Pump head and outlet pressure
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I have been thinking about a question lately: what is the relationship between the head of a centrifugal pump and its outlet pressure? For example: If a centrifugal pump has a head of 100 m and the density of the fluid it transports is 1500 kg/m3, what is its outlet pressure? Is the outlet pressure equal to head * density * g?
Head is an inherent property of a pump; it is independent of the medium. Outlet pressure, on the other hand, is related to the medium, as can be seen from various formulas in chemical engineering principles
The head of a pump is equal to the pressure difference between the inlet and outlet of the pump multiplied by 10.2*9.8 divided by the specific density; therefore, the outlet pressure is related to the inlet pressure. The head represents the increase in pressure generated by the pump, and it has no direct relationship with the outlet pressure of the pump.
Outlet pressure = Head × Density + Inlet pressure
1# Brass Knight: Outlet pressure = Inlet pressure + Head * Density * g
5# LLH0111 – this formula is correct. The head is primarily related to the inlet pressure, as well as the back pressure from the downstream equipment, as well as the pressure losses in the pipes and those caused by other components in the pipeline such as valves, flow meters, heat exchangers, etc.
Estimation is possible, but pump manufacturers generally provide the corresponding pump performance curves, from which the head value can be determined
Outlet pressure = Head × Density + Inlet pressure
Hehe, their units are different, and their meanings are also different.
The head of a pump is the increase in pressure head provided by the pump, and this head includes dynamic head and static head. Therefore, with the outlet valve fully closed: outlet pressure = head X density + inlet pressure
Exit pressure = head × density + inlet pressure; this is incorrect from a dimensional standpoint. The unit of head is m, and the unit of density is kg/m3; their product is kg/m2. The pressure we usually refer to actually denotes stress, with the unit being Pa, that is, Newtons per m2. Therefore, the value obtained by multiplying this by the acceleration due to gravity g (with the unit of Newtons per kg) results in Newtons per m2 as well. In summary, the correct formula is Export pressure = Import pressure + Head * Density * g.