As the promising cooling method for the next generation of data centers,the internal heat transport mechanism and enhancement mechanism of single-phase immersion liquid-cooled(SPILC)systems are not yet well understood...As the promising cooling method for the next generation of data centers,the internal heat transport mechanism and enhancement mechanism of single-phase immersion liquid-cooled(SPILC)systems are not yet well understood.To address this,a steady-state three-dimensional numerical model is constructed herein to analyze flow and thermal transport capacities in servers using SPILC and traditional air-cooling methods.Moreover,this paper emphasizes the influence of component positioning,and underscores the benefits of optimizing coolant flow distribution using baffles.The results indicate that the SPILC system outperforms the traditional air-cooling approach at the same inlet Reynolds number(Re).When Re=10000,the SPILC method reduces the maximum temperature by up to 70.13%,increases the average convective heat transfer coefficient by287.5%,and provides better overall thermal uniformity in data center servers.Moreover,placing devices downstream of high-power components creates"thermal barriers"and degrades thermal transport for upstream devices due to increased flow resistance.Excessive spacing between high-power devices can lead to the formation of bypass channels,further deteriorating heat transfer.Additionally,the addition of baffles in the inlet section of SPILC systems effectively enhances heat dissipation performance.To maximize the heat dissipation capacity,minimizing bypass channels and optimizing the flow distribution of coolants are crucial.展开更多
The liquid-cooled battery energy sto rage system(LCBESS) has gained significant attention due to its superior thermal management capacity.However,liquid-cooled battery pack(LCBP) usually has a high sealing level above...The liquid-cooled battery energy sto rage system(LCBESS) has gained significant attention due to its superior thermal management capacity.However,liquid-cooled battery pack(LCBP) usually has a high sealing level above IP65,which can trap flammable and explosive gases from battery thermal runaway and cause explosions.This poses serious safety risks and challenges for LCBESS.In this study,we tested overcharged battery inside a commercial LCBP and found that the conventionally mechanical pressure relief valve(PRV) on the LCBP had a delayed response and low-pressure relief efficiency.A realistic 20-foot model of an energy storage cabin was constructed using the Flacs finite element simulation software.Comparative studies were conducted to evaluate the pressure relief efficiency and the influence on neighboring battery packs in case of internal explosions,considering different sizes and installation positions of the PRV.Here,a newly developed electric-controlled PRV integrated with battery fault detection is introduced,capable of starting within 50 ms of the battery safety valve opening.Furthermore,the PRV was integrated with the battery management system and changed the battery charging and discharging strategy after the PRV was opened.Experimental tests confirmed the efficacy of this method in preventing explosions.This paper addresses the safety concerns associated with LCBPs and proposes an effective solution for explosion relief.展开更多
The objective of this numerical work is to evaluate the first law and second law performances of a hybrid nanofluid flowing through a liquidcooled microchannel heatsink.The waterbased hybrid nanofluid includes the Fe_...The objective of this numerical work is to evaluate the first law and second law performances of a hybrid nanofluid flowing through a liquidcooled microchannel heatsink.The waterbased hybrid nanofluid includes the Fe_(3)O_(4)and carbon nanotubes(CNTs)nanoparticles.The heatsink includes a microchannel configuration for the flow field to gain heat from a processor placed on the bottom of the heatsink.The effects of Fe_(3)O_(4)concentration(φFe_(3)O_(4))>CNT concentration(φCNT)and Reynolds number(Re)on the convective heat transfer coefficient,CPU surface temperature,thermal resistance,pumping power,as well as the rate of entropy generation due to the heat transfer and fluid friction is examined.The results indicated higher values of convective heat transfer coefficient,pumping power,and frictional entropy generation rate for higher values of Re,Fe_(3)O_(4)andφCNT.By increasing Re,Fe_(3)O_(4)and uCNT,the CPU surface temperature and the thermal resistance decrease,and the temperature distribution at the CPU surface became more uniform.To achieve the maximum performance of the studied heatsink,applying the hybrid nanofluid with low Fe_(3)O_(4)andφCNT was suggested,while the minimum entropy generation was achieved with the application of nanofluid with highφFe_(3)O_(4)andφCNT.展开更多
基金supported by the National Key R&D Program of China(2021YFB3803203)。
文摘As the promising cooling method for the next generation of data centers,the internal heat transport mechanism and enhancement mechanism of single-phase immersion liquid-cooled(SPILC)systems are not yet well understood.To address this,a steady-state three-dimensional numerical model is constructed herein to analyze flow and thermal transport capacities in servers using SPILC and traditional air-cooling methods.Moreover,this paper emphasizes the influence of component positioning,and underscores the benefits of optimizing coolant flow distribution using baffles.The results indicate that the SPILC system outperforms the traditional air-cooling approach at the same inlet Reynolds number(Re).When Re=10000,the SPILC method reduces the maximum temperature by up to 70.13%,increases the average convective heat transfer coefficient by287.5%,and provides better overall thermal uniformity in data center servers.Moreover,placing devices downstream of high-power components creates"thermal barriers"and degrades thermal transport for upstream devices due to increased flow resistance.Excessive spacing between high-power devices can lead to the formation of bypass channels,further deteriorating heat transfer.Additionally,the addition of baffles in the inlet section of SPILC systems effectively enhances heat dissipation performance.To maximize the heat dissipation capacity,minimizing bypass channels and optimizing the flow distribution of coolants are crucial.
基金sponsored by the Science and Technology Program of State Grid Corporation of China(4000-202355090A-1-1ZN)。
文摘The liquid-cooled battery energy sto rage system(LCBESS) has gained significant attention due to its superior thermal management capacity.However,liquid-cooled battery pack(LCBP) usually has a high sealing level above IP65,which can trap flammable and explosive gases from battery thermal runaway and cause explosions.This poses serious safety risks and challenges for LCBESS.In this study,we tested overcharged battery inside a commercial LCBP and found that the conventionally mechanical pressure relief valve(PRV) on the LCBP had a delayed response and low-pressure relief efficiency.A realistic 20-foot model of an energy storage cabin was constructed using the Flacs finite element simulation software.Comparative studies were conducted to evaluate the pressure relief efficiency and the influence on neighboring battery packs in case of internal explosions,considering different sizes and installation positions of the PRV.Here,a newly developed electric-controlled PRV integrated with battery fault detection is introduced,capable of starting within 50 ms of the battery safety valve opening.Furthermore,the PRV was integrated with the battery management system and changed the battery charging and discharging strategy after the PRV was opened.Experimental tests confirmed the efficacy of this method in preventing explosions.This paper addresses the safety concerns associated with LCBPs and proposes an effective solution for explosion relief.
文摘The objective of this numerical work is to evaluate the first law and second law performances of a hybrid nanofluid flowing through a liquidcooled microchannel heatsink.The waterbased hybrid nanofluid includes the Fe_(3)O_(4)and carbon nanotubes(CNTs)nanoparticles.The heatsink includes a microchannel configuration for the flow field to gain heat from a processor placed on the bottom of the heatsink.The effects of Fe_(3)O_(4)concentration(φFe_(3)O_(4))>CNT concentration(φCNT)and Reynolds number(Re)on the convective heat transfer coefficient,CPU surface temperature,thermal resistance,pumping power,as well as the rate of entropy generation due to the heat transfer and fluid friction is examined.The results indicated higher values of convective heat transfer coefficient,pumping power,and frictional entropy generation rate for higher values of Re,Fe_(3)O_(4)andφCNT.By increasing Re,Fe_(3)O_(4)and uCNT,the CPU surface temperature and the thermal resistance decrease,and the temperature distribution at the CPU surface became more uniform.To achieve the maximum performance of the studied heatsink,applying the hybrid nanofluid with low Fe_(3)O_(4)andφCNT was suggested,while the minimum entropy generation was achieved with the application of nanofluid with highφFe_(3)O_(4)andφCNT.
