Numerical Analysis of Pressure Pulsation for a Bidirectional Pump under Positive and Reverse Operation

Bidirectional pump holds great promise in a wide range of applications since it could realize the function of drainage and irrigation simultaneously. A bidirectional pump with high specific speed was designed and 10 groups of performance tests, under different setting angles, including both positive and negative directions, were conducted. Numerical simulations were then performed to analyze the variation principle of internal pressure pulsation in flow passage and both the front and the back sides of the blade and guide vane. Results show that the optimum operation point was shifted and the performance declined under reverse operation. The maximum pressure pulsation amplitude occurred to the vicinity of the blade's inlet edge under both positive and negative operations. The main pulsation frequency was the blade passing frequency while it was four times of shaft rotation frequency in the rotatory zone, which was equal to the number of guide vanes. The guide vane has a significant effect on the pressure pulsation variation. The pulsation amplitude had a higher value while the pump was in its negative operation rather than positive. These results could provide valuable insight for reducing the pressure amplitudes in the bidirectional pump.