射流泵最佳参数的确定方法

Method of Optimal Parameter Ascertainment of Jet Pump

根据能量守恒原理得出了射流泵效率计算公式 ,再利用多元函数极值原理给出了射流泵最优参数方程 ,求解并给出了射流泵基本性能包络线和效率包络线 ,分析了摩擦损失系数和密度比对最优参数的影响 ,确定出最优化面积比值。理论计算结果表明 :在等密度体系和Petrie给出的摩擦损失系数条件下 ,最优面积比为 0 .2 80 ,与文献 [8]中给出的实验结果相近 ;摩擦损失系数是影响射流泵效率的主要因素 ,密度比对最优工作点有一定的影响 ;最优面积比只与摩擦损失系数有关 ,而与流体间的密度比无关。

The formulation of efficiency for the jet pump is derived. Then the optimal parameter equation for jet pump is given out based on the multi variable limitation theory. The equation is solved and the elementary property convex line and efficiency convex lines are given out. The effects of friction loss coefficient and density ratio on the optimal parameter are analyzed. The optimal area ratio is got too. The results of theory analyzing show that under equal density system and with the friction loss coefficient given out by Petrie, the optimal area ratio is 0.280, which is appropriate to experimental result of [8]. The results show that the friction loss coefficient is the key factor affecting the efficiency of pump. The density ratio has a moderate effect on the property of jet pump. The optimal area ratio is singly related with friction loss coefficient, and it is not related to the density ratio of fluids. The conclusion is helpful to the practice usage.