Equivalent Lengths (Le/D) for Valves and Fittings

In summary, the conversation discusses the need for data on partially closed valves and fittings, as most fluid mechanics books only provide data for fully open valves. A recommendation is given to try the "Crane Technical Paper 410" for tables in the appendix, but it may be necessary to obtain curves from the manufacturer. The conversation also mentions an exception for a tilting disc check valve and a link to a website with equivalent lengths for partially closed valves. Ultimately, conducting tests may be necessary to obtain accurate data.
  • #1
MechanicalMan
25
0
Can anyone recommend any good references for equivalent length data for valves and fittings? All of my fluid mechanics books only have data for fully opened vales, but I'm currently working on a project where I need to know the values for partially closed valves.

I tried to do a Google search but came up with nothing relevant. Thanks in advance.
 
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  • #2
Try "Crane Technical Paper 410". My copy is at the office but I seem to remember them having some tables listed in the appendix.
 
  • #3
For information like that, you'll need to get curves from the manufacturer of the valves. I can't remember any off the top of my head that listed partially open flows. Even Crane makes the distinction of fully open on most valves in its section of resistance coefficients. There is one exception in which they list a tilting disc check valve opening of 5° and 15°.
 
  • #4
Thanks for your responses.

I looked into the paper today, but it wasn't exactly what I needed. I may just need to do some tests and try to solve for it empirically.
 
  • #5
I just happened to run across this today...it shows so equivalent lengths for partially closed valves.

http://www.constructionwork.com/resources_details_1474friction_of_fittings.html [Broken]
 
Last edited by a moderator:

What is the significance of Equivalent Lengths (Le/D) for Valves and Fittings?

Equivalent Lengths (Le/D) for valves and fittings are used in fluid flow calculations to account for the pressure drop caused by the presence of these elements in a piping system. It represents the length of straight pipe that would cause the same pressure drop as the valve or fitting.

How is Equivalent Length (Le/D) calculated for valves and fittings?

The Equivalent Length (Le/D) is typically calculated using empirical data from experiments or by using published tables that provide values for different types of valves and fittings. These values are then multiplied by the pipe diameter (D) to obtain the final Equivalent Length value.

What factors affect the Equivalent Length (Le/D) for valves and fittings?

The Equivalent Length (Le/D) for valves and fittings is affected by several factors such as the type and size of the valve or fitting, the Reynolds number of the fluid, and the angle of the valve or fitting in the piping system. It is important to use the correct Equivalent Length value based on these factors to ensure accurate fluid flow calculations.

Why is it important to consider Equivalent Length (Le/D) in fluid flow calculations?

Valves and fittings in a piping system can cause significant pressure drops, which can affect the overall efficiency of the system. By using Equivalent Length (Le/D) values, these pressure drops can be accounted for and accurate fluid flow calculations can be performed to ensure optimal system design and operation.

Can the Equivalent Length (Le/D) for valves and fittings change over time?

The Equivalent Length (Le/D) for valves and fittings can change over time due to factors such as wear and tear, corrosion, and changes in the fluid properties. It is important to regularly monitor and update these values to ensure accurate fluid flow calculations and maintain the efficiency of the piping system.

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