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The diagram shows the self-circulation process of the transfer pump. Is the work done the same if only the horizontal position of the transfer pump changes?
It’s different because the length of the pump inlet and outlet pipes has changed, resulting in a change in pipe resistance.
The total length of the pump inlet and outlet pipes remains unchanged, the height of the pump outlet remains unchanged, and the flow velocity remains unchanged; therefore, the resistance remains unchanged, and thus the total work done also remains unchanged. If there are other flow streams at the pump outlet in addition to its own circulation, the resistance at the pump inlet is different.
If only the horizontal position of the pump changes, why would the total length of the inlet and outlet change as well?
As can be seen from the diagram, it seems that a elbow has been added at the pump outlet, so the pipeline resistance should have changed.
The length of the pipeline, its direction, and the fittings remain unchanged; in this case, only the horizontal position of the pump changes
There isn’t much difference; if we’re being precise, the changes that occur at the same location on the same pump at different times are likely to be greater than the changes that occur in a horizontal position.
Take a centrifugal pump as an example: even if its position changes horizontally, the flow rate, head, and fluid remain unchanged, so the useful power stays the same! If the length of the pipe is taken into account, it’s actually the same; when it comes to pipe resistance, one only needs to consider whether there is any fundamental change in the pipe length, and such changes can be ignored! In industrial production, when determining the installation location of a pump, the work done by the pump is not taken into consideration; priority is given to keeping the pipelines as short as possible, as well as to facilitating operation and maintenance.
The amount of work done by a pump is related to the flow rate; when the flow rate is the same, the amount of work done is also the same.
Is your circulation process simply the liquid in the pipeline being pumped to facilitate circulation? Didn’t it go into the storage tank? ? If it does not enter the storage tank but only circulates within the pipeline, and the length of the pipeline, the number of bends, the elevation, etc., are all exactly the same, then the location where the pump is installed makes no difference.