粗糙度对微细通道内流动特性影响的实验研究  

Experimental study of flow characteristics in microchannels with different surface roughness

作　　者：张春平[1] 唐大伟[1] 曲伟[1] 郑兴华[1] 

机构地区：[1]中国科学院 工程热物理研究所,北京100080

出　　处：《上海理工大学学报》2008年第1期55-58,共4页Journal of University of Shanghai For Science and Technology

基　　金：中国科学院知识创新工程重要方向性项目(KGCX1-SW-12)

摘　　要：对几何特性相似而粗糙度不同的3种不锈钢矩形微槽内水、乙醇和正己烷的流动特性进行了实验研究.研究发现,在层流区随着雷诺数(Re)的增大,摩擦阻力常数fRe也缓慢增大,与传统理论的fRe是常数不同,且相对粗糙度越大,fRe值也越大.对于相对粗糙度较小(k/D_h<3%)的两种微槽转捩Re均在1 685～1 760之间,与传统理论相比,转捩并未提前.但相对粗糙度为3.15%的微槽的转捩Re数为1 500,与传统理论相比,转捩已提前.层流区摩擦阻力系数均高于传统理论预测值,相对粗糙度较小(k/D_h<3%)的两个微槽的摩擦阻力系数在Re<1 600的层流区域基本相同。但在Re=200～2 800的测量范围内,相对粗糙度大于3%的微槽的摩擦阻力系数均比相对粗糙度小于3%的微槽的要大.过渡区域的摩擦阻力系数均比传统预测值高30%～40%.工质极性对摩擦阻力的影响很小.An experimental investigation has been performed on flow characteristics and pressure drop of water, alcohol and hexane in 3 different roughness rectangle stainless steel microchannels. It is found that the hagen-poiseuille number is higher than those predicted by the classical theory and the hagenpoiseuiUe number is unconstant but slowly increases with the Reynolds number and increases with the surface roughness in laminar area. For the small relative roughness（ k/Dh〈 3 % ）, the critical Re number is between 1 685 and 1 760 which shows that the laminar-turbulent transition in microchannels will not appear earlier than that the classical theory expects. But for the large relative roughness（ k/Dh = 3.15 % ）, the critical Re number is about 1 500 which shows that laminar-turbulent transition in microchannels does occur in advance. The experimental results also show that for the small relative roughness（ k/Dh〈3% ） and for Reynolds number smaller than 1 600, the friction fractor maintains almost the same value, but for the large relative roughness（ k/19h = 3.15% ）, and for Reynolds number between 200-2 800, the friction factor becomes higher. The friction factor is about 30 % -40 % higher than the traditional predicted value. The liquid polarity has little effect on friction factor.

关 键 词：粗糙度 微通道 摩擦阻力系数 

分 类 号：TK124[动力工程及工程热物理—工程热物理]