Design of Annular Thermoelectric Generators System to Recover Waste Heat From Aircraft Jet Engine

Abstract

Thermoelectric (TE) materials were investigated in several applications due to their capability to convert waste heat into electrical power. The possibility of implementing thermoelectric generators (TEGs) onto exhaust pipe of turbojet engine to recover waste heat energy is introduced in this study using 3D finite element method. The annular TE configuration can be mounted on the exhaust pipe utilizing the temperature difference between hot gas flow and cool air bypass flow. Geometrical parameters of annular TEGs structure such, TE leg angle, and gap distance angle are also optimized to quantify the total amount of TE modules on the outer surface area of the exhaust pipe. Due to higher values of thermomechanical properties, silicon germanium which also performs better at higher temperature range with higher values of figure of merit (ZT) is selected as TE materials. However, due to high temperature gradient, the cascade annular thermoelectric systems are also included in this study by inserting skutterudite as another TE material at lower stage which is suitable at intermediate temperature range. The comparison of using annular single stage (silicon germanium) and two stages (silicon germanium & skutterudite) TE systems is investigated.