大型立式轴流泵叶片进口流场及其对水泵影响研究

分析各因素对大型立式轴流泵叶片进口流态的影响,研究该断面流场的形成机理。提出叶栅对进口流态反作用和相互自动调整的观点,即如果叶栅来流非均匀轴向,叶栅过流特性会反过来影响来流流态并调整达到平衡。结果表明,立式轴流泵叶片进口流场既非轴向,又非均匀,不符合常规假设。用五孔探针实测叶轮直径D=1.64m轴流泵叶片进口流场,证明了理论分析的正确性。分析叶片进口流态对水泵性能、导轴承偏磨和间隙气蚀的影响,提出改善流态的方法。成果对改进轴流泵及其进水流道设计理论和方法,提高运行性能具有重大意义。

STUDY ON FLOW FIELD IN BLADE INLET OF LARGE VERTICAL AXIAL-FLOW PUMP AND ITS INFLUENCE ON PUMP

Influence of each factor on blade inlet flow of a large vertical axial-flow pump is analyzed, formation mechanism of flow field in the cross section is studied. The idea is put forward that the blade cascade adversely effects the inlet flow and the flow adjusts automatically, that is to say, if inlet flow of cascade is not axial even flow, the characteristics of cascade will react on the flow and reach equilibrium with the flow. The results indicate that the flow field in blade inlet of large vertical axial-flow pump is neither axial nor even, different from normal assumption. The flow field in blade inlet of pump with impeller diameter D=1.64 m is measured with five-hole probes, which field in inlet of blades on performances of pump, partial wearing of guide bearing and gap cavitation are analyzed and improvement methods of the flow are put forward. Results mean much to improvement of design theories and methods on axial-flow pump and its suction passage and increasement of operation performance.