摘要
对9种弯径比的8 mm直径90°弯曲圆管,在7种雷诺数条件下的流动过程进行了数值实验研究,得到了弯管内流动的压力和速度分布以及局部阻力系数同弯径比和雷诺数之间关系的经验公式。结果表明,压力和速度在弯头部分沿轴线呈非线性分布,且随雷诺数增大非线性更加明显,而且这种非线性所表现出的压力损失是由于压力在弯头部分内、外壁面不一致分布造成的二次流所引起;同时,凝胶推进剂在弯管内流动的最大速度点出现在靠近弯管外壁,且沿着流动方向和流动速度的增大,最大速度点的偏离更加明显。因此,对于小雷诺数条件下的凝胶推进剂流动,需关注弯管内壁可能出现的胶凝剂沉降现象。
To evaluate the influence of the various bend diameter ratio Rc/R and velocity on the flow property of gelled propellants in pipe-bending pipe, the 3 D governing equations of the steady, incompressible, isothermal, laminar flow of a power-law, shear- thinning gel propellants in pipe-bending pipe were formulated, discretized and solved. A SIMPLEC numerical algorithm was applied for the solution of the flow field. Numerical investigation on a series of sharp 90°pipe-bending pipelines with nine kinds of bend diameter ratio and the inner diameters of 8 mm were conducted under the condition of seven Reynolds numbers. The pressure and velocity distributions were obtained. The empirical equation of local resistance coefficient for numerical experiments was conducted, providing the interrelations between the best bend diameter ratio and flow velocity in engineering design. The results indicate that the pressure and velocity distributions were non-linear, which became tremendous with increase of Reynolds nun-alters. The results sug- gest that the dot of maximum velocity occur at the wall outside of a bending pipe, which is nearer to the wall outside of a bending pipe along the flowing direction and increasing velocity. The phenomena of particle sedimentation should be taken into account to investigate the flowing behavior of gelled propellants in pipe-bending pipes under the condition of lower Reynolds numbers.
出处
《固体火箭技术》
EI
CAS
CSCD
北大核心
2011年第6期739-744,共6页
Journal of Solid Rocket Technology
基金
国家重大基础研究发展计划(613102)
关键词
凝胶推进剂
弯管
流动特性
数值实验
gelled propellant
curved pipe
flow property
numerical experiment
