Optimization of water jet pumps using numerical simulation

A water jet pump is one of the best examples of a device in which liquid-jet mixing phenomena occur. Since such mixing processes are complex, the choice of turbulence model for accurate prediction of performance of the pumps is important. The aim of this numerical simulation study is to investigate effects of parameters such as the jet pump area ratio, nozzle position, and length of the mixing chamber on the pump performance and then to perform an optimization of six different water jet pumps according to these parameters, taking energy efficiency as a criterion. In the optimization procedure, the transition SST model (-Re) was used because it provided more accurate results among the four advanced turbulence models. The numerical results obtained with the model were compared with experimental data of the jet pump with the same geometry at the boundary conditions available in the literature and it was seen that maximum deviation in the pump efficiency at the optimum operating conditions was approximately 10%. As a result, the maximum numerical efficiency is found to be 34.6% at the area ratio of 4.61 and a pressure ratio of 0.277.