Liquid Dynamics International Ltd. - Piping System Analysis / Piping System Simulation

LDi – P46

Check the amplitude of any highly excitational pressure spikes
In pump literature a.k.a. "Velocity Jump" causing "Joukowsky shock"

Example: Actual results depend on stroke radius to connecting mechanism length, etc.
Flow Velocity for crank shaft angle
180 degrees of pump rotation
The velocity to which the liquid has to leap from being static in zero time
3.2 x rated flow @ 50% volumetric efficiency
2.6 x rated flow @ 64% volumetric efficiency
2.175 x rated flow @ 77.5% volumetric efficiency
1.6 x rated flow @ 87% volumetric efficiency
0.7 x rated flow @ 96.68% volumetric efficiency

Pressure
Time – 180 degrees of pump rotation
Velocity Jump Shock
Acceleration Head
How system pressure reacts
Follow the red to green boundary
Theoretical steady state pipeline pressure
Valve bounce

You can reduce "Velocity Jump Shock" to a generally insignificant figure in 4 simple steps:
1. Select a damper with an ID 12 times the diameter of the inlet connection.
2. Have an outlet 1/2 the area of the inlet.
3. Increase the volume by 3 times the inefficiency.
4. Decrease the cushion pre-fill pressure proportionately to the volume increase, from 80% of system pressure to as low as 50%.

The combined effect of mass acceleration, velocity jump, pressure wave acoustics, fittings and pipe resistance all in a time dependent frame, along with valve action, and pump characteristics may be modeled for you by: LDi PulseView software. This is not a free service. Please complete input data set tabulation.