摘要
利用COMSOL Multiphysics软件,选取不同滑移长度对水的泊肃叶微流动进行数值模拟,得到入口段长度、流量和摩擦阻力系数随滑移长度的关系,分析了微流动与宏观流动的差别及不同的壁面条件下流动参数的差异.结果表明:无滑移壁面和亲水壁面下,微流动入口段长度和目前的经验公式吻合;流量值小于理论值,但与压差依旧成正比;摩擦阻力系数大于宏观理论值.典型无滑移壁面和亲水壁面下的流动特性基本相同;疏水壁面的入口段长度和无滑移壁面、亲水壁面相近,但流量和摩擦阻力系数有差异;超疏水壁面下流动特性和其他三种壁面差异很大.进口速度一定时,入口段长度随滑移长度成"阶梯式"增长;流量随滑移长度的增加而增大;摩擦阻力系数随着滑移长度的增加而减小.
COMSOL Multiphysics software is used to simulate the microflow of the water under different slip length in a microtube firstly. Then the relationship of the entrance length, flow rate and friction factor between slip length are concluded, the difference between microflow and macroflow are compared and the flow characteristics of four typical wall conditions are discussed. It reveales that： in the condition of no-slip and hydrophilic wall, the entrance length is in agreement with the empirical value; the flow rate is less than the value calculated by Poiseuille＇s formula while it is still proportional to pressure difference; the friction factor is greater than macroscopic theoretical value. The flow characters of the hydrophilic wall condition is nearly the same with the no-slip wall condition; the entrance length of the hydrophobic wall condition is near to the no-slip wall condition and hydrophilic wall condition while there are some difference between the flow rate and friction factor; the flow characters of the superhydropholic wall condition are different from another wall conditions distinctively. With the growth of slip length, the entrance length increases as a ＂ladder＂ mode and the flow rate increases slightly while the friction factor decrease.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2017年第12期2619-2625,共7页
Journal of Engineering Thermophysics
基金
中央高校基本科研业务费专项资金项目(No.2016XS107)
关键词
滑移长度
泊肃叶微流动
流动特性
数值模拟
slip length
Poiseuille microflow
flow characteristics
numerical simulation
