Pump (source code)
= Pump
A <pump> supplies mechanical <energy> to a <fluid> so that it can flow against resistance or gain elevation. For a steady incompressible stream, a rise in <pressure> $\Delta p$ at similar inlet and outlet heights and speeds represents useful fluid <power> $P=Q\Delta p$, where $Q$ is the <volumetric flow rate>. Differences in <kinetic energy> and gravitational <potential energy> must be included when those conditions do not hold.
A real installation chooses its flow through the interaction between the pump's pressure-flow response and the connected passages. More resistance generally shifts the <pump operating point>, so the nameplate or rotational speed alone does not determine <mass flow rate>. Measuring inlet/outlet <pressures>, flow and supplied mechanical <power> separates useful fluid output from dissipative losses. A <centrifugal pump> uses a rotating impeller; a displacement device instead moves a defined volume during a cycle, with leakage and compressibility affecting the actual delivery.
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