Regarding the calculation of the flow coefficient of control valves
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To calculate the flow coefficient of a control valve, many parameters are required, such as FL, FF, as well as PV and PC. PV represents the saturated vapor pressure of the liquid; relevant physical and chemical data must be consulted to obtain this value. Where can such data be found for alkaline solutions?
Why isn’t anyone answering? The software can do the calculations, but there are many things I don’t understand I hope an expert can provide an answer; thank you
My understanding is that when calculating the flow coefficient of a control valve, it seems that the main process parameters such as the pressure difference before and after the valve as well as the flow rate are required; as for values like FL, manufacturers’ calculation software typically combines them into a single compensation parameter for use in the calculations. I hope everyone can point out any mistakes
That is, we do the same here too! It can be calculated as long as some parameters are known; if you want to do it by hand, you can use tables! There should be some tables; as for what exactly they are, I’m not quite sure
Generally, it is necessary to know parameters such as the inlet pressure, temperature, flow rate, and outlet pressure of the valve. These parameters are automatically entered into the selection software, which then allows for the calculation to be carried out. If one were to calculate it manually, for a non-obstructed flow, Kv = 10Q*sqrt(ρ/p1-p2), where Q represents the flow rate, sqrt denotes the square root function, ρ represents the density, and p1-p2 represents the difference between the absolute inlet pressure and the absolute outlet pressure of the valve.
When calculating the CV value of a valve, several different scenarios need to be considered; the calculation is based on the properties of the fluid, such as whether it is a liquid, a gas, or a two-phase flow of gas and liquid. The specific calculations are provided in the formula for calculating flow rate.
Indeed, these days it’s rare to do the calculations by hand; everyone uses software for that, which can be downloaded from the internet. :)
The saturated vapor pressure of liquids for common pure substances can generally be found in tables of physical and chemical properties, whereas the saturated vapor pressure of mixed (non-ideal) substances is calculated using formulas
Where can I download the physical and chemical data sheet?