基于康托尔分形微通道流动与传热的模拟

高密度、 小体积和高集成的电子元器件散热困难, 易造成过早失效, 采用微通道换热器可以实现小体积内高热流的散热, 但流动阻力很大. 为了保证传热效果, 降低流动阻力, 本文提出了一种新型的微通道结构并对其流动与传热特性进行了数值模拟. 首先研究了微通道形状和结构, 模拟结果表明: 进出口截面宽高比为0.8 的矩形微通道的换热效果最好; 并在此基础上提出一种康托尔分型凹槽结构, 研究了有无康托尔分形以及不同分形级数对流动与传热性能的影响, 综合对比发现: 第二级康托尔分形模型 N2 既能保证热阻显著降低, 又能相比阵列结构降低压降, 具有明显的换热优势; 最后对这种康托尔分形结构的凹槽形状, 尺寸及不同方向上的分形进行研究, 结果表明梯形凹槽的下上表面长度比b/a 为0.6 、 流动方向分形比fx 为1 .25 和通道高度方向分形比fy 为1 .5 时换热流动性能最佳.

Simulation of Flow and Heat Transfer Based on Cantor Fractal Microchannel

The heat dissipation of high-density, small volume and highly integrated electronic components is difficult and easy to cause premature failure. The use of micro-channel heat exchanger can achieve heat dissipation of high heat flow in small volume, but the flow resistance is very large. In order to ensure the heat transfer effect and reduce the flow resistance, a new microchannel structure is proposed and its flow and heat transfer characteristics are simulated numerically. Firstly, the shape and structure of the microchannel are studied. The simulation results show that the rectangular microchannel with inlet and outlet section aspect ratio of 0.8 has the best heat transfer effect. On this basis, a Cantor fractal groove structure is proposed, and the influence of cantor fractal and different fractal series on flow and heat transfer performance is studied. The second stage cantor fractal model N2 can not only reduce the thermal resistance significantly, but also reduce the pressure drop compared with the array structure, which has obvious advantages in heat transfer. Finally, the groove shape, dimension and fractal in different directions of the Cantor fractal structure are studied. The results show that the heat transfer performance of the trapezoidal groove is the best when the length ratio b/a is 0.6,the flow direction fractal ratio fx is 1.25 and the channel height direction fractal ratio fy is 1.5.