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# Resistance Factor Calculation For Eccentric Reducers And Expanders

6 replies to this topic
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### #1 pxyarala

pxyarala

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Posted 26 August 2020 - 02:43 PM

Dear Colleagues,

I need to calculate the Resistance factor for Eccentric Reducers and Expanders to determine its equivalent for use in Pump Sizing calculation. I have got the methodology for Concentric Reducers and Expanders from one of the posts by Mr. Ankur Shrivatsava. I was wondering if the same equations can used  by replacing the convergence or divergence angle for Concentric reducers/expanders with that for Eccentric Reducers/ Expanders. If I cannot find any information I was planning on taking 30% margin over the K factor calculated for concentric reducers or expanders and use it for Eccentric Reducers / Expanders.  Please post if any information is available.

Thanks and Regards,

Pavan Kumar

### #2 breizh

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Posted 26 August 2020 - 06:30 PM

Hi,

Let you try to get a copy of the book in reference :

Breizh

For eccentric:

Pipe flow : A practical and comprehensive guide Donald C,Rennels &  Hobart M.Hudson

K2 = 0.0696*(1-β^5)*λ^2+(λ-1)^2           with λ=1+0.622*(1-0.215*β^2-0.785*β^5)

β= D2(ID)/D1(ID)

(ID) : internal diameter

Edited by breizh, 26 August 2020 - 06:31 PM.

### #3 Chemitofreak

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Posted 27 August 2020 - 04:44 AM

You can refer the Crane Fluid Flow Handbook, the bible for fluid flow

### #4 latexman

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Posted 27 August 2020 - 06:30 AM

For most commercial reducers, I use K1 = 0.1 (based on velocity in smaller pipe).  It works quite well when the contraction is 1 (smaller piping) to 3 (larger  piping) nominal pipe sizes different.

If you had described, attached, or linked to the methodology for Concentric Reducers and Expanders from Mr. Ankur Shrivatsava we could answer your questions, but you did not.

Edited by latexman, 27 August 2020 - 08:42 AM.

### #5 pxyarala

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Posted 27 August 2020 - 10:20 AM

Hi All,

Sorry I forgot to paste the link that referred to Mr. Ankur Shrivatsava's post earlier. I have pasted it here below now.

https://www.cheresou...her-than-steel/

Thanks and Regards,

Pavan Kumar

### #6 pxyarala

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Posted 27 August 2020 - 10:28 AM

Hi breizh,

The formula for K2 for eccentric doesnot include the reducer angle Alpha that is included for Concentric reducers?. Would it be possible for you to share the snap shot from the book for Eccentric reducers and expanders?.

Attached please find the spreadsheet please look for the Tab "K_for_Conc_Reducers_Expanders" for the snapshots from the book that you mentioned for Concentric reducers.

Thanks and Regards,

Pavan Kumar

### #7 pxyarala

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Posted 27 August 2020 - 10:34 AM

Hi Chemitofreak,

I normally use the equations from Crane TP410 which is good for my calculations. However the reference from the book "Pipe Flow - A Practical and Comprehensive Guide" by Donald C Rennels and Hobart M. Hudson seemed to provide the basis for the formulae, while Crane TP410 does not provide the basis for the calculations. There is no formula for Eccentric reducers / expanders in Crane TP 410.

Thanks and Regards,

Pavan Kumar