It is well known that there is a positive slope region in a mixed-flow pump head curve with high efficiency at design point. Several techniques have been developed to enhance pumping stability. For the purpose of enhancing pumping stability using a more simplified method, the inlet wall barrier (IWB) was proposed in this paper. The experimental investigation was done to make clear the effect of inlet wall barrier on the pump characteristic and the internal flow condition. The variation of pump performance by the change of inlet wall barrier size and location were investigated. As a result, it was determined to be the most effective IWB condition for reducing the positive slope region. Furthermore, velocity distribution profiles and wall pressures were measured in order to clarify the reason why characteristic curve was improved by IWB. In this paper, we showed the effects of IWB on the pump performance and the reason why the IWB enhanced pumping stability through changes in the internal flow condition.
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