扩散器结构与喉管长度对喷射泵性能的影响

Effect of diffuser structure and throat length on jet pump performance

为了改进喷射泵性能,采用等速度或等压力变化方法设计喷射泵的扩散器,利用正交试验设计方法设计喷射泵的喉管长度、扩散器角度和型线等3种参数,每种参数取3种水平并考虑交互作用,得到27种组合.数值模拟得到每种结构组合下喷射泵的性能,并进行流场分析,研究结构参数对内部流场的影响.方差分析表明,结构参数间交互作用对喷射泵性能具有显著影响,在喷射泵的设计中应予以重视;和传统锥形扩散器相比,等速度或等压力变化扩散器均能产生较为均匀的速度和压力梯度,能获得较好的性能并显著缩短喷射泵的长度;喉管和扩散器的最优组合为:喉管长度为其直径的6倍,扩散器型线选择锥形,扩散角取8°.

New diffuser profiles designed by constant rate of velocity or pressure change method （CRVC/ CRPC） were adopted to improve the jet pump performance. The orthogonal design was used to arrange the structure combinations of jet pump. The throat length, diffuser angle and profile were chosen and each factor had three levels. Considering the interactions between factors, 27 combinations were obtained and simulated to gain their performance. The effect of structure parameters on the flow details was studied. The results from the variance analysis show that all the factors and interactions have great influence on the pump performance. The interactions among the geometric parameters should be considered during jet pump optimization. The CRVC or CRPC diffuser produces a smoother and more uniform velocity and pressure gradient along the axis than the conical diffuser. Combining with appropriate throat length, the CRVC or CRPC diffuser could improve the pump performance and shorten the total pump length considerably. The most desirable combination consists of a throat with its length 6 times of its diameter and a conical diffuser with angle of 8.