Abstract:Based on the earlier numerical calculation about an axial flow pump model at 0° installation angle, the same axial flow pump model was chosen and simulated at other various angles, and the performance was analyzed under steady and unsteady operating conditions. In the ANSYS CFX software, the standard k-ε turbulence model and scalable wall function were used with suitable mesh number and distribution. The difference between numerical simulation and experiment was compared and analyzed. Under the standard use of CFD tools, the accuracy and error characteristic of numerical simulation were analyzed in order to guide CFD technique to engineering application. When comparing with the experiment value, it is concluded that the predicted water head value by unsteady simulation is slightly higher, while that by steady simulation is lower. Generally speaking, the unsteady simulation accuracy is superior to the steady one, and the water head error can be controlled within 5%. The efficiency error for both methods can be controlled within 7%, and there is a relative fixed amplitude deviation for unsteady simulation, which can be used to guide the error correction of efficiency prediction. According to the unsteady calculation results, the streamline distribution of impeller and guider span surfaces, the blade span section line pressure distribution, and the variation of hydraulic loss with blade stagger angles and flow rate for different parts are analyzed. Under small flow rate condition, there exits a vortex jam phenomenon near the hub. Within the range of simulation operation conditions, the hydraulic losses for both guider part and outlet part will firstly decrease and then increase with the flow rate increasing.
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