Research on thermal performance and optimization design of phase change pin fin heat sink based on Lattice Boltzmann method

This paper reports a numerical research of the phase change materials (PCMs) based pin fin heat sinks for thermal management of battery and electronic device. The 58 semi-refined paraffin and several paraffin/CNTs composites (CNT mass fraction of 5 %, 8 %, 10 %) were adopted as PCMs filled in the heat sink. Lattice Boltzmann method (LBM) was used to numerically study the influence of fin geometry (square fin, circular fin, cross fin), fin number (one to five), fin arrangement (array arrangement, cross arrangement) and PCMs on the working performance (charging time and heat dissipation power) of the heat sinks. The LBM code was solved in Visual Basic. The results report that the four/five square fins (arrangement A) heat sink with 10 % CNT compound paraffin has the shortest charging time and the heat sink with four square fins (arrangement A) and 8 % CNT compound paraffin has the largest heat dissipation power. It is worth noted that compared with square fin heat sinks, the cross fin heat sinks still present 83 % of the heat dissipation power with only 36 % of the fin volume. Besides, aiming at acquiring the largest heat dissipation power, a back propagation neural network-genetic algorithm was developed to optimize the structure of the pin fin heat sink. The corresponding fin number, fin side length and fin distance for the optimized square fin heat sink (arrangement A) are 4, 2.13 mm and 5.88 mm, respectively.