Numerical calculation of optimal length of throat pipe in jet pump

The length of throat pipe is one of the important geometry dimensions affecting the efficiency of jet pump. In this paper, two kinds of conditions for determining the relative optimum length of throat pipe are proposed. Numerical simulation is applied to calculate the flow field in the jet pump with various throat pipe lengths and area ratios. The k-e double equations for turbulent flow are adopted and the relative optimal throat pipe length is determined according to the maximum efficiency. The results show that the optimal throat pipe length is closely related to the area ratio. The longer throat pipe length corresponds to higher area ratio. The formula for this relationship is established and verified by experiment data.