Impeller cutting
Thread Content
Multi-stage feed water pump, the first-stage impeller is a double-suction impeller, there are 7 secondary impellers in total, the diameter of the secondary impeller is 326.5, the initial flow rate is 484, the lift is 1751, the impeller is cut to 302, the flow rate is 484, and the lift is 1218. How can the impeller outlet width be less than 1 after cutting? Why is it so different from the value calculated by the cutting calculation formula?
The increase in impeller outlet width is less than 1
Only the secondary impeller is cut, the first impeller is not cut
I haven’t understood it after reading it for a long time. What do you want to express?
According to the calculation formula of impeller cutting, it should not change so much. Now I can’t find the reason. I would like to ask what may be the reason for this result.
Do you know what the original performance curve looked like? If the curve is steeper, what is the original lift when the pump is opened to 530 cubic meters?
Only the runner is cut, or the front and rear covers are cut together? All seven secondary impellers were cut?
If the flow rate is not calculated, the actual lift should not be so low when the car reaches 302, and there is no car in the first round. Is there a complete curve? The flow rate before the car is about 600. What is the diameter of the impeller inlet? Use the German algorithm to calculate it. What we used was quite accurate. We only machine the blades of the impeller, not the cover. Please refer to it.
The seven secondary impellers are all cut, and the front and rear cover plates are 8mm longer than the blade side.
Curve before cutting, impeller inlet width 180
We calculate based on the lift at the intersection point generated on the curve chart. Your estimate of this parameter should be calculated based on the lift at about 520 cubic meters.