Parallel pump operations-power failure

[unitradingco]

we are planning to run two identical centrifugal pumps in parallel. one is motor driver, the other is steam turbine driver.
During normal opertions, a power failure occured, how fast can the turbine pump speed up to make up with the loss flow? lets say from 1700 RPM to 1750 RPM, one, two, five minutes ??

 

[desertfox]

Hi unitradingo

The way to solve your problem is to use the "angular impulse"= "change in angular momentum" in order to do this you would need to know the "moment of inertia" of the turbine and the change in the torque applied to the turbine
after the power failure.
The equation then :-


Txt=I x (w1-w0)

where T=the change in torque in your case
I=moment of inertia of turbine
w1,w0= the final and initial angular velocities of the
turbine which you can calculate from the r.p.m
you have posted.
t= time required to reach final angular velocity

so transposing the formula to give t

t=I x (w1-w0)/(T)

note there are no losses for friction etc within the above formula.

hope this helps

 

[unitradingco]

Thanks, desertfox.