轴向导热对微通道内传热特性的影响  

Effect of axial heat conduction on heat transfer in micro-channels

作　　者：甘云华[1] 杨泽亮[1] 

机构地区：[1]华南理工大学电力学院,广东广州510641

出　　处：《化工学报》2008年第10期2436-2441,共6页CIESC Journal

基　　金：国家自然科学基金项目(50806022)~~

摘　　要：以去离子水为工质,在当量直径为155.3μm的三角形硅基微通道中进行了传热特性的实验研究;采用轴向导热与总加热量的比值和轴向导热准则数来分析轴向导热对微通道内传热特性的影响;基于实验结果,对入口段长度进行了计算。根据红外热像仪的测量结果,局部壁面温度沿流动方向上呈非线性规律分布,并计算得出局部Nusselt数沿流动方向上的分布规律。轴向导热与总加热量的比值的变化范围为0.106～0.275,表明轴向导热对微通道内传热特性的影响显著,特别是在Reynolds数较小的情况下。对轴向导热准则数进行了新的修正,在热流密度与入口温度相近的情况下,轴向导热准则数随Reynolds数的增加而减小。Experiments were conducted to study the heat transfer characteristics of water flowing through triangular silicon micro-channels with a hydraulic diameter of 155.3μm. The ratio of axial heat conduction to the whole heating and the axial heat conduction number were used to evaluate the effect of axial heat conduction on heat transfer in micro-channels. The thermal entry lengths for all cases were calculated based on experimental results. The measurements by IR camera showed that the local wall temperature did not change linearly along the channel, which was mainly caused by the axial heat conduction in the wall. And the local Nusselt number distributions along the flow direction were calculated based on experimental results. The ratio of the axial heat conduction to the whole heating varied from 0. 106 to 0. 275, indicating that the axial heat conduction might play an important role in heat transfer in micro-channels, especially when Reynolds number was low. The axial heat conduction number was modified in the present study. The experimental study revealed that the axial heat conduction number decreased with increasing Reynolds number when keeping heat input and inlet water temperature nearly constant.

关 键 词：微尺度传热 微通道 轴向导热 

分 类 号：TK124[动力工程及工程热物理—工程热物理]