中文摘要：

为揭示转速对泵作透平效率的影响规律,该文以一比转速为66,叶轮采用透平专用叶轮的离心泵反转作透平为对象,完成了900到2 100 r/min间隔300 r/min,共5个不同转速运行试验与数值模拟。结果表明：不同转速下,透平扬程与轴功率均随流量增大而增加,效率曲线先上升后下降。CFD计算值与运用比例定律理论计算值较吻合,但CFD不能完全客观反映变速对效率的影响。试验性能参数与运用比例定律理论计算值存在一定偏差,流量偏差最小,扬程偏差其次,轴功率偏差最大。额定转速运行时,试验最高效率为69.83%;降20%与40%转速运行时,效率较额定转速时分别下降了2.82%与6.34%。分析表明,降速对容积与机械效率呈负影响,而一定范围内升速对效率呈非线性正向影响。透平部分工况运行时,偏离额定工况越远,效率下降越明显,降速运行对提高效率效果越显著。在水力条件及强度均满足的前提下,透平尽量维持或略高于额定转速运行,有利于能源的高效利用。研究结果对透平高效经济运行具有参考价值。

英文摘要：

A reverse running centrifugal pump is one of the most convenient choices with lower cost in microhydropower development and industrial pressure energy recovery. One of the main limitations in utilizing pump as turbine（PAT） technique is that the PAT usually runs at part load for several months in a year due to insufficient water availability for the power production. Variable speed operation offers an effective solution to this problem. Pump manufactures normally do not provide performance curves of pump running in turbine mode, especially when working at variable speed condition. In addition, performance test may often be required to be carried out in order to accurately obtain the operation parameters before high power PAT working in industrial pressure energy recovery. Due to the limitation of the laboratory power capacity, the performance of rated rotational speed condition is often estimated through decreasing rotational speed in the test. It is difficult to accurately obtain the performance parameters of the rated condition. Therefore, experimental research at different rotational speed is useful to understand the correlations between PAT＇s performance parameters and rotational speed. In the present research, an open PAT test rig was set up. An electric eddy current dynamometer（EECD） was installed in the rig to measure and consume energy generated by PAT. And an automatic control system was used in the test to regulate rotational speed of PAT. The rotational speed of PAT was varied by adjusting the rotational speed of EECD. To study the effects of rotational speed on the performance, the operation of PAT was simulated by using computational fluid dynamics（CFD） technique at different speed ranging from 900 to 2100r/min with a step of 300 r/min. Through the comparison of performance curves obtained by experiment, we could find that the trend at different rotational speed was similar. The head and shaft power curves both increased with the increase of flow rate. And the PAT efficiency first increa