Effect of changes in centrifugal pump impeller size on flow rate and pressure
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We have a double-suction impeller here; the pump’s specifications are as follows: DFSS500-700, flow rate: 2898 m3/h, head: 53 m, power: 560 kW, pump speed: 980 r/min, efficiency: 86%, NPSH: 6.5 r. The fluid being transported is clean water. Now we have a new impeller, but its parameters aren’t quite right. I would like to know if this will affect the flow rate. The parameters of the new impeller are: impeller diameter of 670 mm, impeller channel width of 122 mm. While the original impeller had a diameter of 655 mm and a channel width of 135 mm. I’d like to know what the impact on the flow rate will be after installing the new impeller. The main change is that the impeller diameter has increased while the channel width has decreased. Waiting for a response
When comparing impellers, it is necessary to consider not only the diameter and outlet width but also the inlet diameter, number of blades, blade shape, etc. Based on the diameter and outlet width you provided, it seems that the impellers were not designed from the same drawing, so it is impossible to determine the changes in flow rate and head.
The original poster can check the formula for specific speed and do the calculations; there should be a slight increase in flow rate and pressure
The number of leaves and the shape of the leaves are the same; they weren’t created from a single image
Hehe, the size of the mouth ring is the same, as are the number and shape of the blades; they are manufactured after being measured by the producer, so they’re not original parts
The impeller diameter is proportional to the flow rate, I’m not entirely sure about this; please forgive any mistakes
The inlet diameter does not refer to the diameter of the mouth ring, but rather to the diameter of the inlet through which the liquid passes. For the measured impeller, its diameter and flow channel must remain identical to those of the original unit in order to maintain consistent performance. With such a large difference, it’s impossible to determine in which direction performance will develop; however, a larger diameter should result in a higher head, while a narrower opening may lead to a lower flow rate.
The cutting law states that flow rate is proportional to the impeller diameter. As the flow rate decreases, efficiency should drop, and hydraulic losses should increase