pressure of water in a line and head relationship

[santu398]

Hello everyone,

I have to select a pump giving Q flow and maintaining P line pressure. How to calculate the head required for the pump. The pump rated head minus TDH responsible for line pressure?

I have below questions. Please help

What will be the line pressure P at the delivery of a centrifugal pump (delivering Q)running at a system head which is equal to the rated pump head (BEP)?

If the delivery is throttled to Q/2, we can find the head from pump curve corresponding to the flow rate. With this head, how to calculate line pressure?

Will this work here.

P = density X g X head.

 

[Softedge]

santu398
you provide very little information on your system and what you are pumping.

basically, the pump will react to the system conditions. for your required flow rate and system configuration use bernoulli's equation to calculate the total head on the discharge side of the pump and the total head on the inlet side of the pump. add the two together to obtain the energy the pump will have to add to the system to achieve the required flow rate. once you have the head and flow rate, go to the pump curve to determine the operating parameters for the pump.

regards,
softedge

 

[bimr]

An efficient and simple method to calculate the pressure loss in a piping system is the "Equivalent Pipe Length Method".

http://www.engineeringtoolbox.com/equivalent-pipe-length-method-d_804.html

Another method is the Crane method:

https://neutrium.net/fluid_flow/pressure-loss-from-fittings-excess-head-k-method/

In United States Customary System Units, p = rho * H,

where p = pressure, psf

rho= weight-density of 62.4 lbs/square foot

H = feet

http://www.mcnallyinstitute.com/07-html/7-01.html

In metric units:

Hydrostatic pressure is the pressure due to the weight of a fluid.

p=rho*g*h

where:

ρ (rho) is density of the fluid (eg water density is almost 1000 kg/m3);

g is the acceleration due to gravity (conventional, 9.80665 m/s2 to the sea surface);

h is the height of column of liquid (in meters).

 

[chicopee]

If you do a search of pump characteristic curves vs. system performance curves in this forum, you'll get answers to your questions since much on this subject has been discussed.