value of-67.91 dB can be achieved at an ultra-thin thickness of 1.95 mm,and the effective absorption bandwidth(EAB,RL≤-10 dB)is as high as 5.76 GHz.Furthermore,we conducted radar scattering cross-section(RCS)simulations using computer simulation technology(CST)software,which revealed that NiFe_(2)O_(4)/MoNi_(4)-NC exhibits an RCS reduction value of 39.1 dB m^(2).Hence,this work provides comprehensive guidance for the construction of Schottky heterojunctions for lightweight EMW absorbers from a mechanistic point of view.展开更多
The composites prepared by combining lightweight carbon materials with magnetic metals have demonstrated excellent dielectric and magnetic properties,indicating potential applications in the field of electromagnetic w...The composites prepared by combining lightweight carbon materials with magnetic metals have demonstrated excellent dielectric and magnetic properties,indicating potential applications in the field of electromagnetic wave(EMW)absorption.However,the rational microstructure design and component optimization of these composites in regulating their magnetic-dielectric balance to achieve high-performance EMW absorption remains challenging.Herein,hierarchical yolk-shell Fe@SiO_(2)@NC composites with dual impedance matching layers and dual built-in electric fields were prepared by self-template aggregation and in situ reduction strategies.The introduction of a SiO_(2)wave-transparent layer into a conventional dielectric-magnetic system has resulted in the successful realization of nanoscale precise impedance matching regulation in absorbers,thereby enabling effective ultra-wideband EMW absorption.The dual impedance matching layers of the internal void layer and the SiO_(2)wave-transparent layer facilitate multiple scattering and reflection of EMWs within the absorbers,and the dual built-in electric fields of Fe/SiO_(2)and SiO_(2)/NC can effectively enhance interfacial polarization effect to attenuate EMWs.The predominantly optimized Fe@SiO_(2)@NC-2 exhibits an ultra-wide effective absorption bandwidth(EAB)of 7.10 GHz and an impressive minimum reflection loss(RL_(min))of−64.83 dB,indicating that optimizing the impedance matching via quantitative design can maximize the EMW absorption performance.This work provides a straightforward yet effective approach for constructing multi-component materials with hierarchical yolk-shell structure,which offers valuable insight into the microstructure design and component optimization of innovative EMW absorption materials.展开更多
In the long term,coal will remain a competitive resource in the thermal power sector,primarily due to its abundant global reserves and low costs.Despite numerous factors,including signifi cant environmental concerns,t...In the long term,coal will remain a competitive resource in the thermal power sector,primarily due to its abundant global reserves and low costs.Despite numerous factors,including signifi cant environmental concerns,the global share of coal power generation has remained at 40%over the past four decades.Effi cient and clean coal combustion is a high priority wherever coal is used as a fuel.An improved low-power boiler design has been proposed to enhance effi ciency during fi xedbed coal combustion.This design reduces harmful emissions into the atmosphere by optimizing parameters and operating modes.In this study,mathematical modeling of gas velocity and temperature distribution during fi xed-bed coal combustion was conducted for a conventional grate system and an improved grate-free system.Experimental methods were employed to develop descriptive airfl ow models in the fi xed coal layer,considering nozzle diameter and air supply pressure in the furnace chamber without a grate system.Comparative evaluations of fi xed-bed coal combustion rates were performed using an experimental laboratory setup with both grate and grate-free stove systems.展开更多
Rubber has strong nonlinear viscoelastic characteristic. Under effect of the periodically changing external force,it will show the phenomenon of lagging deformation and mechanical loss,which means deformation lags beh...Rubber has strong nonlinear viscoelastic characteristic. Under effect of the periodically changing external force,it will show the phenomenon of lagging deformation and mechanical loss,which means deformation lags behind stress changes and the situation of loss of work is caused by the hysteresis. Loss of work will be transformed into thermal energy and makes the temperature of rubber and the object in contact with it rise,which will thereby affect the dynamic characteristics of the structure. Based on a pair of mutual rotating and squeezing steel-rubber rollers as the research object,the finite element simulation software Ansys is used in this paper to analyze the temperature field of the structure. As a result,temperature distribution characteristics of two directions are obtained. One is squeezing area along the direction of the wall,the other is along the direction of thickness of rubber. Then the influence of the rotating speed and the pressure between two rollers on temperature of rubber is analyzed. The temperature experiment of mutual squeezing contact steelrubber roller is carried out on the experimental platform via using infrared thermal imager and infrared thermometer. The experiment data are in accordance with the simulation results on regulation of temperature distribution as well as high degree of similarity on value,which shows the effectiveness of simulation. Research results are of great significance for temperature characteristic analysis of rubber structure.展开更多
The calculation of the mechanical energy loss is one of the fundamental problems in the field of Hydraulics and Engineering Fluid Mechanics. However, for a non-uniform flow the relation between the mechanical energy l...The calculation of the mechanical energy loss is one of the fundamental problems in the field of Hydraulics and Engineering Fluid Mechanics. However, for a non-uniform flow the relation between the mechanical energy loss in a volume of fluid and the kinematical and dynamical characteristics of the flow field is not clearly established. In this paper a new mechanical energy equation for the incompressible steady non-uniform pipe flow of homogeneous fluid is derived, which includes the variation of the mean turbulent kinetic energy, and the formula for the calculation of the mechanical energy transformation loss for the non-uniform flow between two cross sections is obtained based on this equation. This formula can be simplified to the Darcy-Weisbach formula for the uniform flow as widely used in Hydraulics. Furthermore, the contributions of the mechanical energy loss relative to the time averaged velocity gradient and the dissipation of the turbulent kinetic energy in the turbulent uniform pipe flow are discussed, and the contributions of the mechanical energy loss in the viscous sublayer, the buffer layer and the region above the buffer layer for the turbulent uniform flow are also analyzed.展开更多
Ingenious microstructure design and rational composition collocation have been proved to be an effective strategy for developing efficient electromagnetic wave(EMW)absorbers.It would be promising to fabricate a hollow...Ingenious microstructure design and rational composition collocation have been proved to be an effective strategy for developing efficient electromagnetic wave(EMW)absorbers.It would be promising to fabricate a hollow structured composite integrating multiple loss mechanisms(conduction,magnetic,and polarization losses)for excellent EMW absorption.Herein,a novel dielectric-magnetic compound of ZnO/Ni@C hollow microsphere was prepared through hydrothermal reactions followed by an in-situ chemical vapor deposition(CVD).In this ternary composite,abundant ZnO/Ni heterostructures formed the hollow microsphere skeletons and provided unique Schottky junctions,which endowed the composite with improved impedance matching and strong polarization loss.Meanwhile,the amorphouspolycrystalline carbon layer deposited on the surface of each microsphere enhanced the conduction and interfacial polarization losses.In addition,the magnetic Ni nanoparticles induced magnetic loss.Benefiting from the synergistic effect of the hollow structure and multiple loss mechanisms,the ternary composite exhibits an effective absorption bandwidth as wide as 6.55 GHz at a thickness of only 1.85 mm,accompanied by a minimum reflection loss of–39.8 dB.Besides,the radar cross-section and the electromagnetic field simulation further verify the superior EMW absorption performance of the composites.Our work provides a new reference for the fabrication of dielectric-magnetic ternary hollow microspheres as EMW absorbers with thin thickness and broad bandwidth.展开更多
The mechanical energy loss and the wall resistance are very important in practical engineering. These problems are investigated through theoretical analysis and numerical simulation in this paper, The results are as f...The mechanical energy loss and the wall resistance are very important in practical engineering. These problems are investigated through theoretical analysis and numerical simulation in this paper, The results are as follows. （1） A new mechanical energy equation for the total flow is obtained, and a general formula for the calculation of the mechanical energy loss is proposed. （2） The general relationship between the wall resistance and the mechanical energy loss for the steady channel flow is obtained, the simplified form of which for the steady uniform channel flow is in consistent with the formula used in Hydraulics deduced by 7r theorem and dimensional analysis. （3） The steady channel flow over a backward facing step with a small expansion ratio is numerica- lly simulated, and the mechanical energy loss, the wall resistance as well as the relationship between the wall resistance and the mechanical energy loss are calculated and analyzed.展开更多
A new type of composite filler was designed by a modified sol-gel method using fly ash(FA),Fe(NO_(3))_(3)·9H_(2)O,and Ni(NO_(3))_(2)·6H_(2)O as raw materials.The composite filler was a spherical core-shell s...A new type of composite filler was designed by a modified sol-gel method using fly ash(FA),Fe(NO_(3))_(3)·9H_(2)O,and Ni(NO_(3))_(2)·6H_(2)O as raw materials.The composite filler was a spherical core-shell structure composed of FA as the core and NiFe_(2)O_(4)as the shell.Further,the composite filler was added into the silicone rubber to fabricate the high temperature vulcanized microwave absorption materials;X-ray diffraction,fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,and scanning electron microscope confirmed that NiFe_(2)O_(4)was successfully coated on the surface of FA and formed a uniform and continuous coating layer.As expected,silicone rubber filled with the composite filler had a minimum reflection loss of-23.8 dB at 17.5 GHz with the thickness of 1.8 mm,while the effective absorption bandwidth was as high as 12 GHz.The addition of the composite filler greatly enhanced the microwave absorption properties of the system,which was resulted from multiple losses mechanism:interface polarization losses,magnetic losses,and multiple reflection losses.Also,silicone rubber filled with the composite filler exhibited excellent thermal stability,flexibility,environmental resistance,and hydrophobicity compared with traditional silicone rubber.Therefore,this work not only responds to the green chemistry to achieve efficient FA recovery,but also devises a new strategy to prepare microwave absorption materials with strong potential for civilian applications.展开更多
According to the statistics of cultivated land in Yantai area during the Reform and Opening-up over the past 20 years and with the detailed survey and changing data of land use during the recent live years, this paper...According to the statistics of cultivated land in Yantai area during the Reform and Opening-up over the past 20 years and with the detailed survey and changing data of land use during the recent live years, this paper reveals the basic characteristics of the resource utilization, the basic process of the changes, regional differences, and current direction of cultivated land In addition, this paper makes a preliminary research on the major driving factors and the influence mechanism for the changes in the cultivated land area. and reaches the following conclasions： （1） There was a trend of obvious fluctuant decrease in cultivated laud area during the past 20 years. The changes of cultivated land have undergone the process - slow decrease,steep decrease, slow decrease. And there were three peak periods of cultivated land loss around 1985. 1987-1996 and 1991-1993 respectively （2） The decreased cultivated land was mainly converted into land for industry and mining, residential area. and all kinds of traffic and orchards. The increase of cultivated land mainly came from exploitation and land and arrangement and reclamation of industry and mining land （3） The economic development. population growth and policy are the dominant macro-driving factors for the decrease of cultivated land area in Yantai. The obvious sudden changes during the change process of cultivated land acreage are relevant to the national macro.policies background The rapid decrease of cnltivated land area is synchronous with the overheated economic growth resulting from the direct investment in fixed assets. Spatial distribution of the decrease in cultivated land is congruous with the differences in speed and the scale of economic growth between the different regions of Yantai area. Furthermore. the decrease in cultivated land caused by population increase cannot be ignored.展开更多
The demand and pursuit of chemical entities with UV filtration and antioxidant properties for enhanced photoprotection have been driven in recent times by acute exposure of humans to solar ultraviolet radiations. The ...The demand and pursuit of chemical entities with UV filtration and antioxidant properties for enhanced photoprotection have been driven in recent times by acute exposure of humans to solar ultraviolet radiations. The structural, electronic, antioxidant and UV absorption properties of drometrizole (PBT) and designed ortho-substituted derivatives are reported via DFT and TD-DFT in the gas and aqueous phases. DFT and TD-DFT computations were performed at the M062x-D3Zero/6-311++G(d,p)//B97-3c and PBE0-D3(BJ)/def2-TZVP levels of theory respectively. Reaction enthalpies related to hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET) mechanisms were computed and compared with those of phenol. Results show that the presence of -NH2 substituent reduces the O-H bond dissociation enthalpy and ionization potential, while that of -CN increases the proton affinity. The HAT and SPLET mechanisms are the most plausible in the gas and aqueous phases respectively. The molecule with the -NH2 substituent (PBT1) was identified to be the compound with the highest antioxidant activity. The UV spectra of the studied compounds are characterized by two bands in the 280 - 400 nm regions. Results from this study provide a better comprehension antioxidant mechanism of drometrizole and present a new perspective for the design of electron-donor antioxidant molecules with enhanced antioxidant-photoprotective efficiencies for applications in commercial sunscreens.展开更多
A loss model for the mixed-flow pump impellers was developed by summarizing a variety of loss calculation formulas systematically.The internal flow field of the impeller was obtained by employing the iterative calcula...A loss model for the mixed-flow pump impellers was developed by summarizing a variety of loss calculation formulas systematically.The internal flow field of the impeller was obtained by employing the iterative calculation for S 1 and S 2 stream surfaces to solve the continuity and motion equations of fluid.Based on the calculation method of the flow field and the loss model,it is achieved to predict the impeller performance of the mixed-flow pump and the performance curves of a mixed-flow pump model with adjustable blades.Compared with the test data,the loss model of the mixed-flow pump based on the iterative calculation can predict the impeller performance quickly and accurately,which has a high value on the engineering applications.Based on the test verification,curves of various kinds of losses varied for the flow rate were analyzed under different blade angles.In addition,the mechanisms of various kinds of losses inside the mixed-flow pump impeller were discussed in-depth.展开更多
基金supported by National Natural Science Foundation of China (Grants 11202087, 11472120, 11421062)the National Key Project of Scientific Instrument and Equipment Development (Grant 11327802)+1 种基金the National Key Project of Magneto-Constrained Fusion Energy Development Program (Grant 2013GB110002)New Century Excellent Talents in University of Ministry of Education of China (Grant NCET-13-0266)
文摘A theoretical model for calculating the stress and strain states of cabling structures with different loadings has been developed in this paper. We solve the problem for the first- and second-stage cable with tensile or bending strain. The contact and friction forces between the strands are presented by two-dimensional contact model. Several theoretical models have been proposed to verify the results when the triplet subjected to the tensile strain, including contact force, contact stresses, and mechanical loss. It is found that loadings will affect the friction force and the mechanical loss of the triplet. The results show that the contact force and mechanical loss are dependent on the twist pitch. A shorter twist pitch can lead to higher contact force, while the trend of mechanical loss with twist pitch is complicated. The mechanical loss may be reduced by adjusting the twist pitch reasonably. The present model provides a simple analysis method to investigate the mechanical behaviors in multistage-structures under different loads.
文摘The loss factors and their effects on the magnitude and frequency of resonance peaks in various mechanical sys-tems are reviewed for acoustic,vibration,and vibration fatigue applications.The main trends and relationships were obtained for linear mechanical models with hysteresis damping.The well-known features(complex module of elasticity,total loss factor,etc.)are clarified for practical engineers and students,and new results are presented(in particular,for 2-DOF in-series models with hysteresis friction).The results are of both educational and prac-tical interest and may be applied for NVH analysis and testing,mechanical and aeromechanical design,and noise and vibration control in buildings.
基金CSIR-IMTECH laboratory for providing the technical support in biocompatibility testing。
文摘A novel PCL/HA/TiO_(2)hybrid coating on ZM21 Mg alloy substrate has been investigated for corrosion resistance, biocompatibility and mechanical integrity loss in terms of bending, compressive and tensile strength in physiological media. The prepared hybrid coating was dip coated over ZM21 from HA/TiO_(2)and PCL solutions followed by creating a microporous PCL layer by utilizing Non-solvent Induced Phase Separation(NIPS) technique. The electrochemical measurement and in-vitro degradation study in SBF after 28 days showed that the PCL/HA/TiO_(2) hybrid coating reduced H2 evolution rate, weight loss, and corrosion rate by 64, 116 and 118 times respectively, as compared to uncoated ZM21 samples. The surface studies carried out using SEM-EDX, FTIR and XRD revealed formation of highly stable 3d flower-like HA crystals with Ca/P ratio of 1.60 in the PCL micropores. This dense apatite growth effectively protected the PCL/HA/TiO_(2)hybrid coated samples to maintain the good mechanical integrity even after 28 days of immersion as compared to HA/TiO_(2)composite coated, As-polished(A/P) and As-machined(A/M) samples. The failure analysis of samples under mechanical loading were performed using SEM-BSE-EBSD.The in-vitro cellular viability of L929 fibroblast cells on PCL/HA/TiO_(2)hybrid coating was found 50.47% higher with respect to control group,whereas bacterial viability was supressed by 57.15 and 62.35% against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial models. The comprehensive assessment indicates PCL/HA/TiO_(2)hybrid coating as a suitable candidate to delay early degradation and mechanical integrity loss of Mg-based alloys for devising biodegradable orthopaedic implant.
文摘Soil organic carbon(SOC)and total nitrogen(N)concentrations from bulk soils and soil particle size fractions in the different extent of desertified farmlands(potential, light, medium, severe, and most severe desertified farmlands)were examined to quantitatively elucidate losses of carbon and nitrogen and its mechanisms in the desertification process. Particle size fractions(2 -0.1 mm, 0.1 - 0.05 mm, <0.05 mm)were obtained by granulometric wet sieving from 30 sandy soils(0 - 15cm depth)of different desertified extent. It was shown that soil physical stability index(St)in most severe desertified farmlands was 5 -7% and St in other farmlands was less than 5 %, which contributed to very low soil organic matter content. This was the intrinsic cause that sandy farmlands in Horqin sandy land was subject to risk of desertification. Desertification resulted in considerable losses of SOC and N. Regression analysis indicated that SOC and N content reduced 0.169 g kg-1 and 0.0215 g kg-1 respectively with one percent loss of soil silt and clay content. Losses of SOC and N were mostly the removal of fine particle size fractions(silt and clay, and a less extent very fine sand)from the farmlands by wind erosion, which were rich in organic matter and nutrients, as well as the depletion of organic C and N associated with coarse particles(>0. 05 mm)in desertification process. The concentrations of C and N associated with sand(2 - 0.1 mm and 0.1 - 0.05 mm)significantly decreased with increase of desertified extent. Silt and clay associated C and N concentrations, however, were less changed, and in contrast, were higher in soils under most severe desertified extent than in soils under potential and severe desertified extent. The percentage of distribution in sand(>0.05 mm)associated C and N significantly increased with increase of desertified extent, suggesting that stability of SOC decreased in the desertification process.
基金Funded by the Natural Science Foundation of Hubei Province (No. 2005ABA056)
文摘The strength loss mechanism of the phosphate bonded sand mold/core was studied. The morphology and composition of phosphate membrane on the surface of sands was analyzed with electron probe X-ray microanalyzer. Results show that magnesium causes cracks in cured phosphate membrane and results in the decrease of sand molds/cores strength. However, the addition of magne-sium significantly enhanced hygroscopy resistance of phosphate membrane. In addition, the phosphate binder added with the magnesium modifier has more rapid hardening reaction speed compared that without or with low magnesium binder. It can be concluded that the phosphate binder with the addition of magnesium modifier is favorably used in high humid and cold circumstance.
文摘The short season cotton(SSC) was important Upland plant ecotype(Gossypium hirsutum L.).The growth of SSC was very short that is 105 ～ 110 days(after planting). SSC could increase
基金The APC was funded by Research Management Center, Multimedia University, Malaysia.
文摘Electrical energy can be harvested from the rotational kinetic energy of moving bodies,consisting of both mechanical and kinetic energy as a potential power source through electromagnetic induction,similar to wind energy applications.In industries,rotational bodies are commonly present in operations,yet this kinetic energy remains untapped.This research explores the energy generation characteristics of two rotational body types,disk-shaped and cylinder-shaped under specific experimental setups.The hardware setup included a direct current(DC)motor driver,power supply,DC generator,mechanical support,and load resistance,while the software setup involved automation testing tools and data logging.Electromagnetic induction was used to harvest energy,and experiments were conducted at room temperature(25℃)with controlled variables like speed and friction.Results showed the disk-shaped body exhibited higher energy efficiency than the cylinder-shaped body,largely due to lower mechanical losses.The disk required only two bearings,while the cylinder required four,resulting in lower bearing losses for the disk.Additionally,the disk experienced only air friction,whereas the cylinder encountered friction from a soft,uneven rubber material,increasing surface contact losses.Under a 40 W resistive load,the disk demonstrated a 17.1%energy loss due to mechanical friction,achieving up to 15.55 J of recycled energy.Conversely,the cylinder body experienced a 48.05%energy loss,delivering only 51.95%of energy to the load.These insights suggest significant potential for designing efficient energy recycling systems in industrial settings,particularly in manufacturing and processing industries where rotational machinery is prevalent.Despite its lower energy density,this system could be beneficially integrated with energy storage solutions,enhancing sustainability in industrial practices.
文摘Industrial processes often involve rotating machinery that generates substantial kinetic energy,much of which remains untapped.Harvesting rotational kinetic energy offers a promising solution to reduce energy waste and improve energy efficiency in industrial applications.This research investigates the potential of electromagnetic induction for harvesting rotational kinetic energy from industrial machinery.A comparative study was conducted between disk and cylinder-shaped rotational bodies to evaluate their energy efficiency under various load conditions.Experimental results demonstrated that the disk body exhibited higher energy efficiency,primarily due to lower mechanical losses compared to the cylinder body.A power management circuit was developed to regulate and store the harvested energy,integrating voltage,current,and speed sensors along with a charge controller for battery storage.The experimental setup successfully converted rotational kinetic energy into usable electrical power,with the disk achieving up to 16.33 J of recycled energy,outperforming the cylinder.The disk body demonstrated higher energy recovery efficiency compared to the cylinder,particularly under the 40 W resistive load condition.These findings demonstrate the feasibility of implementing energy recycling systems in industrial settings to enhance sustainability,reduce energy consumption,and minimize waste.Future research should focus on optimizing power management systems and improving energy harvesting efficiency to enable wider adoption of energy recycling technologies in various industrial applications.
基金supported by Sichuan Science and Technology Program(No.24NSFSC4579)National Natural Science Foundation of China(No.12305193)+2 种基金Sichuan Science and Technology Program(No.23NSFSC6149)National Natural Science Foundation of China(No.12305194)Technology on Reactor System Design Technology Laboratory Stable support Funding(No.2023_JCJQ_LB_003).
文摘The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and thermodynamic examination of Stirling engines,owing to their commendable model precision and remarkable efficiency.To scrutinize the effect of Stirling engine design parameters on the cyclical work output and efficiency,this study formulates a series of differential equations for the Stirling cycle by employing second-order analysis methods,subsequently augmenting the predictive accuracy by integrating considerations of loss mechanisms.In addition,an iterative method for the convergence of the average pressure was introduced.The predictive capability of the established model was validated using GPU-3 and RE-1000 experimental data.According to the model,parameters such as the operational fluid,porosity of the regenerator,and diameter of the wire mesh and their influence on the resulting work output and cyclic efficiency of the Stirling engine were analyzed,thereby facilitating a broader understanding of the engine's functional characteristics.These findings suggest that hydrogen,owing to its lower dynamic viscosity coefficient,can provide superior output power.The loss due to flow resistance tends to increase with the rotational speed.Additionally,under conditions of elevated rotational speed,the loss from flow resistance declines in cases of increased porosity,and the enhancement of the porosity to diminish flow resistance losses can boost both the output work and the cyclic efficiency of the engine.As the porosity increased further,the hydraulic diameter and dead volume in the regenerator continued to expand,causing the pressure drop within the engine to become the dominant factor in the gradual reduction of output power.Furthermore,extending the length of the regenerator results in a decrease in the output work,although the thermal cycle efficiency initially increases before eventually decreasing.Based on these insights,this study pursues the optimal designs for Stirling engines.
基金supported by the National Natural Science Foundation of China(No.22269010)the Jiangxi Provincial Natural Science Foundation(No.20224BAB214021).
文摘There is limited research reported on the multiple loss mechanism of electromagnetic waves(EMW)and the development of interface models.Dielectric loss and magnetic loss,as the two primary attenuation mechanisms in EMW absorbers,still pose challenges,especially in elucidating the correlation between composition,morphology,interface,and performance.Here,we construct 3D hierarchical porous conducting network structures and Schottky heterojunctions(MoNi_(4)@NC-NiFe_(2)O_(4)@NC)with a high density of defects,using trimetallic NiMoFe-MOFs.Synergistic enhancement of the dielectric and magnetic losses is realized through manipulation of the defects,interfaces,phase engineering,and magnetic resonance.In particular,the even dispersion of magnetic MoNi_(4) and NiFe_(2)O_(4)nanoparticles(NPs)within the carbon matrix triggers the creation of multiple heterogeneous interfaces.These inseparable interfaces,along with oxygen vacancies,play a role in enhancing dielectric polarization,while the closely spaced interactions among magnetic units contribute to magnetic loss.After optimizing the interfacial structure,NiFe_(2)O_(4)/MoNi_(4)-NC exhibits remarkable EMW absorption properties.A reflection loss(RL)value of-67.91 dB can be achieved at an ultra-thin thickness of 1.95 mm,and the effective absorption bandwidth(EAB,RL≤-10 dB)is as high as 5.76 GHz.Furthermore,we conducted radar scattering cross-section(RCS)simulations using computer simulation technology(CST)software,which revealed that NiFe_(2)O_(4)/MoNi_(4)-NC exhibits an RCS reduction value of 39.1 dB m^(2).Hence,this work provides comprehensive guidance for the construction of Schottky heterojunctions for lightweight EMW absorbers from a mechanistic point of view.
基金financially supported by the National Natural Science Foundation of China(Nos.52172222 and 51972226)the National Natural Science Foundation of Tianjin City(No.20JCZDJC00570).
文摘The composites prepared by combining lightweight carbon materials with magnetic metals have demonstrated excellent dielectric and magnetic properties,indicating potential applications in the field of electromagnetic wave(EMW)absorption.However,the rational microstructure design and component optimization of these composites in regulating their magnetic-dielectric balance to achieve high-performance EMW absorption remains challenging.Herein,hierarchical yolk-shell Fe@SiO_(2)@NC composites with dual impedance matching layers and dual built-in electric fields were prepared by self-template aggregation and in situ reduction strategies.The introduction of a SiO_(2)wave-transparent layer into a conventional dielectric-magnetic system has resulted in the successful realization of nanoscale precise impedance matching regulation in absorbers,thereby enabling effective ultra-wideband EMW absorption.The dual impedance matching layers of the internal void layer and the SiO_(2)wave-transparent layer facilitate multiple scattering and reflection of EMWs within the absorbers,and the dual built-in electric fields of Fe/SiO_(2)and SiO_(2)/NC can effectively enhance interfacial polarization effect to attenuate EMWs.The predominantly optimized Fe@SiO_(2)@NC-2 exhibits an ultra-wide effective absorption bandwidth(EAB)of 7.10 GHz and an impressive minimum reflection loss(RL_(min))of−64.83 dB,indicating that optimizing the impedance matching via quantitative design can maximize the EMW absorption performance.This work provides a straightforward yet effective approach for constructing multi-component materials with hierarchical yolk-shell structure,which offers valuable insight into the microstructure design and component optimization of innovative EMW absorption materials.
基金The Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan(No.AP19679995)have funded this research.
文摘In the long term,coal will remain a competitive resource in the thermal power sector,primarily due to its abundant global reserves and low costs.Despite numerous factors,including signifi cant environmental concerns,the global share of coal power generation has remained at 40%over the past four decades.Effi cient and clean coal combustion is a high priority wherever coal is used as a fuel.An improved low-power boiler design has been proposed to enhance effi ciency during fi xedbed coal combustion.This design reduces harmful emissions into the atmosphere by optimizing parameters and operating modes.In this study,mathematical modeling of gas velocity and temperature distribution during fi xed-bed coal combustion was conducted for a conventional grate system and an improved grate-free system.Experimental methods were employed to develop descriptive airfl ow models in the fi xed coal layer,considering nozzle diameter and air supply pressure in the furnace chamber without a grate system.Comparative evaluations of fi xed-bed coal combustion rates were performed using an experimental laboratory setup with both grate and grate-free stove systems.
基金Supported by the National Natural Science Foundation of China(No.51675010)Science Technology Project of Beijing Municipal Education Commission(KM201710005015)
文摘Rubber has strong nonlinear viscoelastic characteristic. Under effect of the periodically changing external force,it will show the phenomenon of lagging deformation and mechanical loss,which means deformation lags behind stress changes and the situation of loss of work is caused by the hysteresis. Loss of work will be transformed into thermal energy and makes the temperature of rubber and the object in contact with it rise,which will thereby affect the dynamic characteristics of the structure. Based on a pair of mutual rotating and squeezing steel-rubber rollers as the research object,the finite element simulation software Ansys is used in this paper to analyze the temperature field of the structure. As a result,temperature distribution characteristics of two directions are obtained. One is squeezing area along the direction of the wall,the other is along the direction of thickness of rubber. Then the influence of the rotating speed and the pressure between two rollers on temperature of rubber is analyzed. The temperature experiment of mutual squeezing contact steelrubber roller is carried out on the experimental platform via using infrared thermal imager and infrared thermometer. The experiment data are in accordance with the simulation results on regulation of temperature distribution as well as high degree of similarity on value,which shows the effectiveness of simulation. Research results are of great significance for temperature characteristic analysis of rubber structure.
文摘The calculation of the mechanical energy loss is one of the fundamental problems in the field of Hydraulics and Engineering Fluid Mechanics. However, for a non-uniform flow the relation between the mechanical energy loss in a volume of fluid and the kinematical and dynamical characteristics of the flow field is not clearly established. In this paper a new mechanical energy equation for the incompressible steady non-uniform pipe flow of homogeneous fluid is derived, which includes the variation of the mean turbulent kinetic energy, and the formula for the calculation of the mechanical energy transformation loss for the non-uniform flow between two cross sections is obtained based on this equation. This formula can be simplified to the Darcy-Weisbach formula for the uniform flow as widely used in Hydraulics. Furthermore, the contributions of the mechanical energy loss relative to the time averaged velocity gradient and the dissipation of the turbulent kinetic energy in the turbulent uniform pipe flow are discussed, and the contributions of the mechanical energy loss in the viscous sublayer, the buffer layer and the region above the buffer layer for the turbulent uniform flow are also analyzed.
基金supported by the National Natural Science Foundation of China(Nos.52272288 and 51972039)the China Postdoctoral Science Foundation(No.2021M700658).
文摘Ingenious microstructure design and rational composition collocation have been proved to be an effective strategy for developing efficient electromagnetic wave(EMW)absorbers.It would be promising to fabricate a hollow structured composite integrating multiple loss mechanisms(conduction,magnetic,and polarization losses)for excellent EMW absorption.Herein,a novel dielectric-magnetic compound of ZnO/Ni@C hollow microsphere was prepared through hydrothermal reactions followed by an in-situ chemical vapor deposition(CVD).In this ternary composite,abundant ZnO/Ni heterostructures formed the hollow microsphere skeletons and provided unique Schottky junctions,which endowed the composite with improved impedance matching and strong polarization loss.Meanwhile,the amorphouspolycrystalline carbon layer deposited on the surface of each microsphere enhanced the conduction and interfacial polarization losses.In addition,the magnetic Ni nanoparticles induced magnetic loss.Benefiting from the synergistic effect of the hollow structure and multiple loss mechanisms,the ternary composite exhibits an effective absorption bandwidth as wide as 6.55 GHz at a thickness of only 1.85 mm,accompanied by a minimum reflection loss of–39.8 dB.Besides,the radar cross-section and the electromagnetic field simulation further verify the superior EMW absorption performance of the composites.Our work provides a new reference for the fabrication of dielectric-magnetic ternary hollow microspheres as EMW absorbers with thin thickness and broad bandwidth.
文摘The mechanical energy loss and the wall resistance are very important in practical engineering. These problems are investigated through theoretical analysis and numerical simulation in this paper, The results are as follows. （1） A new mechanical energy equation for the total flow is obtained, and a general formula for the calculation of the mechanical energy loss is proposed. （2） The general relationship between the wall resistance and the mechanical energy loss for the steady channel flow is obtained, the simplified form of which for the steady uniform channel flow is in consistent with the formula used in Hydraulics deduced by 7r theorem and dimensional analysis. （3） The steady channel flow over a backward facing step with a small expansion ratio is numerica- lly simulated, and the mechanical energy loss, the wall resistance as well as the relationship between the wall resistance and the mechanical energy loss are calculated and analyzed.
文摘A new type of composite filler was designed by a modified sol-gel method using fly ash(FA),Fe(NO_(3))_(3)·9H_(2)O,and Ni(NO_(3))_(2)·6H_(2)O as raw materials.The composite filler was a spherical core-shell structure composed of FA as the core and NiFe_(2)O_(4)as the shell.Further,the composite filler was added into the silicone rubber to fabricate the high temperature vulcanized microwave absorption materials;X-ray diffraction,fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,and scanning electron microscope confirmed that NiFe_(2)O_(4)was successfully coated on the surface of FA and formed a uniform and continuous coating layer.As expected,silicone rubber filled with the composite filler had a minimum reflection loss of-23.8 dB at 17.5 GHz with the thickness of 1.8 mm,while the effective absorption bandwidth was as high as 12 GHz.The addition of the composite filler greatly enhanced the microwave absorption properties of the system,which was resulted from multiple losses mechanism:interface polarization losses,magnetic losses,and multiple reflection losses.Also,silicone rubber filled with the composite filler exhibited excellent thermal stability,flexibility,environmental resistance,and hydrophobicity compared with traditional silicone rubber.Therefore,this work not only responds to the green chemistry to achieve efficient FA recovery,but also devises a new strategy to prepare microwave absorption materials with strong potential for civilian applications.
基金Supported by National Natural Science Foundation of China (40101005), Natural Science Foundation of Shandong Province (Q2002E03), and Education Department Foundation of ShandongProvince (J02L01).
文摘According to the statistics of cultivated land in Yantai area during the Reform and Opening-up over the past 20 years and with the detailed survey and changing data of land use during the recent live years, this paper reveals the basic characteristics of the resource utilization, the basic process of the changes, regional differences, and current direction of cultivated land In addition, this paper makes a preliminary research on the major driving factors and the influence mechanism for the changes in the cultivated land area. and reaches the following conclasions： （1） There was a trend of obvious fluctuant decrease in cultivated laud area during the past 20 years. The changes of cultivated land have undergone the process - slow decrease,steep decrease, slow decrease. And there were three peak periods of cultivated land loss around 1985. 1987-1996 and 1991-1993 respectively （2） The decreased cultivated land was mainly converted into land for industry and mining, residential area. and all kinds of traffic and orchards. The increase of cultivated land mainly came from exploitation and land and arrangement and reclamation of industry and mining land （3） The economic development. population growth and policy are the dominant macro-driving factors for the decrease of cultivated land area in Yantai. The obvious sudden changes during the change process of cultivated land acreage are relevant to the national macro.policies background The rapid decrease of cnltivated land area is synchronous with the overheated economic growth resulting from the direct investment in fixed assets. Spatial distribution of the decrease in cultivated land is congruous with the differences in speed and the scale of economic growth between the different regions of Yantai area. Furthermore. the decrease in cultivated land caused by population increase cannot be ignored.
文摘The demand and pursuit of chemical entities with UV filtration and antioxidant properties for enhanced photoprotection have been driven in recent times by acute exposure of humans to solar ultraviolet radiations. The structural, electronic, antioxidant and UV absorption properties of drometrizole (PBT) and designed ortho-substituted derivatives are reported via DFT and TD-DFT in the gas and aqueous phases. DFT and TD-DFT computations were performed at the M062x-D3Zero/6-311++G(d,p)//B97-3c and PBE0-D3(BJ)/def2-TZVP levels of theory respectively. Reaction enthalpies related to hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET) mechanisms were computed and compared with those of phenol. Results show that the presence of -NH2 substituent reduces the O-H bond dissociation enthalpy and ionization potential, while that of -CN increases the proton affinity. The HAT and SPLET mechanisms are the most plausible in the gas and aqueous phases respectively. The molecule with the -NH2 substituent (PBT1) was identified to be the compound with the highest antioxidant activity. The UV spectra of the studied compounds are characterized by two bands in the 280 - 400 nm regions. Results from this study provide a better comprehension antioxidant mechanism of drometrizole and present a new perspective for the design of electron-donor antioxidant molecules with enhanced antioxidant-photoprotective efficiencies for applications in commercial sunscreens.
基金supported by the National Natural Science Foundation of China (Grant No. 51176088)the Open Research Foundation of State Key Laboratory of Hydroscience and Engineering of Tsinghua University(Grant No. 2009T3)
文摘A loss model for the mixed-flow pump impellers was developed by summarizing a variety of loss calculation formulas systematically.The internal flow field of the impeller was obtained by employing the iterative calculation for S 1 and S 2 stream surfaces to solve the continuity and motion equations of fluid.Based on the calculation method of the flow field and the loss model,it is achieved to predict the impeller performance of the mixed-flow pump and the performance curves of a mixed-flow pump model with adjustable blades.Compared with the test data,the loss model of the mixed-flow pump based on the iterative calculation can predict the impeller performance quickly and accurately,which has a high value on the engineering applications.Based on the test verification,curves of various kinds of losses varied for the flow rate were analyzed under different blade angles.In addition,the mechanisms of various kinds of losses inside the mixed-flow pump impeller were discussed in-depth.
