Regarding the issue of excess pressure at the outlet of the centrifugal pump
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The flow rate is 10 cubic meters, and the required head in the pipeline is 10 meters. The pump outlet is connected to a swirl chamber; the desired feed pressure is 0.1 MPa. It is assumed that the medium is plain water at room temperature. Should I choose the model based on a flow rate of 10 and a head of 20? The remaining pressure of 0.1 MPa will cause the flow rate to be higher, shifting the performance point to the right; as a result, the actual flow rate will be greater than 10 cubic meters, and the head will be less than 20 meters.
This is related to resistance and can be calculated. But a head of 20 meters might not be necessary; just for reference.
Thank you for the reply. I can calculate the resistance; I just don’t understand the issue of residual pressure. Also, the numbers I mentioned are just arbitrary values, used merely to illustrate the question I want to ask; they have no practical significance. I just don’t understand why, when the actual head is greater than the calculated head, the pump will have a higher flow rate. But for the outlet excess pressure, does it also mean that the calculated head is greater than the pipeline head (at the inlet of the cyclone)? Could this result in an excessive flow rate, causing the flow to be higher than expected while the head pressure is lower than expected?
It won’t happen; otherwise it would be a problem with the operation. It’s best to clarify whether it’s a problem that occurred on site or a concern related to the design, so as to facilitate discussion.
There were no issues on-site; I know that this calculation is correct and there will be no problems with using it. I just have a problem with my own understanding of this, so I’m here to ask for advice.
My understanding is that the head calculation should take into account the residual pressure at the outlet
Calculate it, taking the inlet pressure and outlet pipe resistance into account