Optimization And Analysis Of Automobile Exhaust Waste Heat Thermoelectric Generation Device

With the rapid development of automobile industry,the development of the global economy has been quickly boosted,meanwhile,a large number of petroleum resources is almost exhausted,which produces much pollutants as Green-House Gas,NOX and Particulate Matter(PM).Gasoline is the main power energy for automobile,in actual situation oil only can be used by 30%,40% of which is discharged as vehicle exhaust gases and taken off by cooling system.This paper involves a cylindrical automobile exhaust thermoelectric generator(TEG),which uses thermoelectric generation technology to recover waste heat from automobile exhaust.Heat exchanger is the main part of TEG,the value and uniformity of surface temperature has a great influence on the output of TEG.Aiming at waste heat recycling,this paper mainly does some research about the heat exchanger and the overall structure of TEG.According to the difference of heat exchanger in built-in fin structure,this paper puts forward two kinds of heat exchangers,that is,twisted finned heat exchanger and helix finned heat exchanger.It mainly studies the effect of twistedly finned pitch angle,helix fin pitch,fin thickness and fin height on the thermal performance of heat exchanger.The heat exchanger performance is reflected by the indexes such as temperature uniformity coefficient,back pressure of heat exchanger and wall average temperature.The heat exchanger models with different fin structure are established in CATIA software and imported into ANSYS Workbench simulation platform to establish the conjugate heat transfer calculation model of heat exchanger.The specified boundary conditions of engine working conditions for the simulation models are gotten by GT-Suite.Using CFD code CFX carries out the numerical simulation solution.Based on the simulation results about the effect of fin structure on the performance of heat exchanger,the helix finned heat exchanger has been optimized.The spiral finned heat exchanger with variable pitch is presented and made the same process of thermal analysis with the old heat exchanger.Finally,TEG model simulation having the spiral finned heat exchanger with variable pitch is carried out,and how much the device can generate electricity is estimated.The research method in this paper provides a method to guide the design and improvement of the automobile exhaust thermoelectric generator.