Equivalent Lengths (Le/D) for Valves and Fittings

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Discussion Overview

The discussion centers around the search for equivalent length data for valves and fittings, specifically focusing on partially closed valves. Participants are seeking references and data to aid in fluid mechanics projects.

Discussion Character

  • Exploratory, Technical explanation, Homework-related

Main Points Raised

  • One participant requests references for equivalent length data for partially closed valves, noting that existing fluid mechanics books only cover fully opened valves.
  • Another participant suggests "Crane Technical Paper 410" as a potential source, recalling that it contains relevant tables in the appendix.
  • A different participant mentions the necessity of obtaining curves from valve manufacturers, indicating that most resources, including Crane, primarily focus on fully open valves, with limited exceptions.
  • A participant expresses gratitude for the suggestions but notes that the paper reviewed did not meet their needs, considering empirical testing as an alternative approach.
  • One participant shares a link to a resource that reportedly includes equivalent lengths for partially closed valves.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on a single source for the requested data, and multiple suggestions are provided, indicating a lack of agreement on the best approach to find the information.

Contextual Notes

Some participants highlight the limitations of existing literature, particularly the focus on fully opened valves, and the potential need for empirical testing to obtain the required data.

MechanicalMan
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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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Try "Crane Technical Paper 410". My copy is at the office but I seem to remember them having some tables listed in the appendix.
 
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°.
 
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.
 
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
 
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