用表观黏度计算幂律流体摩阻的方法及其应用

A method of calculating the pressure-drop of power-law fluid by apparent viscosity and its application

在计算非牛顿含蜡原油管道输送的沿程摩阻时,通常采用幂律流体的摩阻计算公式.通过理论分析和算例验证表明,若紊流时雷诺数的计算采用管壁处的表观黏度,层流时雷诺数的计算采用距径向位置0.7788R处的表观黏度(R为管道半径),则圆管中幂律流体的流动摩阻可以用牛顿流体的公式来计算.此方法得到的结果与按传统幂律流体计算方法所得结果接近.采用该方法为热油管路特性的分析提供了方便.

When the pressure drop of non Newtonian waxy crude in pipeline is calculated, the calculation formulae for power law fluid are commonly adopted. In this paper, a new approach is put forward independent of power law formulae. It is verified theoretically and illustratively that if the Reynolds number is calculated on the basis of the apparent viscosity at the wall for turbulent flow or at the radial position of 0.7788 R (R is the radius of the pipeline) for laminar flow, then the pressure drop of power law fluid can be calculated by using the formulae for Newtonian fluid. There is an error less than 3% between the two results calculated by the new method and traditional one separately. This new method makes the characteristic analysis of waxy crude piping easier.