Research Of Heat Transfer For Contact Interface Of Thermoelectric Modulc Based On Thermoelectric Generation System

In the automotive exhaust Thermoelectric Generator(TEG),the heat of the exhaust is transferred from the heat exchanger to the thermoelectric device,part of it converted into electricity,and part of it is transferred from thermoelectric device to the radiator.This heat is eventually taken away by the coolant in the radiator.During the whole energy transfer,the heat passes through several interfaces,including the interface between the hot side of the thermoelectric device and the surface of the heat exchanger,the interface between the cold side of the thermoelectric device and the surface of the radiator,and the contact interfaces inside the thermoelectric device.Due to the surface micro-roughness,not all areas are in contact with each other between the two faces.The contact effect of contact surface will affect the heat collection at the hot side of the thermoelectric device and the heat dissipation at cold side.That will affect the power generation efficiency of the TEG.Based on the basic principle of TEG and combined with domestic and foreign research status,the heat transfer characteristics of thermoelectric devices contact interface in TEG is studied in this paper.According to the theory of heat transfer,the geometrical model of surface topography and the theory of contact mechanics,the theoretical formula of thermal contact resistance is deduced,and the thermal resistance analysis model of TEG is established.Relying on laboratory thermoelectric device test platform,TEG heat transfer and power generation research bench is built.The thermal resistance distribution and output power of the TEG are measured by the experimental bench.The relationship between surface roughness,contact pressure,material properties and contact resistance,power generation is investigated.According to the theoretical model of contact resistance and the principle of thermoelectric power generation,a thermoelectric coupling numerical model of TEG is established.Through this model,the temperature distribution and output power of the TEG are calculated in different surface profile root mean square deviation,average slope of surface profile,thermal conductivity,microhardness and the contact pressure of the contact interface.And the influence of the surface morphological parameters of the contact surface,the physical properties of the material and the contact pressure on the contact resistance and the power generation performance is analyzed in depth.Finally,the numerical model of the automotive exhaust TEG system including the heat exchanger,the cooling water tank and the thermoelectric device is established.After constructing the evaluation index of system performance,the relationship between the thermal resistance and thermal efficiency,power generation efficiency of the TEG is studied.By comparing the effects of the thermal contact resistance and the heat transfer performance of heat exchangers on the performance of TEG,the relationship between the thermal contact resistance and the power loss of the heat exchanger and the system power generation under different working conditions is analyzed.And the research result can guide the design of thermoelectric generators.In this paper,the influence of the surface morphology,material properties of the heat exchanger and the contact pressure on the temperature distribution of the TEG is studied.The heat transfer characteristic of the contact interface of the thermoelectric device is analyzed.The relationship between these factors and the thermal contact resistance and power generation is obtained.The influence of thermal contact resistance on performance of automotive exhaust TEG is studied.The research results provide a theoretical basis for the design and development of TEG.