幂律型凝胶推进剂管路中的流动特性

Flow behavior of power law model gelled propellant in the pipe

关键词:  胶凝推进剂  管路  流阻  流动特性

Key words:  Gelled propellant  Pipe line  Flow resistance  Flow characteristic

摘要:

为研究幂律型凝胶推进剂在管路中的流动特性,对直径4~14 mm,长度0.5~2.0 m的一组直圆管和直径6 mm,弯角20°~90,°弯曲半径比1~5的一组弯管,在1~30 m/s的流速下,用3种模拟液进行了实验和仿真。对收缩角10°~50°,收缩比3~1.5的收缩和扩张管,在流速1~30m/s的范围内,用模拟液进行了仿真。结果表明,其它条件相同时,管长、弯角、流速和收缩比增加,流动损失增加;凝胶推进剂在管路中呈"柱塞"形流动,其特性取决于流速、流变指数和稠度系数;管壁附近的剪切速率最大,表观粘度最小;弯管内侧剪切速率小于外侧剪切速率;收缩型截面中,剪切速率逐步增大,粘度逐步降低;突缩和突扩截面存在低速回流区。

Abstract:

In order to study the flow characteristic of power law model propellant in the pipe,three type propellant simulants were used in experiment and numerical calculation with different velocity for a group of straightness pipes that have different diameter and length as well as a group of bend pipes that have different bend angle and bend radius ratio.Simulants were used in calculation in the different velocity for contractive pipe and expansionary pipe that have different contractive angle and contractive ratio.The results showed that the increase of pipe length,curving angle,velocity and contractive ratio would lead to the increase of the flow losses on the same conditions.There is a plug flow area in the pipe.The characteristic of plug flow area is dependent on the propellant velocity,power law exponent and the consistency index.Near the mural area of the pipe,the shear rate is the largest and the apparent viscosity is the minimum.The shear rate at inboard wall of the bend pipe is smaller than the one at the pipe outboard.Near the mural area of the contractive pipe,the shear rate increases and shear viscosity decreases.There is a lower velocity swirl area in contractive pipe and expansionary pipe.