The Influence Of The Core Flow Heat Transfer Enhancement On The Performance Of Automobile Exhaust Thermoelectric Generator

With the development of the automobile industry,the energy consumption of vehicles is increasing.The energy saving and emission reduction in the automotive industry has also become a major research topic.The engine fuel economy is an important index of vehicle energy efficiency.Considering thatthe technology of engine is relatively mature,it is a difficult way to improve the fuel economy from improving the performance of automobile engine.But considering from the characteristics of engine exhaust excess heat and high temperature.However,from the point of view of the characteristics of engine exhaust more heat and much higher temperature,it is of great significance to the automobile energy saving and emission reduction if the waste heat from the exhaust of automobile could be recovered by using semiconductor thermoelectric generation technology and turned into electric energy for the use of vehicle electric appliances or become a part of the power of the hybrid electric vehicle.Based on the history of the development of semiconductor thermoelectric power generation technology and the review and summary of its research and application in the field of waste heat recovery and utilization,this paper found that as a convenient medium and low temperature energy generation technology,the thermoelectric power generation technology has made positive progress in the field of material development and application,but the low efficiency of thermoelectric conversion is still one of the key factors that restrict its wide application.In order to improve the thermal power conversion efficiency of the thermoelectric generator,in addition to the research on the development of new high performance semiconductor materials,it is an important research direction to strengthen the heat transfer between the cold and heat source fluid and the cold and hot sides of thermoelectric generator,and to reduce the heat transfer temperature difference between the fluid and the cold and hot sides of the generator.Therefore,the basic characteristic of the waste heat of automobile exhaust of thermoelectric generator is studied by theoretical analysis and experimental verification in this paper.And on the basis of this,the influence of heat transfer enhancement on the performance of thermoelectric generator is discussed in this paper,which provides reference and guidance for the application of thermoelectric generator in the field of automobile exhaust waste heat recovery and utilization.The main research contents include:1.According to the vehicle exhaust flow status and the temperature distribution rule,the structure characteristics of vehicle exhaust system is analyzed.An experimental test system for generating thermoelectric power by exhaust heat from automobile is designed and established,and the basic research on the influence of thermal parameters of heat source gas on the performance of thermoelectric generator is carried out.The reliability and applicability of the experimental device are verified,and the characteristics of heat transfer and conversion in the process are revealed.2.A method of enhancing convection heat transfer by filling porous medium(foam metal)in gas core flow area in exhaust tube is proposed.While increasing the heat exchange between vehicle exhaust and thermoelectric generator,reducing the flow resistance produced by porous materials.Through the theoretical study and experimental analysis of the core flow strengthening heat transfer with the porous media,the mechanism of heat transfer enhancement and the influence of the characteristic parameters of porous medium on the heat transfer are revealed.3.The influence of heat transfer enhancement of core flow in porous media on vehicle exhaust thermoelectric generation system is studied.The influence of different hot side conditions on the output power of generator is analyzed.The thermoelectric modules with different thermoelectric conversion characteristics are applied to improve the performance of the generator by matching and optimizing the thermoelectric modules and the characteristics of system.