Aiming at reducing the difficulty of cooling the interior of high-density motors,this study proposed the placement of a water cold plate cooling structure between the axial laminations of the motor stator.The effect o...Aiming at reducing the difficulty of cooling the interior of high-density motors,this study proposed the placement of a water cold plate cooling structure between the axial laminations of the motor stator.The effect of the cooling water flow,thickness of the plate,and motor loss density on the cooling effect of the water cold plate were studied.To compare the cooling performance of water cold plate and outer spiral water jacket cooling structures,a high-speed permanent magnet motor with a high loss density was used to establish two motor models with the two cooling structures.Consequently,the cooling effects of the two models were analyzed using the finite element method under the same loss density,coolant flow,and main dimensions.The results were as follows.(1)The maximum and average temperatures of the water cold plate structure were reduced by 25.5%and 30.5%,respectively,compared to that of the outer spiral water jacket motor;(2)Compared with the outer spiral water jacket structure,the water cold plate structure can reduce the overall mass and volume of the motor.Considering a 100 kW high-speed permanent magnet motor as an example,a water cold plate cooling system was designed,and the temperature distribution is analyzed,with the result indicating that the cooling structure satisfied the cooling requirements of the high loss density motor.展开更多
In order to reduce the power consumption and meet the cooling demand of every heat source component, three kinds of multi-heat source cooling system schemes were designed base on the characteristic of power split hybr...In order to reduce the power consumption and meet the cooling demand of every heat source component, three kinds of multi-heat source cooling system schemes were designed base on the characteristic of power split hybrid electric vehicle （HEV）. Using the numerical simulation meth- od, the power system heat transfer model was built. By comparing the performance of three differ- ent schemes through the Simulink simulation, the best cooling system scheme was found. Base on characteristics of these cooling system structures, the reasonableness of the simulation results were analyzed and verified. The results showed that the cooling system designation based on the numerical simulation could describe the cooling system performance accurately. This method could simplify the design process, improve design efficiency and provide a new way for designing a multi-heat source vehicle cooling system.展开更多
An experimental investigation of passive cooling buildings has been carried out for a typical summer days extended from July to December of Baghdad in Iraq. Six independent chambers were designed and constructed for d...An experimental investigation of passive cooling buildings has been carried out for a typical summer days extended from July to December of Baghdad in Iraq. Six independent chambers were designed and constructed for different roof constructions. Night ventilation has been applied to study the possibility of reducing air temperature in buildings by testing different air changes per hour extended from 5 to 30. Measurements outside chambers including air temperature; relative humidity and solar radiation were achieved, while surface temperature and air temperature inside the chambers were recorded. The results show that the air temperature can be decreased with a range from 3 ℃ to 6 ℃ when using 50 mm polystyrene. This decrease can further be lowered by 2 ℃ to 4 ℃ if night ventilation of change per hours in buildings is allowed. The reduction in air temperature can be reduced to 5 ℃ by combination of external night ventilation and white paint.展开更多
This paper presents a thermal management framework for 120 kV hybrid commutated converter(HCC)valves,addressing critical cooling challenges in multi-hundred-MW power conversion systems.Power loss calculations under ra...This paper presents a thermal management framework for 120 kV hybrid commutated converter(HCC)valves,addressing critical cooling challenges in multi-hundred-MW power conversion systems.Power loss calculations under rated(1.0 p.u.)and overload(1.2 p.u.)conditions demonstrate that HCC valves achieve comparable loss levels to line commutated converter counterparts while enabling active turn-off control.Comparative analysis of radiator configurations identifies 2-parallel branch connections as optimal.Integrated thermal-fluid models combining 3D finite element analysis and computational fluid dynamics reveal significant temperature gradients and flow maldistribution in baseline designs.On this basis,this paper modifies the flow from equal flow resistance allocation to heat-based allocation and it reduces maximum integrated gate-commutated thyristor temperature rise by 7.3%at 1.2 p.u.with minimal pressure drop variation.Experimental validation confirms the proposed cooling strategy enhances valve safety margins through improved heat dissipation balance,providing a validated theoretical foundation for high-power converter thermal design.展开更多
Nuclear reactor safety(NRS)and the branch accident analysis(AA)constitute proven technologies:these are based on,among the other things,long lasting research and operational experience in the area of water cooled nucl...Nuclear reactor safety(NRS)and the branch accident analysis(AA)constitute proven technologies:these are based on,among the other things,long lasting research and operational experience in the area of water cooled nuclear reactors(WCNR).Large break loss of coolant accident(LBLOCA)has been,so far,the orienting scenario within AA and a basis for the design of reactors.An incomplete vision for those technologies during the last few years is as follows:Progress in fundamentals was stagnant,namely in those countries where the WCNR were designed.Weaknesses became evident,noticeably in relation to nuclear fuel under high burn-up.Best estimate plus uncertainty(BEPU)techniques were perfected and available for application.Electronic and informatics systems were in extensive use and their impact in case of accident becomes more and more un-checked(however,quite irrelevant in case of LBLOCA).The time delay between technological discoveries and applications was becoming longer.The present paper deals with the LBLOCA that is inserted into the above context.Key conclusion is that regulations need suitable modification,rather than lowering the importance and the role of LBLOCA.Moreover,strengths of emergency core cooling system(ECCS)and containment need a tight link.展开更多
基金supported by the National Natural Science Foundation of China(51920105011)Natural Science Foundation of Liaoning Province(2021-YQ-09)Liaoning Bai Qian Wan Talents Program,China.
文摘Aiming at reducing the difficulty of cooling the interior of high-density motors,this study proposed the placement of a water cold plate cooling structure between the axial laminations of the motor stator.The effect of the cooling water flow,thickness of the plate,and motor loss density on the cooling effect of the water cold plate were studied.To compare the cooling performance of water cold plate and outer spiral water jacket cooling structures,a high-speed permanent magnet motor with a high loss density was used to establish two motor models with the two cooling structures.Consequently,the cooling effects of the two models were analyzed using the finite element method under the same loss density,coolant flow,and main dimensions.The results were as follows.(1)The maximum and average temperatures of the water cold plate structure were reduced by 25.5%and 30.5%,respectively,compared to that of the outer spiral water jacket motor;(2)Compared with the outer spiral water jacket structure,the water cold plate structure can reduce the overall mass and volume of the motor.Considering a 100 kW high-speed permanent magnet motor as an example,a water cold plate cooling system was designed,and the temperature distribution is analyzed,with the result indicating that the cooling structure satisfied the cooling requirements of the high loss density motor.
基金Supported by the Ministerial Level Advanced Research Foundation(40402070101)
文摘In order to reduce the power consumption and meet the cooling demand of every heat source component, three kinds of multi-heat source cooling system schemes were designed base on the characteristic of power split hybrid electric vehicle （HEV）. Using the numerical simulation meth- od, the power system heat transfer model was built. By comparing the performance of three differ- ent schemes through the Simulink simulation, the best cooling system scheme was found. Base on characteristics of these cooling system structures, the reasonableness of the simulation results were analyzed and verified. The results showed that the cooling system designation based on the numerical simulation could describe the cooling system performance accurately. This method could simplify the design process, improve design efficiency and provide a new way for designing a multi-heat source vehicle cooling system.
文摘An experimental investigation of passive cooling buildings has been carried out for a typical summer days extended from July to December of Baghdad in Iraq. Six independent chambers were designed and constructed for different roof constructions. Night ventilation has been applied to study the possibility of reducing air temperature in buildings by testing different air changes per hour extended from 5 to 30. Measurements outside chambers including air temperature; relative humidity and solar radiation were achieved, while surface temperature and air temperature inside the chambers were recorded. The results show that the air temperature can be decreased with a range from 3 ℃ to 6 ℃ when using 50 mm polystyrene. This decrease can further be lowered by 2 ℃ to 4 ℃ if night ventilation of change per hours in buildings is allowed. The reduction in air temperature can be reduced to 5 ℃ by combination of external night ventilation and white paint.
基金National Key Research and Development Program,Grant/Award Number:2023YFB2405900。
文摘This paper presents a thermal management framework for 120 kV hybrid commutated converter(HCC)valves,addressing critical cooling challenges in multi-hundred-MW power conversion systems.Power loss calculations under rated(1.0 p.u.)and overload(1.2 p.u.)conditions demonstrate that HCC valves achieve comparable loss levels to line commutated converter counterparts while enabling active turn-off control.Comparative analysis of radiator configurations identifies 2-parallel branch connections as optimal.Integrated thermal-fluid models combining 3D finite element analysis and computational fluid dynamics reveal significant temperature gradients and flow maldistribution in baseline designs.On this basis,this paper modifies the flow from equal flow resistance allocation to heat-based allocation and it reduces maximum integrated gate-commutated thyristor temperature rise by 7.3%at 1.2 p.u.with minimal pressure drop variation.Experimental validation confirms the proposed cooling strategy enhances valve safety margins through improved heat dissipation balance,providing a validated theoretical foundation for high-power converter thermal design.
基金the Institutional Funds ofUniversity of Pisa,Italy。
文摘Nuclear reactor safety(NRS)and the branch accident analysis(AA)constitute proven technologies:these are based on,among the other things,long lasting research and operational experience in the area of water cooled nuclear reactors(WCNR).Large break loss of coolant accident(LBLOCA)has been,so far,the orienting scenario within AA and a basis for the design of reactors.An incomplete vision for those technologies during the last few years is as follows:Progress in fundamentals was stagnant,namely in those countries where the WCNR were designed.Weaknesses became evident,noticeably in relation to nuclear fuel under high burn-up.Best estimate plus uncertainty(BEPU)techniques were perfected and available for application.Electronic and informatics systems were in extensive use and their impact in case of accident becomes more and more un-checked(however,quite irrelevant in case of LBLOCA).The time delay between technological discoveries and applications was becoming longer.The present paper deals with the LBLOCA that is inserted into the above context.Key conclusion is that regulations need suitable modification,rather than lowering the importance and the role of LBLOCA.Moreover,strengths of emergency core cooling system(ECCS)and containment need a tight link.
