Abstract:

De-ionized water, used as working fluid, flowed through micro/mini cylinder group plates with 3.5 mm width and 40 mm length, which were made up of micro/mini cylinder group with diameter of 0.5 mm and heights of 1.0 mm, 0.75 mm, 0.5 mm and 0.25 mm, respectively.The flow rate and pressure drop between inlet and outlet of micro/mini cylinder group plates were measured and the resistance characteristics of micro/mini plates at staggered array and at in-line array could be experimentally studied.The investigation showed that the value of fRe was approximately constant in micro/mini cylinder group plates when flow was purely laminar state.The values of fRe for all test sections except test sections with 0.25 mm cylinder height would increase with the increase of Re at Re>100, as a result of eddy resistance, enhancement of stream pulse and acceleration of stream frequency.For test sections with 0.25 mm cylinder height, the values of fRe increased quickly and oscillatingly when Re was larger than 150 due to the influence of the micro-size effect and the roughness effect on the cylinder surface and bottom of micro/mini cylinder group plates.The friction factor at staggered array was much larger than that at in-line array for micro/mini cylinder group plates, and the higher the cylinder height, the lower the friction factor.

摘要：

以去离子水为工质，流经直径0.5 mm、柱间距0.5 mm、柱高度分别为1.00、0.75、0.50、0.25 mm的圆柱组成的三维柱群板，板宽3.5mm、板长40 mm。测量通道内不同Reynolds数下的进出口压差及流量，研究微/小柱群内部分别在叉排和顺排时液体流动的流动特性。研究表明，当流动处于纯层流态时，微/小柱群内部流动阻力系数f与Re乘积（fRe）随着Re增加几乎不变;随着Re增加到超过100，除柱高为0.25 mm的柱群外，其余实验段fRe值随Re增加而缓慢增加，这是由于产生旋涡阻力、水流脉冲增强及频率加快导致的。对于柱高0.25 mm实验段，由于微/小尺度效应、柱群底面及柱表面粗糙度效应等导致了其fRe在Re超过150后呈快速振荡增加。微/小尺寸叉排柱群流动阻力远高于顺排柱群流动阻力系数，且柱高越高摩擦阻力系数越低。