强迫对流冷却圆柱体离散热源的构形优化研究

Study on Constructal Optimization for Cylindrical Discrete Heat Sources Cooled by Forced Convection

在强迫对流条件下,建立了导热基座上的三维圆柱体离散热源散热模型,以最高温度最小化为目标,以热源的高度比、间距比和半径比为优化设计变量,开展了构形优化研究。结果表明:等热源强度的热源阵列沿气流方向按半径由大到小、高度由低到高、间距由疏到密的布置可降低离散热源的最高温度,即多尺度非均匀分布的热源阵列,有利于防止热源烧蚀。对于一些特定高度比和间距比的热源阵列,当离散热源等半径时,而不再是热源半径沿气流方向逐渐增大或者逐渐减小时最高温度取得最小值。这说明,不是任意多尺度结构设计就可提高热源散热性能,而是不同几何尺寸间存在最佳配合即最优构形以达到最优散热性能。

A 3-D heat dissipation model of cylindrical discrete heat sources on a heat conduction base under forced convection condition is established and the constructal optimization is carried out by taking the height ratio,the spacing ratio and the radius ratio among the heat sources as the optimization variables and taking the maximum temperature minimization as the optimization objective.The results show that the maximum temperature can be decreased by the distribution of the array with heat sources from large to small in radius,from low to high in height,from sparse to dense in spacing along the direction of air flow,i.e.multi-scale and non-uniform distribution of heat sources is benefit to prevent heat source ablation.For the heat source arrays with some specific height ratios and spacing ratios,the maximum temperatures reach the minimums when the discrete heat sources are equal in radius rather than from large to small or from small to large in radius along the direction of air flow.That is,not all of multi-scale structure designs can improve the heat dissipation performance of the heat sources and there exists the optimal matching between the different geometrical dimensions,i.e.the optimal constructure,for achieving the best heat dissipation performance.