A Method for Determining the Runaway Speed ​​of an Inclined-Axis Pump at Different Blade Angles

Abstract

The invention discloses a method for determining the runaway speed of an inclined-axis pump at different blade angles, comprising the following steps: establishing a three-dimensional CFD model when the blade angle of the inclined-axis pump is 0°; The internal flow state of the inclined-axis pump under the speed condition; use specific formulas to obtain the hydraulic torque, friction torque and total torque of the inclined-axis pump rotor; use 10% of the rated speed as the speed increment to calculate multiple reverse speeds The internal flow state of the inclined-axis pump in the working condition generates a torque-speed relationship curve; the runaway speed of the inclined-axis pump is obtained by reversing the speed on the torque-speed relationship curve where the torque is 0; it is obtained through a specific relationship Runaway speed at other blade angles. On the basis of embodying the characteristics of the inclined-axis pump, the present invention gets rid of redundant methods such as transient multi-time step CFD calculation and torque-time derivative calculation for the calculation of the runaway speed of the existing water pump, and significantly improves the runaway speed of the inclined-axis pump Computational efficiency and precision.

Description

technical field [0001] The invention relates to the technical field of water conservancy engineering, in particular to a method for determining the runaway speed of an inclined-axis pump at different blade angles. Background technique [0002] The runaway speed refers to the maximum reverse speed reached when the rotor of the water pump unit reverses under the action of the working water head under the condition of power failure of the motor. Accurately obtaining the runaway speed of the water pump unit plays an important role in correctly setting the anti-runaway measures and ensuring the safe operation of the unit. [0003] The runaway speed of large water pumps often requires the use of pump model tests in the laboratory to first obtain the unit runaway speed of the model pump, and then convert the runaway speed of the prototype pump through similarity law. However, this method has high cost, long period, high risk, and the conversion accuracy is greatly affected by bear...

AI Technical Summary

Problems solved by technology

Especially for oblique axial flow pumps, due to the oblique arrangement of the pump shaft, the torque M is not only related to conventional parameters such as flow rate and speed, but also related to the inclination angle of the pump shaft, so the calculation is very complicated; and, the oblique shaft The vane angle of the pump generally includes 9 angles of -8°, -6°, -4°, -2°, 0°, +2°, +4°, +6°, +8°, ​​so the inclined axis pump The calculation of runaway speed at all blade angles usually takes more than three months, which is extremely time-consuming

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