硅基内肋阵列微通道内的流动和换热特性

Flow and Heat Transfer Characteristics in Silicon-Based Pin-Fin Microchannels

制作了四种带有圆柱形内肋阵列的硅基微通道,以去离子水为工质对其内部流动和换热特性进行了实验研究,并与平直微通道进行了对比,分析了内肋阵列微通道中流动阻力提升和强化换热的机理。研究表明;内肋阵列带来较大阻力的同时也极大地改善了换热;流体流经内肋阵列微通道时,其阻力在低Re数下主要来自壁面效应产生的摩擦阻力,高Re数下则受绕肋产生尾涡的影响较大;不同内肋布置方式对流体流动和换热影响显著,叉排布置比顺排布置的内肋阵列微通道具有更大的摩擦因子和换热系数,且增大垂直于流动方向内肋密度更有利于增强换热;内肋排列最为紧密的微通道#2综合换热性能最好,相同泵功下,其换热热阻相对于平直微通道降低了53.4%。

Four kinds of silicon-based microchannels with different cylindrical pin-fin arrangements were designed and fabricated. Using water as the working fluid, the flow and heat transfer character- istics in different pin-fin microchannels were investigated experimentally. And the experimental data were also compared with those of the plain microchannel to analyze the mechanism of flow resistance increasement and heat transfer enhancement. The results showed that pin-fin arrays enhanced heat transfer coefficients obviously while increased flow resistances simultaneously. At lower Reynolds number, the resistance was mainly caused by the wall friction effect, while at relatively higher Reynolds number, the contribution of trailing vortex to the flow resistance became larger. Under the same conditions, larger friction factors and heat transfer coefficients were obtained in the staggered pin-fin microchannels than in the in-line pin-fin microchannels. Increasing the pin-fin arrangement density vertical to the flow direction, the heat transfer enhancement is more obvious. The staggered pin-fin microchannel with the most dense pin-fin arrangement has a higher overall heat transfer performance, with the thermal resistance reduction by an average of 53.4% compared with the plain microchannel under the same pump power.