凝胶推进剂锥形管道流动特性数值分析

Numerical analysis on flow property of gel propellants in tapered round pipes

对凝胶推进剂在锥形圆管中的流动过程进行了数值计算,研究了锥形圆管收敛角对轴向速度、平均表观粘性、压降的影响关系,得到了凝胶推进剂在锥形圆管中的轴向速度与平均表观粘性分布。计算结果表明,随着收敛角的增大,出、入口截面平均表观粘性降低幅度不断增大,出口截面平均表观粘性不断减小至近牛顿粘性水平η_∞;并且,粘性的减小是以增大压降需求为前提的,当角度改变达某定值之后,角度的改变引起粘性的变化将不再显著。结果表明,圆管收敛角是影响粘性变化的一个重要参数,粘性变化与压降需求之间存在最佳结合点。

The flow process of gel propellants in tapered round pipes was numerically simulated. The effect of the tapered round pipe convergence angle on the axis velocity, mean apparent viscosity and pressure drop was studied. The axis velocity and mean apparent viscosity fields of gel propellants in tapered round pipes were obtained. The results show that the decrement of the mean apparent viscosity in the outlet and the inlet increases with the increasing of convergence angle. The mean apparent viscosity of the outlet decreases significantly and its value is limited by the Newtonian viscosity η∞; On the other hand, the decreasing of viscosity resuits in an increase of the pressure drop. In addition, the viscosity no longer decreases significantly due to the convergence angle change when it reaches a limitation. Therefore, the pipe convergence angle is an important parameter that affects the viscosity, there exist an optimum matching point between the viscosity change and the pressure drop