Method for predicting necessary net positive suction head of axial flow pump based on pump unit

Abstract

The invention provides a method for predicting a necessary net positive suction head of an axial flow pump based on a pump unit, and belongs to the technical field of pumping station projects. Based on the calculation of a three-dimensional steady numerical value of an axial flow pump device, a numerical solution method is adopted to predict the necessary net positive suction head of the axial flow pump of the pump unit under multiple working conditions; the method is simple and convenient, the cost is low, the time-consuming is short, and the necessary net positive suction head of an axial flow pump station under any working condition can be predicted, so that the accidental working condition that the physical model test is not measured or the pump station is running can be made up. The method for predicting the necessary net positive suction head of the axial flow pump based on the pump unit provided by the invention helps to compare the cavitation performance of the axial flow pump device under different hydraulic models, helps to the safe and stable operation of an actual pumping station, avoids cavitation of the axial flow pump station, and achieves the purpose of ensuring the safe and stable operation of the axial flow pump.

Description

technical field [0001] The invention relates to a method for predicting and evaluating the cavitation performance of an axial flow pumping station, especially for an axial flow pumping station operating under multiple working conditions, and belongs to the technical field of pumping station engineering. Background technique [0002] Axial flow pumping stations are widely used in engineering fields such as farmland irrigation, flood control and drainage, and water transfer across river basins. The cavitation performance of axial flow pumping stations is a key factor affecting the safe and stable operation of axial flow pumping stations. When selecting axial flow pumping stations The cavitation performance physical model test of the pump device is often carried out according to the operating head of the pumping station to obtain the necessary NPSH of the axial flow pump at different heads, and provide reference for whether the cavitation performance of the axial flow pump meets...

AI Technical Summary

Problems solved by technology

However, in the actual operation process, when the inlet water level of the axial flow pump station is lowered or it is operated under high flow conditions, cavitation may occur inside the axial flow pump, resulting in a decrease in the efficiency of the axial flow pump device, a decrease in the head, and easy to cause axial flow. Pump vibration and noise. If the axial flow pump station runs under cavitation conditions for a long time, its flow-passing parts will be seriously damaged. At this time, the physical model of the pump device has not been subjected to cavitation tests for this working condition, so it is impossible to obtain this working condition The necessary NPSH of the axial flow pump during operation, it is impossible to judge whether the axial flow pump device can operate safely and reliably at this time

[0003] At present, the method of determining the necessary NPSH for axial flow pumps mainly adopts physical model tests, but the test cost of physical model tests for axial flow pump devices is high, time-consuming, and low in repeatability. The cavitation test of the physical model of the pump device has not been done in the small pumping station, so it is difficult to accurately judge the necessary NPSH during the operation of the actual axial flow pumping station, and there are potential safety hazards for the safe and stable operation of the axial flow pumping station

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