What is the difference between valve flow resistance and pipeline pressure drop?
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Question: Clients often request information on the flow resistance of valves. Are there any other methods available aside from testing? Calculate? Or ANSYS simulation? What is the relationship between the flow resistance of a valve and the pressure difference before and after the valve? Should the pressure difference before and after the valve be provided by the customer? What other parameters does the customer need to provide? A beginner in this industry seeking advice
Lift it up, does anyone here know how? @lushiru @Liu Jiajia @Mr. Zhang2015 @yaoshuyan
The flow resistance and pressure drop of a valve are not the same concept, but they are related. Flow resistance generally refers to the flow resistance coefficient of a valve; it is related to the structure of the flow channels, as well as the degree of opening of the valve and the flow velocity of the medium, and it is a value that changes. Generally speaking, for a valve with a fixed structure, at a certain degree of opening, there is a fixed flow coefficient. Depending on the flow rate, the pressure difference across the valve’s inlet and outlet can be calculated, and this pressure difference is what is known as pressure loss.
What customers generally need to know is the pressure loss, that is, the pressure difference between the inlet and outlet of the valve. For conventional valves, customers usually need to specify the flow rate; we can provide the pressure difference at full open condition ； For control valves, we can provide a flow-pressure difference curve.
The guy on the fourth floor gave extremely comprehensive and insightful answers； If you want to know the details, you can search for posts on the methods for calculating valve pressure to learn about it*~