Performance enhancement for exhaust thermoelectric power generation system by using porous pin fins based on a fully automatic optimization method

Abstract

An intelligent optimization method combining Non-dominated Sorting Genetic Algorithm-II (NSGA-II) algorithm and Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) decision is implemented to design the optimal arrangement of porous pin fins in the flow channel of the exhaust thermoelectric power generation (ETEG) system. This method realizes the optimal arrangement of the porous pin fins while considering the two contradictory performance indicators at the optimization level: system output power (P) and pressure drop (Pd). In this work, the design of porous and solid pin fins is first compared. Secondly, four typical pin fins arrangement models are established with preliminary analysis. Finally, the NSGA-II-TOPSIS intelligent optimization method is implemented, which takes P and Pd as objective function, the position, number and relative distance of the porous pin fins as optimization variables simultaneously. Through iterative optimization, the optimal arrangement scheme achieves a proper balance between P and Pd. The main conclusions include: The design of the porous pin fins can increase 22.89% for P of the ETEG system while reduces 82.98% for Pd. The distribution of dense downstream of porous pin fins can best improve the ETEG system performance. After optimization, higher P and lower Pd of the ETEG system are obtained with fewer pin fins. A new index is proposed to evaluate optimal solutions, the optimal design with 2 porous pin fins reaches the highest value: 5.86 W Pa−1, which means that each pin fin is fully used.