The Electro–Hydrostatic Actuator(EHA)is applied to drive the control surface in flightcontrol system of more electric aircraft.In EHA,the Oil-Immersed Motor Pump(OMP)serves asthe core as a power assembly.However,the ...The Electro–Hydrostatic Actuator(EHA)is applied to drive the control surface in flightcontrol system of more electric aircraft.In EHA,the Oil-Immersed Motor Pump(OMP)serves asthe core as a power assembly.However,the compact integration of the OMP presents challenges inefficiently dissipating internal heat,leading to a performance degradation of the EHA due to ele-vated temperatures.Therefore,accurately modeling and predicting the internal thermal dynamicsof the OMP hold considerable significance for monitoring the operational condition of the EHA.In view of this,a modeling method considering cumulative thermal coupling was hereby proposed.Based on the proposed method,the thermal models of the motor and the pump were established,taking into account heat accumulation and transfer.Taking the leakage oil as the heat couplingpoint between the motor and the pump,the dynamic thermal coupling model of the OMP wasdeveloped,with the thermal characteristics of the oil considered.Additionally,the comparativeexperiments were conducted to illustrate the efficiency of the proposed model.The experimentalresults demonstrate that the proposed dynamic thermal coupling model accurately captured thethermal behavior of OMP,outperforming the static thermal parameter model.Overall,thisadvancement is crucial for effectively monitoring the health of EHA and ensuring flight safety.展开更多
The numerical simulation of the fluid flow and the flexible rod(s)interaction is more complicated and has lower efficiency due to the high computational cost.In this paper,a semi-resolved model coupling the computatio...The numerical simulation of the fluid flow and the flexible rod(s)interaction is more complicated and has lower efficiency due to the high computational cost.In this paper,a semi-resolved model coupling the computational fluid dynamics and the flexible rod dynamics is proposed using a two-way domain expansion method.The gov-erning equations of the flexible rod dynamics are discretized and solved by the finite element method,and the fluid flow is simulated by the finite volume method.The interaction between fluids and solid rods is modeled by introducing body force terms into the momentum equations.Referred to the traditional semi-resolved numerical model,an anisotropic Gaussian kernel function method is proposed to specify the interactive forces between flu-ids and solid bodies for non-circle rod cross-sections.A benchmark of the flow passing around a single flexible plate with a rectangular cross-section is used to validate the algorithm.Focused on the engineering applications,a test case of a finite patch of cylinders is implemented to validate the accuracy and efficiency of the coupled model.展开更多
In the present work,the laminar plasma surface hardening method is employed to enhance the service life of metal components fabricated from 65 Mn steel.The mechanical and wear behaviors of the laminar plasma surface h...In the present work,the laminar plasma surface hardening method is employed to enhance the service life of metal components fabricated from 65 Mn steel.The mechanical and wear behaviors of the laminar plasma surface hardened 65 Mn steel were analyzed.The martensite transition transformation of the temperature of the laminar plasma-hardened 65 ferrite Mn steel was determined by a thermal-solid coupling model.Based on the orthogonal experimental results,the optimal hardening parameters were confirmed.The scanning velocity,quenching distance and arc current are 130 mm/min,50 mm and 120 A,respectively.The pearlites and ferrites are transformed into martensites in the hardened zone,while the ratio of martensite in the heataffected zone decreases with the increase in the hardening depth.Compared to the untreated 65Mn steel,the average hardness increases from 220 HV_(0.2)to 920 HV_(0.2)in the hardened zone and the corresponding absorbed power increases from 118.7 J to 175.5 J.At the same time,the average coefficient of friction(COF)decreases from 0.763 to 0.546,and the wear rate decreases from 5.39×10^(-6)mm^(3)/(N·m)to 2.95×10^(-6)mm^(3)/(N·m),indicating that the wear resistance of 65Mn steel could be significantly improved by using laminar surface hardening.With the same hardening parameters,the depth and width of the hardened zone predicted by the thermal-solid coupling model are 1.85 mm and 11.20 mm,respectively,which are in accordance with the experimental results;depth is 1.83 mm and width is 11.15 mm.In addition,the predicted hardness distributions of the simulation model are in accordance with the experimental results.These results indicate that the simulation model could effectively predict the microstructure characteristics of 65 Mn steel.展开更多
The aging characteristics of lithium-ion battery(LIB)under fast charging is investigated based on an electrochemical-thermal-mechanical(ETM)coupling model.Firstly,the ETM coupling model is established by COMSOL Multip...The aging characteristics of lithium-ion battery(LIB)under fast charging is investigated based on an electrochemical-thermal-mechanical(ETM)coupling model.Firstly,the ETM coupling model is established by COMSOL Multiphysics.Subsequently,a long cycle test was conducted to explore the aging characteristics of LIB.Specifically,the effects of charging(C)rate and cycle number on battery aging are analyzed in terms of nonuniform distribution of solid electrolyte interface(SEI),SEI formation,thermal stability and stress characteristics.The results indicate that the increases in C rate and cycling led to an increase in the degree of nonuniform distribution of SEI,and thus a consequent increase in the capacity loss due to the SEI formation.Meanwhile,the increases in C rate and cycle number also led to an increase in the heat generation and a decrease in the heat dissipation rate of the battery,respectively,which result in a decrease in the thermal stability of the electrode materials.In addition,the von Mises stress of the positive electrode material is higher than that of the negative electrode material as the cycling proceeds,with the positive electrode material exhibiting tensile deformation and the negative electrode material exhibiting compressive deformation.The available lithium ion concentration of the positive electrode is lower than that of the negative electrode,proving that the tensile-type fracture occurring in the positive material under long cycling dominated the capacity loss process.The aforementioned studies are helpful for researchers to further explore the aging behavior of LIB under fast charging and take corresponding preventive measures.展开更多
During high-speed flight,both thermal and mechani-cal loads can degrade the electrical performance of the antenna-radome system,which can subsequently affect the performance of the guidance system.This paper presents ...During high-speed flight,both thermal and mechani-cal loads can degrade the electrical performance of the antenna-radome system,which can subsequently affect the performance of the guidance system.This paper presents a method for evalu-ating the electrical performance of the radome when subjected to thermo-mechanical-electrical(TME)coupling.The method involves establishing a TME coupling model(TME-CM)based on the TME sharing mesh model(TME-SMM)generated by the tetrahedral mesh partitioning of the radome structure.The effects of dielectric temperature drift and structural deformation on the radome’s electrical performance are also considered.Firstly,the temperature field of the radome is obtained by tran-sient thermal analysis while the deformation field of the radome is obtained by static analysis.Subsequently,the dielectric varia-tion and structural deformation of the radome are accurately incorporated into the electrical simulation model based on the TME-SMM.The three-dimensional(3D)ray tracing method with the aperture integration technique is used to calculate the radome’s electrical performance.A representative example is provided to illustrate the superiority and necessity of the pro-posed method.This is achieved by calculating and analyzing the changes in the radome’s electrical performance over time dur-ing high-speed flight.展开更多
For the feature of complex weapon manufacturing on internet,a coupling model is proposed.By using the model,the correlation between manufacturing cells in an extended manufacturing organization can be evaluated quanti...For the feature of complex weapon manufacturing on internet,a coupling model is proposed.By using the model,the correlation between manufacturing cells in an extended manufacturing organization can be evaluated quantitatively,so an appropriate control plan is determined.A strategy to improve and reduce the coupling relationship of the organization is studied.A correlation matrix of extended tasks is built to analyze the relationship between sub-tasks and manufacturing resources.An optimization method for manufacturing resource configuration is presented based on the coupling model.Finally,a software system for analyzing coupling model about manufacturing organization on internet is developed,and the result shows that the coupling model is effective.展开更多
This paper, taking Hexi Corridor as an example, analyzes the altemating intimidation and the dynamic evolving relation between urbanization and eco-environment in arid area of West China. We argue that the harmonious ...This paper, taking Hexi Corridor as an example, analyzes the altemating intimidation and the dynamic evolving relation between urbanization and eco-environment in arid area of West China. We argue that the harmonious development system of the urbanization and eco-environment would go through four phases： rudimentary symbiotic phase, harmonious developmental phase, utmost increasing phase and spiral type rising phase. Throughout the four phases, the elements of the system would influence each other, coerce each other, and complete the spiral type rising process from low-grade symbiosis to high-grade harmony together. The study on Hexi Corridor shows that the urbanization level in Hexi Corridor has increased gradually from 1985 to 2003 accompanied with the fluctuations of eco-environment state. The response of eco-environment to urbanization has been evident, but lagged behind the urbanization course. At present, the harmonious development system in Hexi Corridor was in its harmonious developmental phase. However, the coupling degree has increased quickly and approached 90 yet, which is signaling that the system is about to enter the utmost increasing phase, and the ecological crisis will enter the latent period. We have found that the coupling degree can well reflect the interactive coercing and dynamic evolving situation between urbanization and eco-environment in Hexi Corridor. From the temporal change of the coupling degree, it can be concluded that urbanization sometimes needs to pay a certain cost for the damage of the eco-environment in its initial stages, but as the urbanization continues, the state of the eco-environment would be meliorated.展开更多
The interfacial heat transfer coefficient between hot profile surface and cooling water was determined by using inverse heat conduction model combined with end quenching experiment. Then, a Deform-3 D thermo-mechanica...The interfacial heat transfer coefficient between hot profile surface and cooling water was determined by using inverse heat conduction model combined with end quenching experiment. Then, a Deform-3 D thermo-mechanical coupling model for simulating the on-line water quenching of extruded profile with unequal and large thicknesses was developed. The temperature field, residual stress field and distortion of profile during quenching were investigated systematically. The results show that heat transfer coefficient increases as water flow rate increases. The peak heat transfer coefficient with higher water flow rates appears at lower interface temperatures. The temperature distribution across the cross-section of profile during quenching is severe nonuniform and the maximum temperature difference is 300 ℃ at quenching time of 3.49 s. The temperature difference through the thickness of different parts of profile first increases sharply to a maximum value, and then gradually decreases. The temperature gradient increases obviously with the increase of thickness of parts. After quenching, there exist large residual stresses on the inner side of joints of profile and the two ends of part with thickness of 10 mm. The profile presents a twisting-type distortion across the cross-section under non-uniform cooling and the maximum twisting angle during quenching is 2.78°.展开更多
Based on the surface energy balance model which is widely used abroad, a temperature and humidity field coupling model of conservatory soil without crop vegetation in full illumination was established. Considering the...Based on the surface energy balance model which is widely used abroad, a temperature and humidity field coupling model of conservatory soil without crop vegetation in full illumination was established. Considering the relatively closed environment in conservatory, weak solar radiation and little surface evaporation of soil, the daily variation of water content in different soil layers may be neglected, then the temperature and humidity field coupling model was simplified to a one-dimensional thermal diffusion model. The simplified model and the temperature and humidity field coupling model adopted the same computational method of soil physical parameters and discrete format of heat diffusion differential equations, and were applied to the continuous simulation of temperature field in conservatory soil without crop vegetation in full illumination. Through the comparison between simulation results and experimental data, the precision of the simplified model was verified. The typical rule of soil heat flux variation in a 24 h cycle was also obtained.展开更多
The seepage under a dam foundation is mainly controlled by the performance of the curtain.Its anti-seepage behavior may be weakened by the long term physic-chemical actions from groundwater.According to seepage hydrau...The seepage under a dam foundation is mainly controlled by the performance of the curtain.Its anti-seepage behavior may be weakened by the long term physic-chemical actions from groundwater.According to seepage hydraulics and geochemistry theory,a coupling model for assessing the behavior of the curtain under a dam foundation is set up,which consists of seepage module,solute transport module,geochemistry module and curtain erosion module,solved by FEM.A case study was carried out.The result shows that the curtain efficiency is weakened all the time.Aqueous calcium from the curtain is always in dissolution during the stress period for simulation,which leads to the increasing amount in groundwater reaching 846.35-865.312 g/m3.Within the domain,reaction extent differs in different parts of the curtain.The dissolution of Ca(OH)2 accounts to 877.884 g/m3 near the bottom and is much higher than that of the other parts.The erosion is much more serious near the bottom of the curtain than the other parts,which is the same to the upstream and downstream.Calcium dissolution is mainly controlled by hydraulic condition and dispersion,and it varies in a non-linear way within the domain.展开更多
In this paper, the importance of investigation on terrestrical processes in arid areas for mankind's living environment protection and local economy development as well as its present state of the art are elucidat...In this paper, the importance of investigation on terrestrical processes in arid areas for mankind's living environment protection and local economy development as well as its present state of the art are elucidated. A coupling model, which evaluates heat, mass, momentum and radiative fluxes in the SPAC system, is developed for simulating microclimate over plant and bare soil. Especially, it is focussed on the details of turbulence transfer. For illustration, numerical simulation of the water-heat exchange processes at Shapotou Observatory, GAS, Ninxia Province are conducted, and the computational results show that the laws of land-surface processes are rather typical in the arid areas.展开更多
We should calculate the coupling degree of medical investment, resident health and economic growth in Sichuan Province, and make clear the coordinated development of the aforementioned three factors. In that, the gove...We should calculate the coupling degree of medical investment, resident health and economic growth in Sichuan Province, and make clear the coordinated development of the aforementioned three factors. In that, the government was able to formulate policies that feature the positive interaction and coordinated development of regional medical investment, health and economy. Methods on index system for the evaluation of health investment, resident health and economic growth were constructed, and the coupling and coordination degree of the three systems were empirically studied based on the entropy weight method, the coupling coordination model and the gray correlation method. From the perspective of time series, the overall coupling and coordination level of Sichuan Province is relatively low, and the comprehensive development level of health investment and economic growth system has lagged behind the resident health system;from the perspective of spatial distribution characteristics, in 2019, the coordinated development level of health investment resident health and economic growth coupling in western Sichuan, southern Sichuan, northern Sichuan, eastern Sichuan and northern Sichuan is in the primary coordination stage, but there is a lag in the development of the health investment system between western Sichuan and southern Sichuan, and there is a lag in the development of the economic growth system between northern Sichuan and eastern Sichuan. From the analysis of gray correlation degree, the main correlation factors are diverse. All in all, the overall coordination level of health investment, resident health and economic growth in Sichuan Province is relatively low, and in order to achieve its coordinated development, it is necessary to narrow regional differences, formulate coordinated development strategies according to local conditions, and improve the overall coordination level.展开更多
A new Lagrangian—Eulerian coupling model system is developed to study regional air quality. The system consists of mesoscale dynamical meteorological model (MM), Monte—Carlo model (MCM), parameterized model on plane...A new Lagrangian—Eulerian coupling model system is developed to study regional air quality. The system consists of mesoscale dynamical meteorological model (MM), Monte—Carlo model (MCM), parameterized model on planetary boundary layer (PBL) turbulent statistics, dry and wet removal model, and Eulerian nonlinear chemical model (ENCM). The physical, chemical and biological processes on air pollutants are considered comprehensively. 3—D distribution laws tor acidic gaseous pollutants (SO2 and NOx) emitted by Thai Mae Moh Power Plant and the secondary pollutants are studied in detail. The results simulated by the coupling model system are in good agreement with observational concentration data. Key words MM - MCM - ENCM - Coupling model system The authors wish to express their thanks to Prof. Zeng Q. C. for his support to this research and to Dr. Han Z. W. and Zhang M. G. for their help in programming and numerical calculation of IAP, Chinese Academy of Sciences. Thanks are also due to NSTD and EGAT in Thailand for supporting this research.展开更多
A minimal system-plus-reservoir model yielding a nonergodic Langevin equation is proposed, which originates from the cubic-spectral density of environmental oscillators and momentum-dependent coupling. This model allo...A minimal system-plus-reservoir model yielding a nonergodic Langevin equation is proposed, which originates from the cubic-spectral density of environmental oscillators and momentum-dependent coupling. This model allows ballistic diffusion and classical localization simultaneously, in which the fluctuation-dissipation relation is still satisfied but the Khinchin theorem is broken. The asymptotical equilibrium for a nonergodic system requires the initial thermal equilibrium, however, when the system starts from nonthermal conditions, it does not approach the equilibration even though a nonlinear potential is used to bound the particle, this can be confirmed by the zerotb law of thermodynamics. In the dynamics of Brownian localization, due to the memory damping function inducing a constant term, our results show that the stationary distribution of the system depends on its initial preparation of coordinate rather than momentum. The coupled oscillator chain with a fixed end boundary acts as a heat bath, which has long been used in studies of collinear atom/solid-surface scattering and lattice vibration, we investigate this problem from the viewpoint of nonergodicity.展开更多
K^- condensation and quark deconfinement phase transitions in neutron stars are investigated. We use the modified quark-meson coupling model for hadronic phase and the MIT bag model for quark phase. With the equation ...K^- condensation and quark deconfinement phase transitions in neutron stars are investigated. We use the modified quark-meson coupling model for hadronic phase and the MIT bag model for quark phase. With the equation of state （EOS） solved self-consistently, we discuss the properties of neutron stars. We find that the EOS of pure hadron matter with condensed K- phase should be ruled out by the redshift for star EX00748-676, while EOS containing unpaired quark matter phase with B1/4 being about 180 MeV could be consistent with both this observation and the best measured mass of star PSR 1913 ＋ 16. But if the recent inferred massive star among Terzan 5 with M 〉 1.68M is confirmed, all the present EOSes with condensed phase and deconfined phase would be ruled out.展开更多
A Trous algorithm of wavelet transform was used to decompose wavelet signal, and the cross-correlation analysis was used to analyze the sequence of each wavelet transform, and then the mathematical model correspond wi...A Trous algorithm of wavelet transform was used to decompose wavelet signal, and the cross-correlation analysis was used to analyze the sequence of each wavelet transform, and then the mathematical model correspond with wavelet transform sequence was established, finally wavelet random coupling model was obtained by wavelet reconstruction algorithm. Then, according to the rainfall data in crop growth period of Farm Chahayang from 1956 to 2008, the wavelet random coupling model was established to fit the model prediction test. The results showed that the prediction and fitting accuracy of the model was high, the model could reflect the rainfall variation regulation in the region, and it was a practical prediction model. It was very important for us to determine reasonably irrigation schedule and to use efficiency coefficient of precipitation resource.展开更多
This study is concerned with developing a two-dimensional two-phase model that simulate the movement of non-aqueous phase liquid (NAPL) in a fracture-rock matrix system. The intrinsic permeability and the fracture ape...This study is concerned with developing a two-dimensional two-phase model that simulate the movement of non-aqueous phase liquid (NAPL) in a fracture-rock matrix system. The intrinsic permeability and the fracture aperture are represented in the model via its KarhunenLoeve expansion. Other parameters and the nodal unknowns, water saturations and water pressures, are represented by their stochastic spectral expansions. The errors resulting from truncation of Karhunen - Loeve and polynomial chaos expansions to a finite number of terms are analyzed. The eigenvalues of stochastic process is found out for any point in the special domain of the problem at any instant in time.展开更多
High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the...High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the embodiment of the national level of science and technology.展开更多
Clarifying the flow laws of shale gas under high temperature and high pressure is the prerequisite to accurately predicting the productivity of deep shale gas wells.In this paper,a self-diffusion flow model of flow fi...Clarifying the flow laws of shale gas under high temperature and high pressure is the prerequisite to accurately predicting the productivity of deep shale gas wells.In this paper,a self-diffusion flow model of flow field and temperature field coupling(referred to as self-diffusion flow and heat coupling model)was established based on the previously proposed self-diffusion flow model,while considering the influence of the temperature field change.Then,its calculation result was compared with that of the flow model based on Darcy's law and Knudsen diffusion(referred to as modified Darcy flow model).Based on the self-diffusion flow and heat coupling model,the self-diffusion flow behaviors of deep shale gas under the influence of temperature field change were analyzed,and the influence of bottomhole temperature on the degree of reserve recovery of deep shale gas was discussed.Finally,the self-diffusion flow and heat coupling model was applied to simulate the production of one shale-gas horizontal well in the Upper Ordovician Wufeng FormationeLower Silurian Longmaxi Formation in the Changning Block of the Sichuan Basin.And the following research results were obtained.First,at the same parameters,the shale gas production calculated by the selfdiffusion flow and heat coupling model is higher than the result calculated by the modified Darcy flow model.Second,when temperature field change is taken into consideration,the selfedviffusion coefficient profile presents a peak,the gas density profile presents a valley and the data points corresponding to the peak/valley move synchronously to the internal formation,which indicates that the selfediffusion coefficient influences the gas mass transfer rate,and the influence range of near well low temperature on gas self-diffusion increases continuously as the production continues.Third,when the bottomhole temperature is lower than the formation temperature,the selfediffusion coefficient of the gas near the well decreases and the gas is blocked near the well,which reduces the gas well production.Fourth,the production simulation result of the case well shows that the self-diffusion flow and heat coupling model can predict the production of deep shale gas more accurately if temperature field change is taken into consideration.In conclusion,the self-diffusion flow and heat coupling model established in this paper is of higher reliability and accuracy and can be used for productivity simulation and prediction of deep shale gas wells.The conclusion of this paper has certain guiding significance for deep shale gas production and gas well productivity prediction.展开更多
Geothermal energy is a kind of renewable,sustainable and clean energy resource.Geothermal energy is abundant in carbonate reservoirs.However,low matrix permeability limits its exploitation.The super-critical carbon di...Geothermal energy is a kind of renewable,sustainable and clean energy resource.Geothermal energy is abundant in carbonate reservoirs.However,low matrix permeability limits its exploitation.The super-critical carbon dioxide(SC-CO_(2))jet fracturing is expected to efficiently stimulate the carbonate geothermal reservoirs and achieve the storage of CO_(2) simultaneously.In this paper,we established a transient seepage and fluid-thermo-mechanical coupled model to analyze the impact performance of sc-CO_(2) jet fracturing.The mesh-based parallel code coupling interface was employed to couple the fluid and solid domains by exchanging the data through the mesh interface.The physical properties change of sC-CO_(2) with temperature were considered in the numerical model.Results showed that SC-CO_(2) jet frac-turing is superior to water-jet fracturing with respect to jetting velocity,particle trajectory and pene-trability.Besides,stress distribution on the carbonate rock showed that the tensile and shear failure would more easily occur by SC-CO_(2) jet than that by water jet.Moreover,pressure and temperature control the jet field and seepage field of sC-CO_(2) simultaneously.Increasing the jet temperature can effectively enhance the impingement effect and seepage process by decreasing the viscosity and density of SC-CO_(2).The key findings are expected to provide a theoretical basis and design reference for applying SC-CO_(2) jet fracturing in carbonate geothermal reservoirs.展开更多
基金supported by the National Key R&D Program of China(No.2021YFB2011300)the National Natural Science Foundation of China(Nos.52275044,U2233212)。
文摘The Electro–Hydrostatic Actuator(EHA)is applied to drive the control surface in flightcontrol system of more electric aircraft.In EHA,the Oil-Immersed Motor Pump(OMP)serves asthe core as a power assembly.However,the compact integration of the OMP presents challenges inefficiently dissipating internal heat,leading to a performance degradation of the EHA due to ele-vated temperatures.Therefore,accurately modeling and predicting the internal thermal dynamicsof the OMP hold considerable significance for monitoring the operational condition of the EHA.In view of this,a modeling method considering cumulative thermal coupling was hereby proposed.Based on the proposed method,the thermal models of the motor and the pump were established,taking into account heat accumulation and transfer.Taking the leakage oil as the heat couplingpoint between the motor and the pump,the dynamic thermal coupling model of the OMP wasdeveloped,with the thermal characteristics of the oil considered.Additionally,the comparativeexperiments were conducted to illustrate the efficiency of the proposed model.The experimentalresults demonstrate that the proposed dynamic thermal coupling model accurately captured thethermal behavior of OMP,outperforming the static thermal parameter model.Overall,thisadvancement is crucial for effectively monitoring the health of EHA and ensuring flight safety.
基金supported by Shanghai 2021“Science and Technology Innovation Action Plan”:Social Development Science and Technology Research Project(Grant No.21DZ1202703).
文摘The numerical simulation of the fluid flow and the flexible rod(s)interaction is more complicated and has lower efficiency due to the high computational cost.In this paper,a semi-resolved model coupling the computational fluid dynamics and the flexible rod dynamics is proposed using a two-way domain expansion method.The gov-erning equations of the flexible rod dynamics are discretized and solved by the finite element method,and the fluid flow is simulated by the finite volume method.The interaction between fluids and solid rods is modeled by introducing body force terms into the momentum equations.Referred to the traditional semi-resolved numerical model,an anisotropic Gaussian kernel function method is proposed to specify the interactive forces between flu-ids and solid bodies for non-circle rod cross-sections.A benchmark of the flow passing around a single flexible plate with a rectangular cross-section is used to validate the algorithm.Focused on the engineering applications,a test case of a finite patch of cylinders is implemented to validate the accuracy and efficiency of the coupled model.
基金appreciate the support of the Key Laboratory of Mechanical Structure Optimization&Material Application Technology of Luzhou(No.SCHYZSA-2022-02)the Scientific Research and Innovation Team Program of Sichuan University of Science and Technology(No.SUSE652A004)+1 种基金the Key Laboratory of Intelligent Manufacturing of Construction Machinery Project(No.IMCM202103)the Panzhihua Key Laboratory of Advanced Manufacturing Technology Open Fund Project(No.2022XJZD01)。
文摘In the present work,the laminar plasma surface hardening method is employed to enhance the service life of metal components fabricated from 65 Mn steel.The mechanical and wear behaviors of the laminar plasma surface hardened 65 Mn steel were analyzed.The martensite transition transformation of the temperature of the laminar plasma-hardened 65 ferrite Mn steel was determined by a thermal-solid coupling model.Based on the orthogonal experimental results,the optimal hardening parameters were confirmed.The scanning velocity,quenching distance and arc current are 130 mm/min,50 mm and 120 A,respectively.The pearlites and ferrites are transformed into martensites in the hardened zone,while the ratio of martensite in the heataffected zone decreases with the increase in the hardening depth.Compared to the untreated 65Mn steel,the average hardness increases from 220 HV_(0.2)to 920 HV_(0.2)in the hardened zone and the corresponding absorbed power increases from 118.7 J to 175.5 J.At the same time,the average coefficient of friction(COF)decreases from 0.763 to 0.546,and the wear rate decreases from 5.39×10^(-6)mm^(3)/(N·m)to 2.95×10^(-6)mm^(3)/(N·m),indicating that the wear resistance of 65Mn steel could be significantly improved by using laminar surface hardening.With the same hardening parameters,the depth and width of the hardened zone predicted by the thermal-solid coupling model are 1.85 mm and 11.20 mm,respectively,which are in accordance with the experimental results;depth is 1.83 mm and width is 11.15 mm.In addition,the predicted hardness distributions of the simulation model are in accordance with the experimental results.These results indicate that the simulation model could effectively predict the microstructure characteristics of 65 Mn steel.
基金funded by the National Natural Science Foundation of China(Grant No.12272217)。
文摘The aging characteristics of lithium-ion battery(LIB)under fast charging is investigated based on an electrochemical-thermal-mechanical(ETM)coupling model.Firstly,the ETM coupling model is established by COMSOL Multiphysics.Subsequently,a long cycle test was conducted to explore the aging characteristics of LIB.Specifically,the effects of charging(C)rate and cycle number on battery aging are analyzed in terms of nonuniform distribution of solid electrolyte interface(SEI),SEI formation,thermal stability and stress characteristics.The results indicate that the increases in C rate and cycling led to an increase in the degree of nonuniform distribution of SEI,and thus a consequent increase in the capacity loss due to the SEI formation.Meanwhile,the increases in C rate and cycle number also led to an increase in the heat generation and a decrease in the heat dissipation rate of the battery,respectively,which result in a decrease in the thermal stability of the electrode materials.In addition,the von Mises stress of the positive electrode material is higher than that of the negative electrode material as the cycling proceeds,with the positive electrode material exhibiting tensile deformation and the negative electrode material exhibiting compressive deformation.The available lithium ion concentration of the positive electrode is lower than that of the negative electrode,proving that the tensile-type fracture occurring in the positive material under long cycling dominated the capacity loss process.The aforementioned studies are helpful for researchers to further explore the aging behavior of LIB under fast charging and take corresponding preventive measures.
文摘During high-speed flight,both thermal and mechani-cal loads can degrade the electrical performance of the antenna-radome system,which can subsequently affect the performance of the guidance system.This paper presents a method for evalu-ating the electrical performance of the radome when subjected to thermo-mechanical-electrical(TME)coupling.The method involves establishing a TME coupling model(TME-CM)based on the TME sharing mesh model(TME-SMM)generated by the tetrahedral mesh partitioning of the radome structure.The effects of dielectric temperature drift and structural deformation on the radome’s electrical performance are also considered.Firstly,the temperature field of the radome is obtained by tran-sient thermal analysis while the deformation field of the radome is obtained by static analysis.Subsequently,the dielectric varia-tion and structural deformation of the radome are accurately incorporated into the electrical simulation model based on the TME-SMM.The three-dimensional(3D)ray tracing method with the aperture integration technique is used to calculate the radome’s electrical performance.A representative example is provided to illustrate the superiority and necessity of the pro-posed method.This is achieved by calculating and analyzing the changes in the radome’s electrical performance over time dur-ing high-speed flight.
基金Supported by the National Defense Industrial Technology Development Program of China~~
文摘For the feature of complex weapon manufacturing on internet,a coupling model is proposed.By using the model,the correlation between manufacturing cells in an extended manufacturing organization can be evaluated quantitatively,so an appropriate control plan is determined.A strategy to improve and reduce the coupling relationship of the organization is studied.A correlation matrix of extended tasks is built to analyze the relationship between sub-tasks and manufacturing resources.An optimization method for manufacturing resource configuration is presented based on the coupling model.Finally,a software system for analyzing coupling model about manufacturing organization on internet is developed,and the result shows that the coupling model is effective.
基金NationalNaturalScience Emphases Foundation ofChina,No.40335049NationalNaturalScience Foundation ofChina,No.40471059
文摘This paper, taking Hexi Corridor as an example, analyzes the altemating intimidation and the dynamic evolving relation between urbanization and eco-environment in arid area of West China. We argue that the harmonious development system of the urbanization and eco-environment would go through four phases： rudimentary symbiotic phase, harmonious developmental phase, utmost increasing phase and spiral type rising phase. Throughout the four phases, the elements of the system would influence each other, coerce each other, and complete the spiral type rising process from low-grade symbiosis to high-grade harmony together. The study on Hexi Corridor shows that the urbanization level in Hexi Corridor has increased gradually from 1985 to 2003 accompanied with the fluctuations of eco-environment state. The response of eco-environment to urbanization has been evident, but lagged behind the urbanization course. At present, the harmonious development system in Hexi Corridor was in its harmonious developmental phase. However, the coupling degree has increased quickly and approached 90 yet, which is signaling that the system is about to enter the utmost increasing phase, and the ecological crisis will enter the latent period. We have found that the coupling degree can well reflect the interactive coercing and dynamic evolving situation between urbanization and eco-environment in Hexi Corridor. From the temporal change of the coupling degree, it can be concluded that urbanization sometimes needs to pay a certain cost for the damage of the eco-environment in its initial stages, but as the urbanization continues, the state of the eco-environment would be meliorated.
基金Project(51605234)supported by the National Natural Science Foundation of ChinaProjects(2019JJ50510,2019JJ70077)supported by the Natural Science Foundation of Hunan Province,ChinaProjects(18B285,18B552)supported by Scientific Research Fund of Hunan Provincial Education Department,China。
文摘The interfacial heat transfer coefficient between hot profile surface and cooling water was determined by using inverse heat conduction model combined with end quenching experiment. Then, a Deform-3 D thermo-mechanical coupling model for simulating the on-line water quenching of extruded profile with unequal and large thicknesses was developed. The temperature field, residual stress field and distortion of profile during quenching were investigated systematically. The results show that heat transfer coefficient increases as water flow rate increases. The peak heat transfer coefficient with higher water flow rates appears at lower interface temperatures. The temperature distribution across the cross-section of profile during quenching is severe nonuniform and the maximum temperature difference is 300 ℃ at quenching time of 3.49 s. The temperature difference through the thickness of different parts of profile first increases sharply to a maximum value, and then gradually decreases. The temperature gradient increases obviously with the increase of thickness of parts. After quenching, there exist large residual stresses on the inner side of joints of profile and the two ends of part with thickness of 10 mm. The profile presents a twisting-type distortion across the cross-section under non-uniform cooling and the maximum twisting angle during quenching is 2.78°.
文摘Based on the surface energy balance model which is widely used abroad, a temperature and humidity field coupling model of conservatory soil without crop vegetation in full illumination was established. Considering the relatively closed environment in conservatory, weak solar radiation and little surface evaporation of soil, the daily variation of water content in different soil layers may be neglected, then the temperature and humidity field coupling model was simplified to a one-dimensional thermal diffusion model. The simplified model and the temperature and humidity field coupling model adopted the same computational method of soil physical parameters and discrete format of heat diffusion differential equations, and were applied to the continuous simulation of temperature field in conservatory soil without crop vegetation in full illumination. Through the comparison between simulation results and experimental data, the precision of the simplified model was verified. The typical rule of soil heat flux variation in a 24 h cycle was also obtained.
基金Project(50139030) supported by the National Natural Science Foundation of ChinaProject(501072) supported by the Scientific Research Foundation for the Returned Overseas Scholars of the Ministry of Education of China
文摘The seepage under a dam foundation is mainly controlled by the performance of the curtain.Its anti-seepage behavior may be weakened by the long term physic-chemical actions from groundwater.According to seepage hydraulics and geochemistry theory,a coupling model for assessing the behavior of the curtain under a dam foundation is set up,which consists of seepage module,solute transport module,geochemistry module and curtain erosion module,solved by FEM.A case study was carried out.The result shows that the curtain efficiency is weakened all the time.Aqueous calcium from the curtain is always in dissolution during the stress period for simulation,which leads to the increasing amount in groundwater reaching 846.35-865.312 g/m3.Within the domain,reaction extent differs in different parts of the curtain.The dissolution of Ca(OH)2 accounts to 877.884 g/m3 near the bottom and is much higher than that of the other parts.The erosion is much more serious near the bottom of the curtain than the other parts,which is the same to the upstream and downstream.Calcium dissolution is mainly controlled by hydraulic condition and dispersion,and it varies in a non-linear way within the domain.
文摘In this paper, the importance of investigation on terrestrical processes in arid areas for mankind's living environment protection and local economy development as well as its present state of the art are elucidated. A coupling model, which evaluates heat, mass, momentum and radiative fluxes in the SPAC system, is developed for simulating microclimate over plant and bare soil. Especially, it is focussed on the details of turbulence transfer. For illustration, numerical simulation of the water-heat exchange processes at Shapotou Observatory, GAS, Ninxia Province are conducted, and the computational results show that the laws of land-surface processes are rather typical in the arid areas.
文摘We should calculate the coupling degree of medical investment, resident health and economic growth in Sichuan Province, and make clear the coordinated development of the aforementioned three factors. In that, the government was able to formulate policies that feature the positive interaction and coordinated development of regional medical investment, health and economy. Methods on index system for the evaluation of health investment, resident health and economic growth were constructed, and the coupling and coordination degree of the three systems were empirically studied based on the entropy weight method, the coupling coordination model and the gray correlation method. From the perspective of time series, the overall coupling and coordination level of Sichuan Province is relatively low, and the comprehensive development level of health investment and economic growth system has lagged behind the resident health system;from the perspective of spatial distribution characteristics, in 2019, the coordinated development level of health investment resident health and economic growth coupling in western Sichuan, southern Sichuan, northern Sichuan, eastern Sichuan and northern Sichuan is in the primary coordination stage, but there is a lag in the development of the health investment system between western Sichuan and southern Sichuan, and there is a lag in the development of the economic growth system between northern Sichuan and eastern Sichuan. From the analysis of gray correlation degree, the main correlation factors are diverse. All in all, the overall coordination level of health investment, resident health and economic growth in Sichuan Province is relatively low, and in order to achieve its coordinated development, it is necessary to narrow regional differences, formulate coordinated development strategies according to local conditions, and improve the overall coordination level.
文摘A new Lagrangian—Eulerian coupling model system is developed to study regional air quality. The system consists of mesoscale dynamical meteorological model (MM), Monte—Carlo model (MCM), parameterized model on planetary boundary layer (PBL) turbulent statistics, dry and wet removal model, and Eulerian nonlinear chemical model (ENCM). The physical, chemical and biological processes on air pollutants are considered comprehensively. 3—D distribution laws tor acidic gaseous pollutants (SO2 and NOx) emitted by Thai Mae Moh Power Plant and the secondary pollutants are studied in detail. The results simulated by the coupling model system are in good agreement with observational concentration data. Key words MM - MCM - ENCM - Coupling model system The authors wish to express their thanks to Prof. Zeng Q. C. for his support to this research and to Dr. Han Z. W. and Zhang M. G. for their help in programming and numerical calculation of IAP, Chinese Academy of Sciences. Thanks are also due to NSTD and EGAT in Thailand for supporting this research.
基金supported by the National Natural Science Foundation of China (Grant No. 11175021)
文摘A minimal system-plus-reservoir model yielding a nonergodic Langevin equation is proposed, which originates from the cubic-spectral density of environmental oscillators and momentum-dependent coupling. This model allows ballistic diffusion and classical localization simultaneously, in which the fluctuation-dissipation relation is still satisfied but the Khinchin theorem is broken. The asymptotical equilibrium for a nonergodic system requires the initial thermal equilibrium, however, when the system starts from nonthermal conditions, it does not approach the equilibration even though a nonlinear potential is used to bound the particle, this can be confirmed by the zerotb law of thermodynamics. In the dynamics of Brownian localization, due to the memory damping function inducing a constant term, our results show that the stationary distribution of the system depends on its initial preparation of coordinate rather than momentum. The coupled oscillator chain with a fixed end boundary acts as a heat bath, which has long been used in studies of collinear atom/solid-surface scattering and lattice vibration, we investigate this problem from the viewpoint of nonergodicity.
基金National Natural Science Foundation of China under Grant Nos.10305001,10475002,and 10435080
文摘K^- condensation and quark deconfinement phase transitions in neutron stars are investigated. We use the modified quark-meson coupling model for hadronic phase and the MIT bag model for quark phase. With the equation of state （EOS） solved self-consistently, we discuss the properties of neutron stars. We find that the EOS of pure hadron matter with condensed K- phase should be ruled out by the redshift for star EX00748-676, while EOS containing unpaired quark matter phase with B1/4 being about 180 MeV could be consistent with both this observation and the best measured mass of star PSR 1913 ＋ 16. But if the recent inferred massive star among Terzan 5 with M 〉 1.68M is confirmed, all the present EOSes with condensed phase and deconfined phase would be ruled out.
基金Supported by Doctoral Foundation Program of Northeast Agricultural University (E090202)Science and Technology Research Program of Educational Committee of Heilongjiang Province, China (11551044)
文摘A Trous algorithm of wavelet transform was used to decompose wavelet signal, and the cross-correlation analysis was used to analyze the sequence of each wavelet transform, and then the mathematical model correspond with wavelet transform sequence was established, finally wavelet random coupling model was obtained by wavelet reconstruction algorithm. Then, according to the rainfall data in crop growth period of Farm Chahayang from 1956 to 2008, the wavelet random coupling model was established to fit the model prediction test. The results showed that the prediction and fitting accuracy of the model was high, the model could reflect the rainfall variation regulation in the region, and it was a practical prediction model. It was very important for us to determine reasonably irrigation schedule and to use efficiency coefficient of precipitation resource.
文摘This study is concerned with developing a two-dimensional two-phase model that simulate the movement of non-aqueous phase liquid (NAPL) in a fracture-rock matrix system. The intrinsic permeability and the fracture aperture are represented in the model via its KarhunenLoeve expansion. Other parameters and the nodal unknowns, water saturations and water pressures, are represented by their stochastic spectral expansions. The errors resulting from truncation of Karhunen - Loeve and polynomial chaos expansions to a finite number of terms are analyzed. The eigenvalues of stochastic process is found out for any point in the special domain of the problem at any instant in time.
文摘High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the embodiment of the national level of science and technology.
基金Project supported by the Youth Science Foundation Project of National Natural Science Foundation of China“Dynamic Evolution Mechanism of Shale Reservoir Stress Field under Multi-well Interference”(No.5190040058)the General Project of National Natural Science Foundation of China“Research on Hydrodynamic Mechanism of Multi-scale Channels in Tight Reservoir”,(No.51874321)the Scientific Research Foundation of China University of Petroleum(Beijing)for Young Top Talent“Multi-scale Characteristics of Fluid Flow in Complex Fracture Network of Shale Gas Reservoirs”(No.2462018YJRC014).
文摘Clarifying the flow laws of shale gas under high temperature and high pressure is the prerequisite to accurately predicting the productivity of deep shale gas wells.In this paper,a self-diffusion flow model of flow field and temperature field coupling(referred to as self-diffusion flow and heat coupling model)was established based on the previously proposed self-diffusion flow model,while considering the influence of the temperature field change.Then,its calculation result was compared with that of the flow model based on Darcy's law and Knudsen diffusion(referred to as modified Darcy flow model).Based on the self-diffusion flow and heat coupling model,the self-diffusion flow behaviors of deep shale gas under the influence of temperature field change were analyzed,and the influence of bottomhole temperature on the degree of reserve recovery of deep shale gas was discussed.Finally,the self-diffusion flow and heat coupling model was applied to simulate the production of one shale-gas horizontal well in the Upper Ordovician Wufeng FormationeLower Silurian Longmaxi Formation in the Changning Block of the Sichuan Basin.And the following research results were obtained.First,at the same parameters,the shale gas production calculated by the selfdiffusion flow and heat coupling model is higher than the result calculated by the modified Darcy flow model.Second,when temperature field change is taken into consideration,the selfedviffusion coefficient profile presents a peak,the gas density profile presents a valley and the data points corresponding to the peak/valley move synchronously to the internal formation,which indicates that the selfediffusion coefficient influences the gas mass transfer rate,and the influence range of near well low temperature on gas self-diffusion increases continuously as the production continues.Third,when the bottomhole temperature is lower than the formation temperature,the selfediffusion coefficient of the gas near the well decreases and the gas is blocked near the well,which reduces the gas well production.Fourth,the production simulation result of the case well shows that the self-diffusion flow and heat coupling model can predict the production of deep shale gas more accurately if temperature field change is taken into consideration.In conclusion,the self-diffusion flow and heat coupling model established in this paper is of higher reliability and accuracy and can be used for productivity simulation and prediction of deep shale gas wells.The conclusion of this paper has certain guiding significance for deep shale gas production and gas well productivity prediction.
基金the National Key R&D Program of China(No.2019YFB1504102).
文摘Geothermal energy is a kind of renewable,sustainable and clean energy resource.Geothermal energy is abundant in carbonate reservoirs.However,low matrix permeability limits its exploitation.The super-critical carbon dioxide(SC-CO_(2))jet fracturing is expected to efficiently stimulate the carbonate geothermal reservoirs and achieve the storage of CO_(2) simultaneously.In this paper,we established a transient seepage and fluid-thermo-mechanical coupled model to analyze the impact performance of sc-CO_(2) jet fracturing.The mesh-based parallel code coupling interface was employed to couple the fluid and solid domains by exchanging the data through the mesh interface.The physical properties change of sC-CO_(2) with temperature were considered in the numerical model.Results showed that SC-CO_(2) jet frac-turing is superior to water-jet fracturing with respect to jetting velocity,particle trajectory and pene-trability.Besides,stress distribution on the carbonate rock showed that the tensile and shear failure would more easily occur by SC-CO_(2) jet than that by water jet.Moreover,pressure and temperature control the jet field and seepage field of sC-CO_(2) simultaneously.Increasing the jet temperature can effectively enhance the impingement effect and seepage process by decreasing the viscosity and density of SC-CO_(2).The key findings are expected to provide a theoretical basis and design reference for applying SC-CO_(2) jet fracturing in carbonate geothermal reservoirs.
