Numerical investigation on thermal and fluid dynamic behaviors of a thermoelectric generator in an exhaust automotive line with aluminium foam

In the present work a two-dimensional steady state convective heat transfer problem in a channel aluminum foam partially filled with an external thermos-electrical generator (TEG) component is numerically solved. The channel is characterized by a length equal to 272 mm and by a height of 60mm; instead, the TEG has a length equal to 65 mm and a thickness of 8.5 mm. The metal foam is modelled assuming the local thermal equilibrium (LTE) hypothesis. The TEG is analyzed as a solid with an internal energy generation. Thermophysical properties of the exhaust gas are assumed equal to the ones of the air. The governing equations are considered with temperature independent thermophysical properties. The governing equations for gas, porous media and TEG are solved by finite volume method using the Ansys-Fluent code. The foam is characterized by a porosity of 0.92 and number of pores per inch equal to 5, 20, 40. Results are carried out for several mass flow rates of gas and different thicknesses of metal foam. Results are given in terms of temperature distributions, pressure drop, thermoelectric efficiency and power density for TEG for different exhaust gas flow rates and aluminum foam thicknesses.