Is the trend of impact on the characteristic curve of the pipeline the same when reducing the inlet or outlet valve of the water pump?
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Is the trend of impact on the characteristic curve of the pipeline the same when reducing the inlet or outlet valve of the water pump? Does it all result in an increase in the frictional losses along the pipeline, which causes the pipeline’s characteristic curve to become steeper? This in turn leads to a shift of the pump’s operating point to the left, resulting in a decrease in flow rate and an increase in head pressure?
Adjusting the inlet and outlet valves of the pump has no effect on the characteristic curve of the pipeline. I suspect your question isn’t clear enough on its own.
This post was last edited by WSRYLONG on 2015-10-28 09:07. Generally, the inlet valve of the small pump is not adjusted. The actual head of a pump can be considered to consist of two parts: the suction section and the discharge section. Reducing the inlet valve of the pump increases the resistance in the suction section, while reducing the outlet valve increases the resistance in the discharge section. Both will increase pipeline resistance, but the effects differ slightly: reducing the inlet valve of the pump will lower the outlet pressure of the pump ； Closing the pump outlet valve will increase the pressure at the pump outlet. Both will reduce the flow rate. .
Thank you all for your prompt replies. :handshake
I would like to ask a question about the third floor: where can I find examples to support it, or the theoretical derivation process?
Hehe, as for the theoretical derivation process, I’m not very familiar with it either; it’s probably quite complicated. As for finding examples to prove it, it’s very simple – just try it yourself; it takes only a few minutes.
What I mean is that the inlet valve of the pump is installed on the pipeline in the suction section of the pump, while the outlet valve is installed on the pipeline in the discharge section; therefore, reducing the valve opening increases resistance, which in turn affects the characteristic curve of the pipeline. I’m not sure if it’s clear enough?
I think what you say is correct
Okay, I got it. Thank you for the reminder
I would like to ask, in which book is this situation described?
This is basic knowledge about water pumps, and it should be included in most books on water pumps. There are many available for download online; just do a search.