The sound field driven by piping systems in enclosures may severely affect living comfort,which is frequently encountered in various engineering applications.Managing this sound field relies heavily on the available p...The sound field driven by piping systems in enclosures may severely affect living comfort,which is frequently encountered in various engineering applications.Managing this sound field relies heavily on the available prediction tools at hand,e.g.,the widely used finite element methods are computationally expensive due to the necessity to discretize entire space,analytical models,based on modal expansion method,may offer substantial advantages in terms of computational cost and efficiency.However,deriving eigenmodes of irregular enclosed spaces may be challenging,which impedes accurate and rapid predictions of the sound field in practical applications.This study presents an analytical framework aimed at rapidly and accurately predicting the interior sound field driven by the piping system vibrations in irregular enclosures.Vibration response of the piping system is obtained using the wave approach,and a line dipole source is idealized as the sound source of the piping system vibration.On the basis of eigenmodes of regular enclosures,the Kirchhoff-Helmholtz integral theorem(modal ex-pansion method for irregular enclosures)is introduced to account for the boundaries of irregular enclosures.This theoretical framework is validated through numerical simulations by finite element method and experiments,demonstrating high accuracy and significant efficiency advantages.The proposed method can be further employed to optimize radiated sound fields by tailoring the impedance of space walls or layout of piping systems.This study provides an efficient tool for predicting radiated sound field in general enclosures driven by vibration of piping systems,paving a new path for indoor acoustical optimization.展开更多
This paper aims to evaluate the feasibility of pressure-dependent models in the design of ship piping systems.For this purpose,a complex ship piping system is designed to operate in firefighting and bilge services thr...This paper aims to evaluate the feasibility of pressure-dependent models in the design of ship piping systems.For this purpose,a complex ship piping system is designed to operate in firefighting and bilge services through jet pumps.The system is solved as pressure-dependent model by the piping system analysis software EPANET and by a mathematical approach involving a piping network model.This results in a functional system that guarantees the recommendable ranges of hydraulic state variables(flow and pressure)and compliance with the rules of ship classification societies.Through this research,the suitability and viability of pressure-dependent models in the simulation of a ship piping system are proven.展开更多
Flow distribution in branch piping system is affected by flow characteristics and different geometric variations. Most of the flow distribution studies are performed with one-dimensional analysis to yield overall info...Flow distribution in branch piping system is affected by flow characteristics and different geometric variations. Most of the flow distribution studies are performed with one-dimensional analysis to yield overall information only. However, detailed analysis is required to find effects of design parameters on the flow distribution. For this aspect, three-dimensional turbulent flow analysis was performed to assess turbulence model performance and effects of upstream pressure and branch pipe geometry. Three different turbulence models of standard k-e model, realizable k-e model and standard k-co yield similar results, indicating small effects of turbulence models on flow characteristics analysis. Geometric variations include area ratio of main and branch pipes, branch pipe diameter, and connection shape of main and branch pipes. Among these parameters, area ratio and branch diameter and shape show strong effect on flow distribution due to high friction and minor loss. Uniform flow distribution is one of common requirements in the branch piping system and this can be achieved with rather high total loss design.展开更多
Augmented Reality(AR)applications can be used to improve tasks and mitigate errors during facilities operation and maintenance.This article presents an AR system for facility management using a three-dimensional(3D)ob...Augmented Reality(AR)applications can be used to improve tasks and mitigate errors during facilities operation and maintenance.This article presents an AR system for facility management using a three-dimensional(3D)object tracking method.Through spatial mapping,the object of interest,a pipe trap underneath a sink,is tracked and mixed onto the AR visualization.From that,the maintenance steps are transformed into visible and animated instructions.Although some tracking issues related to the component parts were observed,the designed AR application results demonstrated the potential to improve facility management tasks.展开更多
The present paper studies the dynamic pehaviour of a complex piping system containing internal fluid flow.A generalized complex modal decomposition method is proposed for modeling the piping structure.A characteristic...The present paper studies the dynamic pehaviour of a complex piping system containing internal fluid flow.A generalized complex modal decomposition method is proposed for modeling the piping structure.A characteristic impedance transfer matrix of piping flow with a frequency-dependent friction is employed for describing the model of fluid flow,which is coupled to the structural model by means of an approach similar to that used in the structural modal synthesis.The coupled model is practicable for the detecting,monitoring,controlling or predicting of piping vibrations,and for the studying of fluid dynamic characteristics under the influence of structural vibration,also for the diagnosticating of the piping system.展开更多
The modal analysis of piping system in air conditioner (AC) outdoor unit is essential to investigate the vibration properties of the system. In view of the growing significance of numerical finite element (FE) model f...The modal analysis of piping system in air conditioner (AC) outdoor unit is essential to investigate the vibration properties of the system. In view of the growing significance of numerical finite element (FE) model for vibration behaviour prediction, the AC piping elastic end support characterization has been explored. The axial and radial stiffness variables (ka, kr1, kr2) of the compressor-piping mounting are obtained and represented by dynamic stiffness of compressor grommet. They are obtained from dynamic load deflection test based on compressor operating condition such as excitation frequency and amplitude. The unknown stiffness variables of the other tube end (chassis-piping mounting) are determined by parameter fine tuning. An experimental modal analysis using impact hammer test has also been employed to determine the vibration properties such as natural frequencies, mode shapes and damping ratio of the piping structures. The modal parameters acquisition using SCADAS mobile acquisition system and LMS Impact Testing software is compared with the corresponding simulated modal properties using Abaqus. Most of the simulated natural frequencies achieve good correlation with the measured frequencies and it is reasonably a good prediction model to predict vibration behaviour of AC piping structures.展开更多
Manufacturing of ship piping systems is one of the major production activities in shipbuilding. The schedule of pipe production has an important impact on the master schedule of shipbuilding. In this research, the ITO...Manufacturing of ship piping systems is one of the major production activities in shipbuilding. The schedule of pipe production has an important impact on the master schedule of shipbuilding. In this research, the ITOC concept was introduced to solve the scheduling problems of a piping factory, and an intelligent scheduling system was developed. The system, in which a product model, an operation model, a factory model, and a knowledge database of piping production were integrated, automated the planning process and production scheduling. Details of the above points were discussed. Moreover, an application of the system in a piping factory, which achieved a higher level of performance as measured by tardiness, lead time, and inventory, was demonstrated.展开更多
Manufacturing of ship piping system is one of the major production activities in shipbuilding.The schedule of pipe production has an important impact on master schedule of shipbuilding.In this research,the theory of c...Manufacturing of ship piping system is one of the major production activities in shipbuilding.The schedule of pipe production has an important impact on master schedule of shipbuilding.In this research,the theory of constraints(TOC) concept is introduced to solve the scheduling problems of piping factory,and an intelligent scheduling system is developed.The system integrates a product model,an operation model,a factory model and a knowledge database of piping production and can make the process planning and production scheduling automatically.In the paper,details of above points are discussed.Moreover,an application of the system in a piping factory,which achieves a higher level of performance as measured by tardiness,lead time and inventory,is demonstrated at the end of the paper.展开更多
To improve the thermal performance and temperature uniformity of battery pack,this paper presents a novel battery thermal management system(BTMS)that integrates oscillating heat pipe(OHP)technology with liquid cooling...To improve the thermal performance and temperature uniformity of battery pack,this paper presents a novel battery thermal management system(BTMS)that integrates oscillating heat pipe(OHP)technology with liquid cooling.The primary innovation of the new hybrid BTMS lies in the use of an OHP with vertically arranged evaporator and condenser,enabling dual heat transfer pathways through liquid cooling plate and OHP.This study experimentally investigates the performance characteristics of the⊥-shaped OHP and hybrid BTMS.Results show that lower filling ratios significantly enhance the OHP’s startup performance but reduce operational stability,with optimal performance achieved at a 26.1%filling ratio.Acetone,as a single working fluid,exhibited superior heat transfer performance under low-load conditions compared to mixed fluids,while the acetone/ethanol mixture,forming a non-azeotropic solution,minimized temperature fluctuations.At 100 W,the⊥-shaped OHP with a horizontally arranged evaporator demonstrated better heat transfer performance than 2D-OHP designs.Compared to a liquid BTMS using water coolant at 280 W,the hybrid BTMS reduced the equivalent thermal resistance(RBTMS)and maximum temperature difference(ΔTmax)by 8.06%and 19.1%,respectively.When graphene nanofluid was used as the coolant in hybrid BTMS,the battery pack’s average temperature(Tb)dropped from 52.2℃ to 47.9℃,with RBTMS andΔTmax decreasing by 20.1%and 32.7%,respectively.These findings underscore the hybrid BTMS’s suitability for high heat load applications,offering a promising solution for electric vehicle thermal management.展开更多
Industry and energy continue to require piston engines(PICE)at a high level worldwide.Therefore,science and technology must urgently work on improving the PICE working cycle.Improving the quality of the intake process...Industry and energy continue to require piston engines(PICE)at a high level worldwide.Therefore,science and technology must urgently work on improving the PICE working cycle.Improving the quality of the intake process of theworking fluid into the cylinder is one of the most effective ways to improve the operational performance of PICE.The purpose of the study was to assess the impact of various cylinder head(CylH)designs on the gas-dynamic and heat-exchange qualities of air flows within an engine model’s intake system.Three different CylH designs were studied:the basic configuration and upgraded cylinder heads with a square valve and a square valve port.These designs are innovative.Laboratory conditions were used to conduct the studies for stationary air flow.The experiments covered the range of Reynolds numbers from 8500 to 96,000.The intake system’s gas dynamics and heat transfer were determined using the thermal anemometry method,which was based on constant-temperature hot-wire anemometers.It has been established that the use of upgraded CylHs causes an increase in the turbulence number of flow by an average of 13.5%.Additionally,itwas found that the increase in the turbulence number of flowin the cylinder is about 19%when installing new CylH designs.It was shown that therewas an increase in the heat transfer coefficient in the intake pipe by 10%–40%when installing modernized CylH designs in the intake system.The article focused on the problems of increasing the turbulence level and intensifying the heat transfer of stationary air flow in the intake system,specifically in PICEs.The study’s findings are novel in the areas of applied gas dynamics and PICEs.展开更多
This study investigates the feasibility of a novel dual two-phase cooling system for thermal management in lithium-ion batteries used in electric vehicles(EVs).The proposed system aims to combine low-boiling dielectri...This study investigates the feasibility of a novel dual two-phase cooling system for thermal management in lithium-ion batteries used in electric vehicles(EVs).The proposed system aims to combine low-boiling dielectric fluid immersion cooling and pulsating heat pipes(PHPs),in order to leverage the advantages of both technologies for efficient heat dissipation in a completely passive configuration.Experimental evaluations conducted under different discharge conditions demonstrate that the systemeffectivelymaintains battery temperatureswithin the optimal range of 20–40℃,with enhanced temperature uniformity and stability.While the PHP exhibited minimal impact at low power,its role became critical under higher discharge rates,ensuring efficient vapor condensation and pressure stability.The results highlight the potential of this passive cooling system to improve battery performance and safety,supporting its application in EV battery thermal management.Future work aims to optimize design parameters and evaluate real battery modules under ultra-fast charging scenarios.展开更多
The double-beam system is a crucial foundational structure in industry,with extensive application contexts and significant research value.The double-beam system with damping and gyroscopic effects is termed as the dam...The double-beam system is a crucial foundational structure in industry,with extensive application contexts and significant research value.The double-beam system with damping and gyroscopic effects is termed as the damped gyroscopic double-beam system.In such systems,the orthogonality conditions of the undamped double-beam system are no longer applicable,rendering it impossible to decouple them in modal space using the modal superposition method(MSM) to obtain analytical solutions.Based on the complex modal method and state space method,this paper takes the damped pipe-in-pipe(PIP) system as an example to solve this problem.The concepts of the original system and adjoint system are introduced,and the orthogonality conditions of the damped PIP system are given in the state-space.Based on the derived orthogonality conditions,the transient and steady-state response solutions are obtained.In the numerical discussion section,the convergence and accuracy of the solutions are verified.In addition,the dynamic responses of the system under different excitations and initial conditions are studied,and the forward and reverse synchronous vibrations in the PIP system are discussed.Overall,the method presented in this paper provides a convenient way to analyze the dynamics of the damped gyroscopic double-beam system.展开更多
Targeting spontaneous coal combustion during stacking,we developed an efficient heat dissipation&self-supplied wireless temperature measurement system(SPWTM)with gravity heat pipe-thermoelectric integration for du...Targeting spontaneous coal combustion during stacking,we developed an efficient heat dissipation&self-supplied wireless temperature measurement system(SPWTM)with gravity heat pipe-thermoelectric integration for dual safety.The heat transfer characteristics and temperature measurement optimization of the system are experimentally investigated and verified in practical applications.The results show that,firstly,the effects of coal pile heat production power and burial depth,along with heat pipe startup and heat transfer characteristics.At 60 cmburial depth,the condensation section dissipates 98%coal pile heat via natural convection.Secondly,for the temperature measurement error caused by the heat pipe heat transfer temperature difference,the correction method of“superimposing the measured value with the heat transfer temperature difference”is proposed,and the higher the coal temperature,the better the temperature measurement accuracy.Finally,the system can quickly(≤1 h)reduce the temperature of the coal pile to the spontaneous combustion point,significantly inhibiting the spontaneous combustion phenomenon,the maximum temperature does not exceed 49.2℃.Meanwhile,it utilizes waste heat to drive thermoelectric power generation,realizing self-supplied,unattended,and long-term accurate temperature measurement and warning.In a word,synergistic active heat dissipation and self-powered temperature monitoring-warning ensure dual coal pile thermal safety.展开更多
Case study of 2D/3D association and feature based parametric variational design techniques applied to piping system in AEC industry is made to integrate the P&ID and 3D piping modules. Object classes shared by bot...Case study of 2D/3D association and feature based parametric variational design techniques applied to piping system in AEC industry is made to integrate the P&ID and 3D piping modules. Object classes shared by both modules contain the identical connectivity information for all pipelines, while the geometric information for 2D and 3D cases are stored separately. Some details about the object-oriented techniques to cope with such a situation are explored.展开更多
The filling and solidification of a malleable iron pipe casting manufactured by DISA casting mold line with different design parameters were calculated by using software MAGMASOFT. Then the shrinkage porosity was pred...The filling and solidification of a malleable iron pipe casting manufactured by DISA casting mold line with different design parameters were calculated by using software MAGMASOFT. Then the shrinkage porosity was predicted by thermal criterion. Based on the simulation results, the influences of the runner ratio and feeder position on the porosity were discussed. The results show that synchronization of injection can be significantly influenced by the size of downsprue section, and an de-sign structure of DISA gating system was used to solve the problem of flow imbalance in the filling procegs. At the same time, the riser was designed on the hotspot for feeding shrinkage. At last, the optimizated gating system and feeding system were ac-complished to eliminate shrinkage porosity.展开更多
This study investigates the enhancement of convective heat transfer in a serpentine pipe using ferrofluid flow influenced by dual non-uniform magnetic sources.The primary objective is to improve thermal performance in...This study investigates the enhancement of convective heat transfer in a serpentine pipe using ferrofluid flow influenced by dual non-uniform magnetic sources.The primary objective is to improve thermal performance in compact cooling systems,such as those used in heat exchangers.A two-dimensional,steady-state Computational Fluid Dynamic(CFD)model is developed in ANSYS Fluent to simulate the behavior of an incompressible ferrofluid under applied constant heat flux and magnetic fields.The magnetic force is modeled using the Kelvin force,which acts on magnetized nanoparticles in response to spatially varying electromagnetic fields generated by two strategically positioned current-carrying wires.The effects of magnetic field strength,quantified by the magnetic number(Mn),on flow behavior and temperature distribution are thoroughly analyzed.The results indicate that increasing Mn leads to higher Nusselt numbers,demonstrating enhanced convective heat transfer.Secondary vortices induced by magnetic forcing improve fluid mixing,particularly in curved regions of the pipe.A mesh-independence study and model validation with benchmark data support the reliability of the numerical framework.This work highlights the potential of magnetic-field-assisted thermal control in energy-efficient cooling applications and provides a foundation for the further development of advanced ferrofluid-based heat transfer systems.展开更多
Centrifugal casting of ductile iron pipe is a high-temperature,semi-continuous production process.However,conducting laboratory research on the solidification process of centrifugal casting of ductile iron pipe presen...Centrifugal casting of ductile iron pipe is a high-temperature,semi-continuous production process.However,conducting laboratory research on the solidification process of centrifugal casting of ductile iron pipe presents significant challenges.In this study,a novel research method was introduced for investigating the solidification process of ductile iron pipe,namely thermal simulation of ductile iron pipe.Comparative research was conducted on the microstructure and properties of the thermal simulation sample and the ductile iron pipe.The findings indicate that the thermal simulation sample and ductile iron pipe exhibit good heat transfer similarity and microstructure similarity.The difference of cooling rate between thermal simulation sample and ductile pipe is less than 0.24℃·s^(-1),and the difference of microstructure content of free cementite,ferrite,and pearlite is less than 5%.The tensile strength of annealed ductile iron pipe is 466 MPa,with an elongation of 16.1%and a Brinell hardness of 156.5 HBW.In comparison,the tensile strength of annealed thermal simulation sample is 482.0 MPa,with an elongation of 15.5%and a Brinell hardness of 159.0 HBW.These results suggest that the thermal simulation experimental research method is both scientific and feasible,offering an objective,reliable,and cost-effective approach to laboratory research on ductile iron pipe.展开更多
Uncertain parameters are widespread in engineering systems.This study investigates the modal analysis of a fluid-conveying pipe subjected to elastic supports with unknown-but-bound parameters.The governing equation fo...Uncertain parameters are widespread in engineering systems.This study investigates the modal analysis of a fluid-conveying pipe subjected to elastic supports with unknown-but-bound parameters.The governing equation for the elastically supported fluid-conveying pipe is transformed into ordinary differential equations using the Galerkin truncation method.The Chebyshev interval approach,integrated with the assumed mode method is then used to investigate the effects of uncertainties of support stiffness,fluid speed,and pipe length on the natural frequencies and mode shapes of the pipe.Additionally,both symmetrical and asymmetrical support stiffnesses are discussed.The accuracy and effectiveness of the Chebyshev interval approach are verified through comparison with the Monte Carlo method.The results reveal that,for the same deviation coefficient,uncertainties in symmetrical support stiffness have a greater impact on the first four natural frequencies than those of the asymmetrical one.There may be significant differences in the sensitivity of natural frequencies and mode shapes of the same order to uncertain parameters.Notably,mode shapes susceptible to uncertain parameters exhibit wider fluctuation intervals near the elastic supports,requiring more attention.展开更多
As a controllable power generation method requiring no energy storage,Ocean Thermal Energy Conversion(OTEC)technology demonstrates characteristics of abundant reserves,low pollution,and round-the-clock stable operatio...As a controllable power generation method requiring no energy storage,Ocean Thermal Energy Conversion(OTEC)technology demonstrates characteristics of abundant reserves,low pollution,and round-the-clock stable operation.The free-standing cold-water pipe(CWP)in the system withstands various complex loads during operation,posing potential failure risks.To reveal the deformation and stress mechanisms of OTEC CWPs,this study first analyzes wave particle velocity and acceleration to determine wave loads at different water depths.Based on the Euler-Bernoulli beam model,a quasi-static load calculation model for OTEC CWPs was established.The governing equations were discretized using the finite difference method,and matrix equations were solved to analyze bending deformation,bending moments,and surface stresses at discrete points along the pipe.Results indicate that water depths within 50 m represent a critical zone where wave particle velocity,acceleration,and wave loads exhibit significant variations in harmonic patterns,while beyond 50 m depth wave loads decrease linearly.Ocean currents and surface wind-driven currents substantially influence the CWP’s lateral displacement.Considering the effect of clump weights,the maximum lateral displacement occurs at 600–800 m below sea level.Utilizing large-wall-thickness high-strength pipes at the top section significantly enhances the structural safety of the CWP system.展开更多
Fractures are typically characterized by roughness that significantlyaffects the mechanical and hydraulic characteristics of reservoirs.However,hydraulic fracturing mechanisms under the influenceof fracture morphology...Fractures are typically characterized by roughness that significantlyaffects the mechanical and hydraulic characteristics of reservoirs.However,hydraulic fracturing mechanisms under the influenceof fracture morphology remain largely unexplored.Leveraging the advantages of the finite-discrete element method(FDEM)for explicitly simulating fracture propagation and the strengths of the unifiedpipe model(UPM)for efficientlymodeling dual-permeability seepage,we propose a new hydromechanical(HM)coupling approach for modeling hydraulic fracturing.Validated against benchmark examples,the proposed FDEM-UPM model is further augmented by incorporating a Fourier-based methodology for reconstructing non-planar fractures,enabling quantitative analysis of hydraulic fracturing behavior within rough discrete fracture networks(DFNs).The FDEM-UPM model demonstrates computational advantages in accurately capturing transient hydraulic seepage phenomena,while the asynchronous time-stepping schemes between hydraulic and mechanical analyses substantially enhanced computational efficiencywithout compromising computational accuracy.Our results show that fracture morphology can affect both macroscopic fracture networks and microscopic interaction types between hydraulic fractures(HFs)and natural fractures(NFs).In an isotropic stress field,the initiation azimuth,propagation direction and microcracking mechanism are significantly influencedby fracture roughness.In an anisotropic stress field,HFs invariably propagate parallel to the direction of the maximum principal stress,reducing the overall complexity of the stimulated fracture networks.Additionally,stress concentration and perturbation attributed to fracture morphology tend to be compromised as the leak-off increases,while the breakdown and propagation pressures remain insensitive to fracture morphology.These findingsprovide new insights into the hydraulic fracturing mechanisms of fractured reservoirs containing complex rough DFNs.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11632003,11972083,11991030,12372088,and U22B2078)Beijing Institute of Technology Research Fund Program for Young Scholars(Grant No.XSQD-202101010).
文摘The sound field driven by piping systems in enclosures may severely affect living comfort,which is frequently encountered in various engineering applications.Managing this sound field relies heavily on the available prediction tools at hand,e.g.,the widely used finite element methods are computationally expensive due to the necessity to discretize entire space,analytical models,based on modal expansion method,may offer substantial advantages in terms of computational cost and efficiency.However,deriving eigenmodes of irregular enclosed spaces may be challenging,which impedes accurate and rapid predictions of the sound field in practical applications.This study presents an analytical framework aimed at rapidly and accurately predicting the interior sound field driven by the piping system vibrations in irregular enclosures.Vibration response of the piping system is obtained using the wave approach,and a line dipole source is idealized as the sound source of the piping system vibration.On the basis of eigenmodes of regular enclosures,the Kirchhoff-Helmholtz integral theorem(modal ex-pansion method for irregular enclosures)is introduced to account for the boundaries of irregular enclosures.This theoretical framework is validated through numerical simulations by finite element method and experiments,demonstrating high accuracy and significant efficiency advantages.The proposed method can be further employed to optimize radiated sound fields by tailoring the impedance of space walls or layout of piping systems.This study provides an efficient tool for predicting radiated sound field in general enclosures driven by vibration of piping systems,paving a new path for indoor acoustical optimization.
文摘This paper aims to evaluate the feasibility of pressure-dependent models in the design of ship piping systems.For this purpose,a complex ship piping system is designed to operate in firefighting and bilge services through jet pumps.The system is solved as pressure-dependent model by the piping system analysis software EPANET and by a mathematical approach involving a piping network model.This results in a functional system that guarantees the recommendable ranges of hydraulic state variables(flow and pressure)and compliance with the rules of ship classification societies.Through this research,the suitability and viability of pressure-dependent models in the simulation of a ship piping system are proven.
基金Project supported by Changwon National University in 2010
文摘Flow distribution in branch piping system is affected by flow characteristics and different geometric variations. Most of the flow distribution studies are performed with one-dimensional analysis to yield overall information only. However, detailed analysis is required to find effects of design parameters on the flow distribution. For this aspect, three-dimensional turbulent flow analysis was performed to assess turbulence model performance and effects of upstream pressure and branch pipe geometry. Three different turbulence models of standard k-e model, realizable k-e model and standard k-co yield similar results, indicating small effects of turbulence models on flow characteristics analysis. Geometric variations include area ratio of main and branch pipes, branch pipe diameter, and connection shape of main and branch pipes. Among these parameters, area ratio and branch diameter and shape show strong effect on flow distribution due to high friction and minor loss. Uniform flow distribution is one of common requirements in the branch piping system and this can be achieved with rather high total loss design.
文摘Augmented Reality(AR)applications can be used to improve tasks and mitigate errors during facilities operation and maintenance.This article presents an AR system for facility management using a three-dimensional(3D)object tracking method.Through spatial mapping,the object of interest,a pipe trap underneath a sink,is tracked and mixed onto the AR visualization.From that,the maintenance steps are transformed into visible and animated instructions.Although some tracking issues related to the component parts were observed,the designed AR application results demonstrated the potential to improve facility management tasks.
文摘The present paper studies the dynamic pehaviour of a complex piping system containing internal fluid flow.A generalized complex modal decomposition method is proposed for modeling the piping structure.A characteristic impedance transfer matrix of piping flow with a frequency-dependent friction is employed for describing the model of fluid flow,which is coupled to the structural model by means of an approach similar to that used in the structural modal synthesis.The coupled model is practicable for the detecting,monitoring,controlling or predicting of piping vibrations,and for the studying of fluid dynamic characteristics under the influence of structural vibration,also for the diagnosticating of the piping system.
文摘The modal analysis of piping system in air conditioner (AC) outdoor unit is essential to investigate the vibration properties of the system. In view of the growing significance of numerical finite element (FE) model for vibration behaviour prediction, the AC piping elastic end support characterization has been explored. The axial and radial stiffness variables (ka, kr1, kr2) of the compressor-piping mounting are obtained and represented by dynamic stiffness of compressor grommet. They are obtained from dynamic load deflection test based on compressor operating condition such as excitation frequency and amplitude. The unknown stiffness variables of the other tube end (chassis-piping mounting) are determined by parameter fine tuning. An experimental modal analysis using impact hammer test has also been employed to determine the vibration properties such as natural frequencies, mode shapes and damping ratio of the piping structures. The modal parameters acquisition using SCADAS mobile acquisition system and LMS Impact Testing software is compared with the corresponding simulated modal properties using Abaqus. Most of the simulated natural frequencies achieve good correlation with the measured frequencies and it is reasonably a good prediction model to predict vibration behaviour of AC piping structures.
文摘Manufacturing of ship piping systems is one of the major production activities in shipbuilding. The schedule of pipe production has an important impact on the master schedule of shipbuilding. In this research, the ITOC concept was introduced to solve the scheduling problems of a piping factory, and an intelligent scheduling system was developed. The system, in which a product model, an operation model, a factory model, and a knowledge database of piping production were integrated, automated the planning process and production scheduling. Details of the above points were discussed. Moreover, an application of the system in a piping factory, which achieved a higher level of performance as measured by tardiness, lead time, and inventory, was demonstrated.
文摘Manufacturing of ship piping system is one of the major production activities in shipbuilding.The schedule of pipe production has an important impact on master schedule of shipbuilding.In this research,the theory of constraints(TOC) concept is introduced to solve the scheduling problems of piping factory,and an intelligent scheduling system is developed.The system integrates a product model,an operation model,a factory model and a knowledge database of piping production and can make the process planning and production scheduling automatically.In the paper,details of above points are discussed.Moreover,an application of the system in a piping factory,which achieves a higher level of performance as measured by tardiness,lead time and inventory,is demonstrated at the end of the paper.
基金funded by the Science and Technology Research Project of Jiangxi Provincial Department of Education(GJJ2404911)the Ministry of Higher Education,Malaysia through the Fundamental Research Grant Scheme:FRGS/1/2024/TK10/UMP/02/15 and Universiti Malaysia Pahang Al-Sultan Abdullah(RDU240117).
文摘To improve the thermal performance and temperature uniformity of battery pack,this paper presents a novel battery thermal management system(BTMS)that integrates oscillating heat pipe(OHP)technology with liquid cooling.The primary innovation of the new hybrid BTMS lies in the use of an OHP with vertically arranged evaporator and condenser,enabling dual heat transfer pathways through liquid cooling plate and OHP.This study experimentally investigates the performance characteristics of the⊥-shaped OHP and hybrid BTMS.Results show that lower filling ratios significantly enhance the OHP’s startup performance but reduce operational stability,with optimal performance achieved at a 26.1%filling ratio.Acetone,as a single working fluid,exhibited superior heat transfer performance under low-load conditions compared to mixed fluids,while the acetone/ethanol mixture,forming a non-azeotropic solution,minimized temperature fluctuations.At 100 W,the⊥-shaped OHP with a horizontally arranged evaporator demonstrated better heat transfer performance than 2D-OHP designs.Compared to a liquid BTMS using water coolant at 280 W,the hybrid BTMS reduced the equivalent thermal resistance(RBTMS)and maximum temperature difference(ΔTmax)by 8.06%and 19.1%,respectively.When graphene nanofluid was used as the coolant in hybrid BTMS,the battery pack’s average temperature(Tb)dropped from 52.2℃ to 47.9℃,with RBTMS andΔTmax decreasing by 20.1%and 32.7%,respectively.These findings underscore the hybrid BTMS’s suitability for high heat load applications,offering a promising solution for electric vehicle thermal management.
文摘Industry and energy continue to require piston engines(PICE)at a high level worldwide.Therefore,science and technology must urgently work on improving the PICE working cycle.Improving the quality of the intake process of theworking fluid into the cylinder is one of the most effective ways to improve the operational performance of PICE.The purpose of the study was to assess the impact of various cylinder head(CylH)designs on the gas-dynamic and heat-exchange qualities of air flows within an engine model’s intake system.Three different CylH designs were studied:the basic configuration and upgraded cylinder heads with a square valve and a square valve port.These designs are innovative.Laboratory conditions were used to conduct the studies for stationary air flow.The experiments covered the range of Reynolds numbers from 8500 to 96,000.The intake system’s gas dynamics and heat transfer were determined using the thermal anemometry method,which was based on constant-temperature hot-wire anemometers.It has been established that the use of upgraded CylHs causes an increase in the turbulence number of flow by an average of 13.5%.Additionally,itwas found that the increase in the turbulence number of flowin the cylinder is about 19%when installing new CylH designs.It was shown that therewas an increase in the heat transfer coefficient in the intake pipe by 10%–40%when installing modernized CylH designs in the intake system.The article focused on the problems of increasing the turbulence level and intensifying the heat transfer of stationary air flow in the intake system,specifically in PICEs.The study’s findings are novel in the areas of applied gas dynamics and PICEs.
基金National Recovery and Resilience Plan(NRRP)Mission 4 Component 2 Investment 1.5-Call for tender No.3277 of 30/12/2021 of Italian Ministry of University and Research funded by the European Union-NextGenerationEU(Award Number:Project code ECS00000033,Concession Decree No.1052 of 23 June 2022 adopted by the Italian Ministry of,CUP D93C22000460001,“Ecosystem for Sustainable Transition in Emilia-Romagna”(Ecosister)).
文摘This study investigates the feasibility of a novel dual two-phase cooling system for thermal management in lithium-ion batteries used in electric vehicles(EVs).The proposed system aims to combine low-boiling dielectric fluid immersion cooling and pulsating heat pipes(PHPs),in order to leverage the advantages of both technologies for efficient heat dissipation in a completely passive configuration.Experimental evaluations conducted under different discharge conditions demonstrate that the systemeffectivelymaintains battery temperatureswithin the optimal range of 20–40℃,with enhanced temperature uniformity and stability.While the PHP exhibited minimal impact at low power,its role became critical under higher discharge rates,ensuring efficient vapor condensation and pressure stability.The results highlight the potential of this passive cooling system to improve battery performance and safety,supporting its application in EV battery thermal management.Future work aims to optimize design parameters and evaluate real battery modules under ultra-fast charging scenarios.
基金Project supported by the National Natural Science Foundation of China (No. 12272323)。
文摘The double-beam system is a crucial foundational structure in industry,with extensive application contexts and significant research value.The double-beam system with damping and gyroscopic effects is termed as the damped gyroscopic double-beam system.In such systems,the orthogonality conditions of the undamped double-beam system are no longer applicable,rendering it impossible to decouple them in modal space using the modal superposition method(MSM) to obtain analytical solutions.Based on the complex modal method and state space method,this paper takes the damped pipe-in-pipe(PIP) system as an example to solve this problem.The concepts of the original system and adjoint system are introduced,and the orthogonality conditions of the damped PIP system are given in the state-space.Based on the derived orthogonality conditions,the transient and steady-state response solutions are obtained.In the numerical discussion section,the convergence and accuracy of the solutions are verified.In addition,the dynamic responses of the system under different excitations and initial conditions are studied,and the forward and reverse synchronous vibrations in the PIP system are discussed.Overall,the method presented in this paper provides a convenient way to analyze the dynamics of the damped gyroscopic double-beam system.
基金supported by the Engineering Research Centre for Digital Grid Technology for Coordinating New Energy under Grant[Grant number 2021GCZX003]Yunnan Fundamental Research Projects under Grant[Grant number 202301CF070031]+2 种基金Hundred Talents Project 2023 under Grant[Grant number B0201001]2024 Distinctive Innovation Scientific Research Projects for Higher Education Institutions[Grant number 2024KTSCX157]Young Innovative Talent Project under Grant[Grant numbers K0223021,K0224014].
文摘Targeting spontaneous coal combustion during stacking,we developed an efficient heat dissipation&self-supplied wireless temperature measurement system(SPWTM)with gravity heat pipe-thermoelectric integration for dual safety.The heat transfer characteristics and temperature measurement optimization of the system are experimentally investigated and verified in practical applications.The results show that,firstly,the effects of coal pile heat production power and burial depth,along with heat pipe startup and heat transfer characteristics.At 60 cmburial depth,the condensation section dissipates 98%coal pile heat via natural convection.Secondly,for the temperature measurement error caused by the heat pipe heat transfer temperature difference,the correction method of“superimposing the measured value with the heat transfer temperature difference”is proposed,and the higher the coal temperature,the better the temperature measurement accuracy.Finally,the system can quickly(≤1 h)reduce the temperature of the coal pile to the spontaneous combustion point,significantly inhibiting the spontaneous combustion phenomenon,the maximum temperature does not exceed 49.2℃.Meanwhile,it utilizes waste heat to drive thermoelectric power generation,realizing self-supplied,unattended,and long-term accurate temperature measurement and warning.In a word,synergistic active heat dissipation and self-powered temperature monitoring-warning ensure dual coal pile thermal safety.
文摘Case study of 2D/3D association and feature based parametric variational design techniques applied to piping system in AEC industry is made to integrate the P&ID and 3D piping modules. Object classes shared by both modules contain the identical connectivity information for all pipelines, while the geometric information for 2D and 3D cases are stored separately. Some details about the object-oriented techniques to cope with such a situation are explored.
文摘The filling and solidification of a malleable iron pipe casting manufactured by DISA casting mold line with different design parameters were calculated by using software MAGMASOFT. Then the shrinkage porosity was predicted by thermal criterion. Based on the simulation results, the influences of the runner ratio and feeder position on the porosity were discussed. The results show that synchronization of injection can be significantly influenced by the size of downsprue section, and an de-sign structure of DISA gating system was used to solve the problem of flow imbalance in the filling procegs. At the same time, the riser was designed on the hotspot for feeding shrinkage. At last, the optimizated gating system and feeding system were ac-complished to eliminate shrinkage porosity.
文摘This study investigates the enhancement of convective heat transfer in a serpentine pipe using ferrofluid flow influenced by dual non-uniform magnetic sources.The primary objective is to improve thermal performance in compact cooling systems,such as those used in heat exchangers.A two-dimensional,steady-state Computational Fluid Dynamic(CFD)model is developed in ANSYS Fluent to simulate the behavior of an incompressible ferrofluid under applied constant heat flux and magnetic fields.The magnetic force is modeled using the Kelvin force,which acts on magnetized nanoparticles in response to spatially varying electromagnetic fields generated by two strategically positioned current-carrying wires.The effects of magnetic field strength,quantified by the magnetic number(Mn),on flow behavior and temperature distribution are thoroughly analyzed.The results indicate that increasing Mn leads to higher Nusselt numbers,demonstrating enhanced convective heat transfer.Secondary vortices induced by magnetic forcing improve fluid mixing,particularly in curved regions of the pipe.A mesh-independence study and model validation with benchmark data support the reliability of the numerical framework.This work highlights the potential of magnetic-field-assisted thermal control in energy-efficient cooling applications and provides a foundation for the further development of advanced ferrofluid-based heat transfer systems.
基金financially supported by the National Natural Science Foundation of China(52130109)。
文摘Centrifugal casting of ductile iron pipe is a high-temperature,semi-continuous production process.However,conducting laboratory research on the solidification process of centrifugal casting of ductile iron pipe presents significant challenges.In this study,a novel research method was introduced for investigating the solidification process of ductile iron pipe,namely thermal simulation of ductile iron pipe.Comparative research was conducted on the microstructure and properties of the thermal simulation sample and the ductile iron pipe.The findings indicate that the thermal simulation sample and ductile iron pipe exhibit good heat transfer similarity and microstructure similarity.The difference of cooling rate between thermal simulation sample and ductile pipe is less than 0.24℃·s^(-1),and the difference of microstructure content of free cementite,ferrite,and pearlite is less than 5%.The tensile strength of annealed ductile iron pipe is 466 MPa,with an elongation of 16.1%and a Brinell hardness of 156.5 HBW.In comparison,the tensile strength of annealed thermal simulation sample is 482.0 MPa,with an elongation of 15.5%and a Brinell hardness of 159.0 HBW.These results suggest that the thermal simulation experimental research method is both scientific and feasible,offering an objective,reliable,and cost-effective approach to laboratory research on ductile iron pipe.
基金supported by the National Natural Science Foundation of China(Grant Nos.12272211,12072181,and 12121002).
文摘Uncertain parameters are widespread in engineering systems.This study investigates the modal analysis of a fluid-conveying pipe subjected to elastic supports with unknown-but-bound parameters.The governing equation for the elastically supported fluid-conveying pipe is transformed into ordinary differential equations using the Galerkin truncation method.The Chebyshev interval approach,integrated with the assumed mode method is then used to investigate the effects of uncertainties of support stiffness,fluid speed,and pipe length on the natural frequencies and mode shapes of the pipe.Additionally,both symmetrical and asymmetrical support stiffnesses are discussed.The accuracy and effectiveness of the Chebyshev interval approach are verified through comparison with the Monte Carlo method.The results reveal that,for the same deviation coefficient,uncertainties in symmetrical support stiffness have a greater impact on the first four natural frequencies than those of the asymmetrical one.There may be significant differences in the sensitivity of natural frequencies and mode shapes of the same order to uncertain parameters.Notably,mode shapes susceptible to uncertain parameters exhibit wider fluctuation intervals near the elastic supports,requiring more attention.
基金funded by Nansha District Science and Technology Project(Grant Number.2024ZD008)funded by China Geological Survey(Grant number:No.DD20230066,DD20242659).
文摘As a controllable power generation method requiring no energy storage,Ocean Thermal Energy Conversion(OTEC)technology demonstrates characteristics of abundant reserves,low pollution,and round-the-clock stable operation.The free-standing cold-water pipe(CWP)in the system withstands various complex loads during operation,posing potential failure risks.To reveal the deformation and stress mechanisms of OTEC CWPs,this study first analyzes wave particle velocity and acceleration to determine wave loads at different water depths.Based on the Euler-Bernoulli beam model,a quasi-static load calculation model for OTEC CWPs was established.The governing equations were discretized using the finite difference method,and matrix equations were solved to analyze bending deformation,bending moments,and surface stresses at discrete points along the pipe.Results indicate that water depths within 50 m represent a critical zone where wave particle velocity,acceleration,and wave loads exhibit significant variations in harmonic patterns,while beyond 50 m depth wave loads decrease linearly.Ocean currents and surface wind-driven currents substantially influence the CWP’s lateral displacement.Considering the effect of clump weights,the maximum lateral displacement occurs at 600–800 m below sea level.Utilizing large-wall-thickness high-strength pipes at the top section significantly enhances the structural safety of the CWP system.
基金supported by the National Natural Science Foundation of China(Grant Nos.52574103 and 42277150).
文摘Fractures are typically characterized by roughness that significantlyaffects the mechanical and hydraulic characteristics of reservoirs.However,hydraulic fracturing mechanisms under the influenceof fracture morphology remain largely unexplored.Leveraging the advantages of the finite-discrete element method(FDEM)for explicitly simulating fracture propagation and the strengths of the unifiedpipe model(UPM)for efficientlymodeling dual-permeability seepage,we propose a new hydromechanical(HM)coupling approach for modeling hydraulic fracturing.Validated against benchmark examples,the proposed FDEM-UPM model is further augmented by incorporating a Fourier-based methodology for reconstructing non-planar fractures,enabling quantitative analysis of hydraulic fracturing behavior within rough discrete fracture networks(DFNs).The FDEM-UPM model demonstrates computational advantages in accurately capturing transient hydraulic seepage phenomena,while the asynchronous time-stepping schemes between hydraulic and mechanical analyses substantially enhanced computational efficiencywithout compromising computational accuracy.Our results show that fracture morphology can affect both macroscopic fracture networks and microscopic interaction types between hydraulic fractures(HFs)and natural fractures(NFs).In an isotropic stress field,the initiation azimuth,propagation direction and microcracking mechanism are significantly influencedby fracture roughness.In an anisotropic stress field,HFs invariably propagate parallel to the direction of the maximum principal stress,reducing the overall complexity of the stimulated fracture networks.Additionally,stress concentration and perturbation attributed to fracture morphology tend to be compromised as the leak-off increases,while the breakdown and propagation pressures remain insensitive to fracture morphology.These findingsprovide new insights into the hydraulic fracturing mechanisms of fractured reservoirs containing complex rough DFNs.
