NPSH

[alejandro787]

hi everyone,

I have a question regarding cavitation>

There is an example on the reference All in One Civil Engineering PE, by Goswami ( example 302.7, pg 485 ) where they ask to solve for the maximum flow rate permissible. Just can't quite understand how and why to solve for flow rate in the system shown.

Anyone have this reference(Goswami) that can help me ???

Thanks .

 

[IlPadrino]

hi everyone,
I have a question regarding cavitation>

There is an example on the reference All in One Civil Engineering PE, by Goswami ( example 302.7, pg 485 ) where they ask to solve for the maximum flow rate permissible. Just can't quite understand how and why to solve for flow rate in the system shown.

Anyone have this reference(Goswami) that can help me ???

Thanks .

Please post a copy of the problem or describe it.

 

[astewart]

Just off the top of my head, doesn't NPSH just give the head capacity of a pump?

Just solve the energy equation at two points (reservoir and suction line). There will be a trade-off between elevation head, pressure head, and velocity head between the two points, plus head losses in the system. Set pressure head at the suction line equal to vapor pressure, and that corresponds with your max velocity, and therefore max Q.

I'm just blindly stumbling my way through this concept, am I right?

 

[RJs]

Couldn't understand the intended question in this thread - How to solve- I think it is shown on the example. Why? I think this is not a question. The reason to solve is to find the max Q.

As answered by astewart, the solution shown in the book is using NPSH equation to calculate the maximum Q.