Al_(2)O_(3)纳米流体自激式脉动传热的热流道结构优选

Optimization of Hot Runner Structure for Self-excited Pulsating Heat Transfer of Al_(2)O_(3) Nanofluid

在对流传热过程中,如何增加边界扰动以改善传热性能,是实现强化传热的关键问题。基于自激振荡腔的脉动效应和纳米流体的高热导率,提出了一种纳米流体无源脉动强化传热机制。采用正交数值试验方法对自激振荡热流道的主要结构参数进行优化研究,利用大涡模拟湍流模型分析了热流道的结构参数对Al_(2)O_(3)纳米流体传热特性的影响规律,并获得了最优结构参数配比。结果表明:腔室长度对热流道中纳米流体的传热性能影响最大,腔室直径影响最小,并观察到无量纲参数L/d_(1)=7、D/d_(1)=11、d_(2)/d_(0)=1.1的自激振荡热流道具有最佳传热性能。

In the process of convective heat transfer, how to increase the boundary disturbance to improve the heat transfer performance is the key issue to realize the enhancement of heat transfer. Based on the pulsation effect of the self-excited oscillation chamber and the high thermal conductivity of the nanofluid, a passive pulsation enhanced heat transfer mechanism of the nanofluid is proposed in this study. The orthogonal numerical experiment method was used to optimize the main structural parameters of the self-excited oscillation hot runner. The large eddy simulation turbulence model was used to analyze the influence of the hot runner structural parameters on the heat transfer characteristics of the Al_(2)O_(3) nanofluid, and the optimal structural parameter ratio was obtained. The orthogonal numerical experiment results show that the length of the chamber has the greatest effect on the heat transfer performance of the nanofluid in the hot runner, and the diameter of the chamber has the least effect. It is also observed that the self-excited oscillating hot runner has the best heat transfer performance when dimensionless parameters L/d1=7, D/d1=11 and d2/d0=1.1.