Dear Engineers:
I have a control valve that reduce discharge pressure of a multistage pump from 55.9 bara to 0.25 bara.
The valve acting as minimum flow for pump. But sometimes this valve needs to be dismantled and the minimum flow to be controlled with a by pass which is a simple globe valve. Because of this high delta P, adjustment of flow by globe valve is not possible.
I decided to use a restriction orifice after the globe valve on bypass line, but after calculation by spnkflo program, it says the velocity is very high and I should use a multihole orifice. I didn't bring the delta P over the globe in the calculation. My beta ratio is too low too. So what can I do instead of this orifice? Or how I can decrease the pressure?
Here is the data of my calculation:
Fluid: liquid
T = 56 C ID = 76.2 mm Density = 851 kg/m3 viscosity = 0.668 cp
dp over orifice = 55.65 bar normal flow = 1.044 kg/s
result: d = 4.7435 mm,v = 68.48m/s
I hope someone could help.