Numerical simulation and analysis of unsteady flow characteristics in centrifugal pump volute

The unsteady flow in a centrifugal pump is numerically simulated by using the RNG k-Ε turbulence model and the Zwart-Gerber-Belamri cavitation model. The influence of condensation coefficient of the cavitation model on numerical simulation is analyzed. According to the experimental result, the value of condensation coefficient is modified. The calculated variation of pump head with the available net positive suction head is in good agreement with the experimental data, so the accuracy and reliability of the numerical modal and method are verified. The results demonstrate that the dominant frequencies of pressure fluctuation in the volute at operating conditions of non-cavitation and cavitation are both the blade pass frequency. The cavitation has great influence on pressure fluctuation in volute. The maximum amplitudes of pressure fluctuation appear at the tongue of the volute and the first section of the volute for non-cavitation and cavitation conditions, respectively. It is caused by the strength of vortex enhances at cavitation condition and changing with time, which disturbs the flow in the first section. © 2015 Journal of Mechanical Engineering.