部分负荷工况下水泵水轮机的空化特性

发布时间：2018-05-17 18:25

本文选题：水泵水轮机 + 部分负荷　；参考：《排灌机械工程学报》2017年08期

【摘要】：为研究部分负荷工况下水泵水轮机空化系数改变对内流特性的影响,采用RNG k-ε湍流模型和Schnerr-Sauer空化模型,对某抽水蓄能电站模型机进行了全流道非定常空化流动数值计算,并分析了机组处于不同空化阶段时的水力性能及内流状态.研究结果显示:逐步发展的空化会引起水力效率降低和轴向力显著增大;部分载荷时,空化产生的涡带起源于泄水锥处,呈螺旋形向下游低速运动;随着空化系数的减小,涡带形态逐渐由细变粗,低压区覆盖范围向外扩展,沿半径方向的速度变化更加急剧.在空化涡带旋进的过程中,流道内出现了严重的二次回流,主流沿着锥管壁面向下游推进,引发壁面的冲撞而引起激烈的振动,这种结果对机组的稳定高效运行非常不利.
[Abstract]:In order to study the influence of cavitation coefficient change on the internal flow characteristics of pump turbine under partial load condition, the RNG k- 蔚 turbulence model and Schnerr-Sauer cavitation model were used to calculate the unsteady cavitation flow in a pumped-storage power station model. The hydraulic performance and internal flow state of the unit at different cavitation stages are also analyzed. The results show that the gradual development of cavitation will lead to the decrease of hydraulic efficiency and the increase of axial force, and the vortex band generated by cavitation originated from the drain cone and moves downward at low speed with the decrease of cavitation coefficient. The shape of vortex zone gradually changed from fine to coarse, and the low pressure area expanded outwards, and the velocity along the radius changed more sharply. In the process of cavitation vortex band whirling, serious secondary reflux occurs in the flow channel, the mainstream is pushed downstream along the cone tube wall, which causes the wall collision and causes the violent vibration. This result is very unfavorable to the stable and efficient operation of the unit.
【作者单位】：兰州理工大学能源与动力工程学院;甘肃省流体机械及系统重点实验室;
【基金】：国家自然科学基金资助项目(51566009) 甘肃省自然科学基金资助项目(1310RJZA023)
【分类号】：TV734

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