拟塑性幂律流体的掺气管输减阻的数值模拟

Numerical Simulation of the Drag Reduction of Pseudo-plastic Power Law Fluid with a Small Quantity of Gas on Pipeline Transportation

根据幂律流体的本构方程，采用欧拉法建立了空气-幂律非牛顿流体两相流动方程，在此基础上对拟塑性幂律流水煤浆的掺气管输的减阻效应进行了数值计算及理论分析。计算及理论分析表明，在高黏幂律流体中，采用适当方法掺入少量气体可以达到降低流动阻力的效果。减阻效应出现在输入气液体积比小于0．08的范围内，当输入气液体积比为0．0125～0．0313时，减阻效果最好，此时减阻率可达13％以上。此外，气泡直径也对减阻效果有一定影响，为了获得好的减阻效果，应采用适当方法将掺入流体的空气所形成的气泡直径控制在1～2mm以内。

According to the constitutive equation of power law fluid, the theoretical model of gas-power law fluid two-phase flow is developed and the flow characteristic and drag reduction of the pseudo-plastic power law fluid with gas on pipeline are numerically simulated. The numerical simulation shows that the flow resistance of power law fluid on pipeline can be reduced when a small quantity of gas is input into the fluid. The input volume ratio of gas-to-liquid has an evident influence on the drag reduction. The drag reduction exists in the range of an input gas-to-liquid volume ratio of 0～0.08. The effect of the drag reduction is best when the input volume ratio is in the range of 0.0125～0.0313, and the efficiency of the drag reduction hits over 13%. In addition, the size of gas bubbles also influences drag reduction. The diameter of gas bubbles should be limited in a range of less than 1 or 2 millimeters for a better drag reduction.