高碳醇/膨胀石墨复合相变热沉多目标优化

A novel composite Phase Change Material (PCM) based heat sink is proposed to cool chips under high ambient temperature. Physical and numerical model is proposed for the heat sink. High alcohol/expanded graphite composite material is chosen as PCM in the heat sink. Numerical model is obtained with the help of FLUENT software for three-dimensional simulation. The effect of heated area on the chip's operation time under same thermal output is investigated. Parameter analysis is performed on the geometric dimensions of the heat sink. Artificial neural network is trained with numerical results to predict the operation time of a given heat sink / chip configuration. NGSA-Ⅱ multi-objective optimization algorithm is employed to optimize the geometric shape of heat sink based on chip size and power output. The main objective is to stretch operation time while reducing the total weight of the heat sink. A series of non-dominate solution is obtained so that optimal geometric design can be chosen based on operation time needs. The optimization process is carried out to obtain the optimal heat sink design to cool a chip, whose side length is 35. 4 mm with constant power output of 15 W. The ambient temperature is 80℃ while the chip needs to be kept under 90℃ for a sustained operation time of at least 180 s. After optimization, the weight of heat sink is reduced by 13. 0%. The temperature and the liquid fraction distribution are more uniform.