There are many kinds of formulas for calculating the head of centrifugal pump, which are based on different physical principles and calculation methods. The following are two common formulas for calculating centrifugal pump head:
1. Calculation formula based on Bernoulli equation
Centrifugal pump head (H) can be expressed in the form of the following formula:
H = h1 + h2 + Δh + h3 + h4
Among them:
H: Centrifugal pump head
h1: indicates the resistance loss of the water suction pipe
h2: Friction resistance loss in the pump body
Δh: The energy difference resulting from the density difference of the inlet and outlet fluid (in some cases, such as low-flow, low-viscosity fluids, this term can be ignored)
h3: Resistance loss of outlet pipes and valves
h4: The difference between pump outlet and liquid level height
This formula is based on the Bernoulli equation, which takes into account the energy changes of the fluid in the pump and in the pipeline to calculate the head of the centrifugal pump.
2. Calculation formula based on pressure difference and flow rate difference
Another common centrifugal pump head calculation formula is:
H = (P2 – P1) / ρg + (V2² – V1²) / 2g + h
Among them:
H: Head
P2 and P1: Pressure at the pump outlet and inlet, respectively
V2 and V1: Flow rates at the pump outlet and inlet, respectively
ρ : liquid density
g: Acceleration of gravity
h: Height difference of pump inlet and outlet
This formula calculates the head of the centrifugal pump by calculating the pressure difference at the inlet and outlet, the velocity difference and the height difference, combined with the density of the liquid and the acceleration of gravity. This method more directly reflects the work done by the pump on the liquid and the energy boost obtained by the liquid.
It should be noted that in practical applications, the head of the centrifugal pump will also be affected by a variety of factors, such as the structure of the impeller, size, speed, blade Angle, fluid viscosity, pipeline resistance, etc. Therefore, when calculating the centrifugal pump head, it is necessary to consider these factors comprehensively, and choose the appropriate calculation formula and simplified method according to the specific situation.