Analysis of transient energy conversion performance improvement of thermoelectric generator with penetrating crack under pulsed heat source

Abstract

To simulate the performance of a thermoelectric generator (TEG) in practical applications more accurately and comprehensively analyse the influence of transient heat source and crack on such devices, it is necessary to examine the transient performance of TEGs with cracks under periodic pulsed heat source. In this study, a three-dimensional nonlinear dynamic finite element model with thermal, electrical, and mechanical coupling was established, and the laws describing the macroscopic electrical energy output and thermal stress distribution were derived. The position of the maximum thermal stress changed as the crack size varied. When the crack field axis was increased from 0.2 mm to 1.8 mm, the total output energy increased by 14.4 %, whereas the thermal stress increased to 447 MPa. The total energy growth rate under pulsed heat source conditions reached 52.3 % (from 62.71 J to 95.52 J) compared with that of the steady-state heat source. However, the maximum thermal stress increased by 173.6 % (from 91 MPa to 249 MPa). The results show that the crack and pulsed heat source can effectively improve the electrical output performance of TEGs; however, their mechanical properties deteriorated. This study is useful in terms of predicting the performance of TEGs in practical applications more accurately.