几何尺寸对矩形微通道液体流动和传热性能的影响.pdfVIP

  几何尺寸对矩形微通道液体流动 和传热性能的影响 刘赵淼 逄 燕 申峰 (北京工业大学机械工程与应用电子技术学院 北京 100124) 摘要：基于连续介质方法数值研究了液体在不同几何结构微通道中的流动和传热性能。在相同热边界条件下，通 过比较水力直径、通道长度和宽高比等几何参数对液体微流动的影响，得到各参数对泊肃叶数(Po)和努塞尔数(Nu) 的影响关系。研究发现：截面宽高比越大，Po 数越小，且雷诺数对泊肃叶数基本无影响；雷诺数(Re)小于约 500 情况下，水力直径小于约0.545 mm 时，Po 数随水力直径减小而减小，水力直径大于约0.545 mm 时，水力直径变 化对Po 数基本无影响；Po 数不随通道长度变化而变化，但略受流动雷诺数影响；在Re=20~1 800 ，Nu 数正比于 水力直径和宽高比，但是通道长度对Nu 数的作用受流动Re 数的影响；在通道材料和流动介质相同的条件下，Nu 数和Re 数之间的关系受通道几何参数的影响，并且拟合得到其关系式。 关键词：微通道 传热 流动 几何结构 中图分类号：O351 EFFECTS OF GEOMETRY ON THE LIQUID FLOW AND HEAT TRANSFER IN MICROCHANNELS LIU Zhaomiao, PANG Yan, SHEN Feng (College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing, 100124) Abstract ：The geometric effects on the liquid flow were investigated in microchannel based on the numerical simulation method. Effects of geometry were shown obviously on the microflow by comparing the results of different geometric characteristics covered hydraulic diameter, length and aspect ratio. Thermal boundary conditions are same for different cases in the numerical simulation. The effects of geometric parameters on the Poiseuille number and the Nusselt number have been investigated. The Poiseuille number decreases with the increasing of the aspect ratio while the Reynolds number has no effect on it for the same aspect ratio microchannels. For Re500, when the hydraulic diameter D 0.545mm, Po decreases with the D , but Po does not change when D is larger. The length h h h of the microchannel has no effect on Po