Local resistance coefficient of the stop valve
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This post was last edited by htcfkq on 2010-8-26 08:02. What is the local resistance coefficient when the stop valve is fully open? Are there differences between different types of stop valves?
This post was last edited by DXJ122 on 2010-8-10 at 19:50. Information can generally be found in standard chemical engineering principles and design manuals; it seems that no distinction is made between types, with globe valves being the only type mentioned. But corner valves – which can also be considered stop valves – are different. Most are expressed in equivalent length, while a few use coefficients.
There are certainly differences, and they are quite significant； Furthermore, it is highly dependent on your opening degree
According to the standard HGT 20570.7 on the calculation of pipe pressure drops, the equivalent length of common valves in terms of pipe diameter is as follows: For globe valves (fully open), when it is of type a (with the valve stem perpendicular to the fluid flow and the valve seat being flat, inclined, or plug-shaped), Le=340D； Type B: Y-shaped, Le=55D. Here, D is the inner diameter of the pipe (m).
Reply to 4# jintchinssen: Thank you, I have found the information. Why is the resistance of a Y-type stop valve so much lower?
This is likely specialized knowledge in fluid mechanics, related to factors such as changes in the direction of flow and variations in the flow state. A Y-type stop valve has a lesser impact on the flow state and direction of the fluid compared to an fully open valve; this can be seen from their respective diagrams.
With a large change in angle, the resistance is definitely going to be higher；
According to the standard HGT 20570.7 on the calculation of pipe pressure drops, the equivalent length of common valves in terms of pipe diameter is as follows: For globe valves (fully open), when it is of type a (with the valve stem perpendicular to the fluid flow and the valve seat being flat, inclined, or plug-shaped), Le=340D； Type B: Y-shaped, Le=55D. Here, D is the inner diameter of the pipe (m).
What is the local resistance coefficient of a globe valve? At full open