As a core power device in strategic industries such as new energy power generation and electric vehicles,the thermal reliability of IGBT modules directly determines the performance and lifetime of the whole system.A s...As a core power device in strategic industries such as new energy power generation and electric vehicles,the thermal reliability of IGBT modules directly determines the performance and lifetime of the whole system.A synergistic optimization structure of“inlet plate-channel spoiler columns”is proposed for the local hot spot problem during the operation of Insulated Gate Bipolar Transistor(IGBT),combined with the inherent defect of uneven flow distribution of the traditional U-type liquid cooling plate in this paper.The influences of the shape,height(H),and spacing from the spoiler column(b)of the plate on the comprehensive heat dissipation performance of the liquid cooling plate are analyzed at different Reynolds numbers,A dual heat source strategy is introduced and the effect of the optimized structure is evaluated by the temperature inhomogeneity coefficient(Φ).The results show that the optimum effect is achieved when the shape of the plate is square,H=4.5 mm,b=2 mm,and u=0.05 m/s,at which the HTPE=1.09 and Φ are reduced by 40%.In contrast,the maximum temperatures of the IGBT and the FWD(Free Wheeling Diode)chips are reduced by 8.7 and 8.4 K,respectively,and ΔP rises by only 1.58 Pa while keeping ΔT not significantly increased.This optimized configuration achieves a significant reduction in the critical chip temperature and optimization of the flow field uniformity with almost no change in the system flow resistance.It breaks through the limitation of single structure optimization of the traditional liquid cooling plate and effectively solves the problem of uneven flow in the U-shaped cooling plate,which provides a new solution with important engineering value for the thermal management of IGBT modules.展开更多
In this study, a microchannel liquid cooling plate (LCP) is proposed for Intel Xeon 52.5 mm * 45 mm packaged architecture processors based on topology optimization (TO). Firstly, a mathematical model for topology opti...In this study, a microchannel liquid cooling plate (LCP) is proposed for Intel Xeon 52.5 mm * 45 mm packaged architecture processors based on topology optimization (TO). Firstly, a mathematical model for topology optimization design of the LCP is established based on heat dissipation and pressure drop objectives. We obtain a series of two-dimensional (2D) topology optimization configurations with different weighting factors for two objectives. It is found that the biomimetic phenomenon of the topologically optimized flow channel structure is more pronounced at low Reynolds numbers. Secondly, the topology configuration is stretched into a three-dimensional (3D) model to perform CFD simulations under actual operating conditions. The results show that the thermal resistance and pressure drop of the LCP based on topology optimization achieve a reduction of approximately 20% - 50% compared to traditional serpentine and microchannel straight flow channel structures. The Nusselt number can be improved by up to 76.1% compared to microchannel straight designs. Moreover, it is observed that under high flow rates, straight microchannel LCPs exhibit significant backflow, vortex phenomena, and topology optimization structures LCPs also tend to lead to loss of effectiveness in the form of tree root-shaped branch flows. Suitable flow rate ranges for LCPs are provided. Furthermore, the temperature and pressure drop of experimental results are consistent with the numerical ones, which verifies the effectiveness of performance for topology optimization flow channel LCP.展开更多
An electrochemical thermal coupling model of lithium battery was established to study the heat generation characteristic in this study.The simulation results showed that the heat generation density of the battery incr...An electrochemical thermal coupling model of lithium battery was established to study the heat generation characteristic in this study.The simulation results showed that the heat generation density of the battery increased with the discharge rate.With the discharge process,the heat generation density of the battery increased continuously.With 2.5C discharge rate,the heat generation density at the end of discharge was 1.82 times of that at the beginning of discharge.The heat generation density at different areas of the battery was not uniform and 46%of the total ohmic heat was generated near the electrode tabs.A cooling plate with variable mini-channels was designed to improve the temperature non-uniformity caused by the heat generation characteristic.A cooling plate with uniform mini-channels was designed for compared experiment.The experiments were conducted with deionized water and refrigerant R141b and carried out with 1.5C,2C and 2.5C discharge rates.Experimental results showed that the cooling plate with variable mini-channels had a better cooling performance in both single-phase and two-phase cooling conditions.展开更多
To ensure the battery works in a suitable temperature range,a new design for distributed liquid cooling plate is proposed,and a battery thermal management system(BTMS)for cylindrical power battery pack based on the pr...To ensure the battery works in a suitable temperature range,a new design for distributed liquid cooling plate is proposed,and a battery thermal management system(BTMS)for cylindrical power battery pack based on the proposed cooling plate is also investigated.To verify the accuracy of the battery model and battery pack numerical calculation model used for simulation,an experiment is conducted for the liquid cooling BTMS.The influence of key working parameters,including the cooling water inlet flow,ambient temperature and working conditions,are investigated.The results show that at the discharge rate of 3 C,the best cooling performance can be achieved when the total inlet mass flow rate is 3.2 g/s and the flow distribution is 3:1:1:3.The obtained maximum temperature is 29.6℃ and the maximum temperature difference is 2.1℃.When the ambient temperature is in the range of 20℃ to 50℃,the proposed BTMS can keep the temperature of battery pack in the proper range.Finally,different inlet flow rates are recommended according to different battery working states.展开更多
A356 alloy melt solidifies partially when it flows down on an oblique plate cooled from bottom by counter flowing water. Columnar dendrites are continuously formed on the plate wall. Because of the forced convection, ...A356 alloy melt solidifies partially when it flows down on an oblique plate cooled from bottom by counter flowing water. Columnar dendrites are continuously formed on the plate wall. Because of the forced convection, these dendrites are sheared off into equiaxed/fragmented grains and then washed away continuously by producing semisolid slurry at plate exit. Plate cooling rate provides required extent/amount of solidification whereas plate length enables necessary shear for producing semisolid slurry of desired quality. Slurry obtained is solidified in metal mould to produce semisolid-cast billets of desired microstructure. Furthermore, semisolid-cast billets are also heat-treated to improve surface quality. Microstructures of both semisolid-cast and heat-treated billets are compared. The effects of plate length and plate cooling rate on solidification and microstructure of billets produced by using oblique plate are illustrated. Three different plate lengths（200 mm, 250 mm, 300 mm） associated with three different heat transfer coefficients（1000, 2000 and 2500 W/（m2·K）） are involved. Plate length of 250 mm with heat transfer coefficient of 2000 W/（m2·K） gives fine and globular microstructures and is the optimum as there is absolutely no possibility of sticking of slurry to plate wall.展开更多
Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind...Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind power generation and other fields. This paper introduces the basic structure of hybrid excitation motor with modular stator, and analyzes the operation principle of hybrid excitation motor. The cooling structure of the water-cooled plate is designed, and the effects of the thickness of the water-cooled plate and the number of water channels in the water-cooled plate on the heat dissipation capacity of the water-cooled plate are analyzed by theoretical and computational fluid dynamics methods. The effects of different water cooling plate structures on water velocity, pressure drop, water pump power consumption and heat dissipation capacity were compared and analyzed. The influence of different inlet flow velocity on the maximum temperature rise of each part of the motor is analyzed, and the temperature of each part of the motor under the optimal water flow is analyzed. The influence of the traditional spiral water jacket cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of the motor components is compared and analyzed. The results show that the water-cooled plate cooling structure is more suitable for the modular stator motor studied in this paper. Based on the water-cooled plate cooling structure, the air-water composite cooling structure is designed, and the effects of the air-water composite cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of each component of the motor are compared and analyzed. The results show that the maximum temperature rise of each component of the motor is reduced under the air-water composite cooling structure.展开更多
We investigated phase transition and precipitation of ultra-high strength steel（UHSS）in a new ＂short process＂ with controlled rolling and controlled cooling.Thermalexpansion test combined with metallographic obser...We investigated phase transition and precipitation of ultra-high strength steel（UHSS）in a new ＂short process＂ with controlled rolling and controlled cooling.Thermalexpansion test combined with metallographic observation was used to research the continuous cooling transformation（CCT）curve.Moreover,the microstructuraltransformation and precipitation law was revealed by morphologicalobservation and alloying elements by electron probe micro-analyzer（EPMA）.Transmission electron microscopy（TEM）was utilized to analyze the composition and grain orientation of microstructure.The study showed that the measured criticaltransformation temperatures of Ac1 and Ac3 were 746 and 868 ℃,respectively.The CCT curve indicated that the undercooled austenite was transformed into proeutectoid ferrite and bainite with HV 520 in a broad range of cooling rate 0.1^（-1） ℃·s^（-1）.When subjected to a cooling rate of 1 ℃·s^（-1）,the undercooled austenite was divided into small-sized blocks by formed martensite.With further increase of cooling rate,micro-hardness increased dramatically,the microstructure of specimen was mainly lathe bainite（LB）,granular bainite（GB）,lath martensite（LM）and residualaustenite.By diffraction test analysis,it was identified that there was K-S orientation relationship between martensite and austenite for {110}_α//{111}_γ,{111}_α//{101}_γ.EPMA clearly showed that carbon diffused adequately due to staying for a long time at high temperature with a lower cooling rate of 2 ℃·s-1.Phase transition drive force was lower and the residualaustenite existed in the block form of Martensite austenite island（M-A）.With the increase of cooling rate to 10 ℃·s^（-1）,the block residualaustenite reduced,the carbon content of residualaustenite increased and α phase around the residualaustenite formed into a low carbon bainite form.展开更多
Casting simulation tool ADSTEFAN is useful to design casting technology of complicated iron castings.Based on the function of solidification analysis,special methods were taken to carry out the prediction and optimiza...Casting simulation tool ADSTEFAN is useful to design casting technology of complicated iron castings.Based on the function of solidification analysis,special methods were taken to carry out the prediction and optimization of shake-out timing for large sized iron castings.It has been proved that these analyses are effective to iron casting production.During the research of cast iron semi-solid process,to predict and control the influence of inclined cooling plate on flow and heat transmission of molten iron,the basis of analysis model has been built in this study.Flow field simulation considering temperature field was carried out for further research and satisfied with the practical production.展开更多
The relation of heat flow and floor depth across the mid-ocean ridges versus lithosphere age can be described by linear functions of square root of age according to plate thermal conductive Half Space Models(HSM).Howe...The relation of heat flow and floor depth across the mid-ocean ridges versus lithosphere age can be described by linear functions of square root of age according to plate thermal conductive Half Space Models(HSM).However,one of the long-standing problems of these classical models is the discrepancies between predicted and observed heat flow and floor depth for very young and very old lithosphere.There have been several recent attempts to overcome this problem:one model incorporates temperature-and pressure-dependent parameters and the second model includes an additional low-conductivity crustal layer or magma rich mantle layer(MRM).Alternatively,in the current paper,the ordinary density of lithosphere in the plate conductive models is substituted with a reduction of lithosphere density towards axis that features the irregularity and nonlinearity of plates across the mid-ocean ridges.A new model is formulated incorporating the new form of density for predicting both peak heat flow and floor depth.Simple solutions of power-law forms derived from the model can significantly improve the predicting results of heat flow and floor depth over the mid-ocean ridges.Several datasets in the literature were reutilized for model validation and comparison.These datasets include both earlier datasets used for original model calibration and the more recently compiled high-quality datasets with both sedimentary and crustal loading corrections.The results indicate that both the heat flow and the slope(first orderderivative)of sea floor approach infinity(undifferentiability or singularities)around the mid-ocean ridges.These singularities are partially due to the boundary condition as it has been already known in the literature and partially to the reduction of density of lithosphere as discovered for the first time in the current research.展开更多
基金supported by Tianjin Science and Technology Planning Project(22YDTPJC0020).
文摘As a core power device in strategic industries such as new energy power generation and electric vehicles,the thermal reliability of IGBT modules directly determines the performance and lifetime of the whole system.A synergistic optimization structure of“inlet plate-channel spoiler columns”is proposed for the local hot spot problem during the operation of Insulated Gate Bipolar Transistor(IGBT),combined with the inherent defect of uneven flow distribution of the traditional U-type liquid cooling plate in this paper.The influences of the shape,height(H),and spacing from the spoiler column(b)of the plate on the comprehensive heat dissipation performance of the liquid cooling plate are analyzed at different Reynolds numbers,A dual heat source strategy is introduced and the effect of the optimized structure is evaluated by the temperature inhomogeneity coefficient(Φ).The results show that the optimum effect is achieved when the shape of the plate is square,H=4.5 mm,b=2 mm,and u=0.05 m/s,at which the HTPE=1.09 and Φ are reduced by 40%.In contrast,the maximum temperatures of the IGBT and the FWD(Free Wheeling Diode)chips are reduced by 8.7 and 8.4 K,respectively,and ΔP rises by only 1.58 Pa while keeping ΔT not significantly increased.This optimized configuration achieves a significant reduction in the critical chip temperature and optimization of the flow field uniformity with almost no change in the system flow resistance.It breaks through the limitation of single structure optimization of the traditional liquid cooling plate and effectively solves the problem of uneven flow in the U-shaped cooling plate,which provides a new solution with important engineering value for the thermal management of IGBT modules.
文摘In this study, a microchannel liquid cooling plate (LCP) is proposed for Intel Xeon 52.5 mm * 45 mm packaged architecture processors based on topology optimization (TO). Firstly, a mathematical model for topology optimization design of the LCP is established based on heat dissipation and pressure drop objectives. We obtain a series of two-dimensional (2D) topology optimization configurations with different weighting factors for two objectives. It is found that the biomimetic phenomenon of the topologically optimized flow channel structure is more pronounced at low Reynolds numbers. Secondly, the topology configuration is stretched into a three-dimensional (3D) model to perform CFD simulations under actual operating conditions. The results show that the thermal resistance and pressure drop of the LCP based on topology optimization achieve a reduction of approximately 20% - 50% compared to traditional serpentine and microchannel straight flow channel structures. The Nusselt number can be improved by up to 76.1% compared to microchannel straight designs. Moreover, it is observed that under high flow rates, straight microchannel LCPs exhibit significant backflow, vortex phenomena, and topology optimization structures LCPs also tend to lead to loss of effectiveness in the form of tree root-shaped branch flows. Suitable flow rate ranges for LCPs are provided. Furthermore, the temperature and pressure drop of experimental results are consistent with the numerical ones, which verifies the effectiveness of performance for topology optimization flow channel LCP.
基金supported by the National Key R&D Program of China(2019YFE0104900)。
文摘An electrochemical thermal coupling model of lithium battery was established to study the heat generation characteristic in this study.The simulation results showed that the heat generation density of the battery increased with the discharge rate.With the discharge process,the heat generation density of the battery increased continuously.With 2.5C discharge rate,the heat generation density at the end of discharge was 1.82 times of that at the beginning of discharge.The heat generation density at different areas of the battery was not uniform and 46%of the total ohmic heat was generated near the electrode tabs.A cooling plate with variable mini-channels was designed to improve the temperature non-uniformity caused by the heat generation characteristic.A cooling plate with uniform mini-channels was designed for compared experiment.The experiments were conducted with deionized water and refrigerant R141b and carried out with 1.5C,2C and 2.5C discharge rates.Experimental results showed that the cooling plate with variable mini-channels had a better cooling performance in both single-phase and two-phase cooling conditions.
基金supported by the National Natural Science Foundation of China(Grant No.52076163)。
文摘To ensure the battery works in a suitable temperature range,a new design for distributed liquid cooling plate is proposed,and a battery thermal management system(BTMS)for cylindrical power battery pack based on the proposed cooling plate is also investigated.To verify the accuracy of the battery model and battery pack numerical calculation model used for simulation,an experiment is conducted for the liquid cooling BTMS.The influence of key working parameters,including the cooling water inlet flow,ambient temperature and working conditions,are investigated.The results show that at the discharge rate of 3 C,the best cooling performance can be achieved when the total inlet mass flow rate is 3.2 g/s and the flow distribution is 3:1:1:3.The obtained maximum temperature is 29.6℃ and the maximum temperature difference is 2.1℃.When the ambient temperature is in the range of 20℃ to 50℃,the proposed BTMS can keep the temperature of battery pack in the proper range.Finally,different inlet flow rates are recommended according to different battery working states.
基金financial support received from Ministry of Mines, TIFAC, and Department of Science and Technology
文摘A356 alloy melt solidifies partially when it flows down on an oblique plate cooled from bottom by counter flowing water. Columnar dendrites are continuously formed on the plate wall. Because of the forced convection, these dendrites are sheared off into equiaxed/fragmented grains and then washed away continuously by producing semisolid slurry at plate exit. Plate cooling rate provides required extent/amount of solidification whereas plate length enables necessary shear for producing semisolid slurry of desired quality. Slurry obtained is solidified in metal mould to produce semisolid-cast billets of desired microstructure. Furthermore, semisolid-cast billets are also heat-treated to improve surface quality. Microstructures of both semisolid-cast and heat-treated billets are compared. The effects of plate length and plate cooling rate on solidification and microstructure of billets produced by using oblique plate are illustrated. Three different plate lengths（200 mm, 250 mm, 300 mm） associated with three different heat transfer coefficients（1000, 2000 and 2500 W/（m2·K）） are involved. Plate length of 250 mm with heat transfer coefficient of 2000 W/（m2·K） gives fine and globular microstructures and is the optimum as there is absolutely no possibility of sticking of slurry to plate wall.
基金supported by the National Natural Science Foundation of China (51907129)Project Supported by Department of Science and Technology of Liaoning Province (2021-MS-236)。
文摘Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind power generation and other fields. This paper introduces the basic structure of hybrid excitation motor with modular stator, and analyzes the operation principle of hybrid excitation motor. The cooling structure of the water-cooled plate is designed, and the effects of the thickness of the water-cooled plate and the number of water channels in the water-cooled plate on the heat dissipation capacity of the water-cooled plate are analyzed by theoretical and computational fluid dynamics methods. The effects of different water cooling plate structures on water velocity, pressure drop, water pump power consumption and heat dissipation capacity were compared and analyzed. The influence of different inlet flow velocity on the maximum temperature rise of each part of the motor is analyzed, and the temperature of each part of the motor under the optimal water flow is analyzed. The influence of the traditional spiral water jacket cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of the motor components is compared and analyzed. The results show that the water-cooled plate cooling structure is more suitable for the modular stator motor studied in this paper. Based on the water-cooled plate cooling structure, the air-water composite cooling structure is designed, and the effects of the air-water composite cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of each component of the motor are compared and analyzed. The results show that the maximum temperature rise of each component of the motor is reduced under the air-water composite cooling structure.
基金Funded by the Scientifi c and Technological Research Program of Chongqing Municipal Education Commission(No.KJ1501324)the General Project of Chongqing Frontier and Applied Basic Research Project(No.cstc2015jcyj A90005)the Research Foundation of Chongqing University of Science and Technology(Nos.CK2013Z16&CK2014Z20)
文摘We investigated phase transition and precipitation of ultra-high strength steel（UHSS）in a new ＂short process＂ with controlled rolling and controlled cooling.Thermalexpansion test combined with metallographic observation was used to research the continuous cooling transformation（CCT）curve.Moreover,the microstructuraltransformation and precipitation law was revealed by morphologicalobservation and alloying elements by electron probe micro-analyzer（EPMA）.Transmission electron microscopy（TEM）was utilized to analyze the composition and grain orientation of microstructure.The study showed that the measured criticaltransformation temperatures of Ac1 and Ac3 were 746 and 868 ℃,respectively.The CCT curve indicated that the undercooled austenite was transformed into proeutectoid ferrite and bainite with HV 520 in a broad range of cooling rate 0.1^（-1） ℃·s^（-1）.When subjected to a cooling rate of 1 ℃·s^（-1）,the undercooled austenite was divided into small-sized blocks by formed martensite.With further increase of cooling rate,micro-hardness increased dramatically,the microstructure of specimen was mainly lathe bainite（LB）,granular bainite（GB）,lath martensite（LM）and residualaustenite.By diffraction test analysis,it was identified that there was K-S orientation relationship between martensite and austenite for {110}_α//{111}_γ,{111}_α//{101}_γ.EPMA clearly showed that carbon diffused adequately due to staying for a long time at high temperature with a lower cooling rate of 2 ℃·s-1.Phase transition drive force was lower and the residualaustenite existed in the block form of Martensite austenite island（M-A）.With the increase of cooling rate to 10 ℃·s^（-1）,the block residualaustenite reduced,the carbon content of residualaustenite increased and α phase around the residualaustenite formed into a low carbon bainite form.
文摘Casting simulation tool ADSTEFAN is useful to design casting technology of complicated iron castings.Based on the function of solidification analysis,special methods were taken to carry out the prediction and optimization of shake-out timing for large sized iron castings.It has been proved that these analyses are effective to iron casting production.During the research of cast iron semi-solid process,to predict and control the influence of inclined cooling plate on flow and heat transmission of molten iron,the basis of analysis model has been built in this study.Flow field simulation considering temperature field was carried out for further research and satisfied with the practical production.
基金supported by National Natural Science Foundation of China(grant number 42050103)Guangdong Research Team Development Grant(grant number 2021ZT09H399)。
文摘The relation of heat flow and floor depth across the mid-ocean ridges versus lithosphere age can be described by linear functions of square root of age according to plate thermal conductive Half Space Models(HSM).However,one of the long-standing problems of these classical models is the discrepancies between predicted and observed heat flow and floor depth for very young and very old lithosphere.There have been several recent attempts to overcome this problem:one model incorporates temperature-and pressure-dependent parameters and the second model includes an additional low-conductivity crustal layer or magma rich mantle layer(MRM).Alternatively,in the current paper,the ordinary density of lithosphere in the plate conductive models is substituted with a reduction of lithosphere density towards axis that features the irregularity and nonlinearity of plates across the mid-ocean ridges.A new model is formulated incorporating the new form of density for predicting both peak heat flow and floor depth.Simple solutions of power-law forms derived from the model can significantly improve the predicting results of heat flow and floor depth over the mid-ocean ridges.Several datasets in the literature were reutilized for model validation and comparison.These datasets include both earlier datasets used for original model calibration and the more recently compiled high-quality datasets with both sedimentary and crustal loading corrections.The results indicate that both the heat flow and the slope(first orderderivative)of sea floor approach infinity(undifferentiability or singularities)around the mid-ocean ridges.These singularities are partially due to the boundary condition as it has been already known in the literature and partially to the reduction of density of lithosphere as discovered for the first time in the current research.
