斜式泵装置负扬程飞逸过渡过程内部流动特性分析

Analysis of Internal Flow Characteristics in Negative Head Runaway Transition Process of Inclined Pump Device

为了研究斜式轴流泵装置正转飞逸过渡过程的水动力特性,采用数值模拟与模型试验相结合的方法分析了1座斜30°轴流泵装置正转飞逸过渡过程中泵装置的内外特性。结果表明,-3.33 m扬程下水泵正转飞逸转速为383.0 r/min,是额定转速的2.72倍,远超同扬程下反转飞逸转速;泵装置达到飞逸工况后扭矩并不恒为0,而是围绕0波动;随着叶轮转速的增加,在出水流道中隔板两侧断面的流量存在明显差异,达到正转飞逸工况后两侧流量相差3倍,偏流程度与转速有关;偏流现象宏观上表现为中隔板两侧流量不均,微观上表现为两侧水压脉动特性迥异;出水流道中隔板两侧的偏流是由导叶出口剩余环量引起的。研究结果对今后斜式轴流泵装置的设计具有重要的参考意义。

In order to study the hydrodynamic characteristics of the forward runaway transition process of the inclined axial flow pump device, taking an inclined 30°axial flow pump device as the research object, the internal and external characteristics of the pump device in the forward runaway transition process were analyzed by the combination of numerical simulation and model test. The results show that the forward runaway speed of pump is 383.0 r/min at the-3.33 m lift, which is 2.72 times of the rated speed, far exceeding the reverse runaway speed under the same head;After the pump device reaches the runaway condition, the torque is not constant at 0, but fluctuates around 0;With the increase of impeller speed, there is an obvious difference in the flow on both sides of the partition in the outlet channel. After reaching the forward runaway condition, the flow difference on both sides is 3 times, and the degree of bias flow is related to the speed;The existence of eccentric flow phenomenon is characterized by uneven flow on both sides of the middle diaphragm macroscopically and different water pressure pulsation characteristics on both sides microscopically;The bias flow on both sides of the diaphragm in the outlet channel is caused by the residual circulation at the guide vane outlet. The research results have important reference significance for the design of inclined axial flow pump in the future.