Questions about the Barb factor (Kd)

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marcioagr
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Company: Fazendas Reunidas Laia & Souza
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Questions about the Barb factor (Kd)

Post by marcioagr »

Hi!
When editing tapes for calculating load loss there is a factor (Kd) and in this case the value varies from 0 to 2, however some suppliers do not provide this value in the catalogs.
I would like to know if there is an impirical formula to estimate the barb factor (Kd) or when you don't know this value you could use the value 1 for example!
If using zero or 2, what would be the influence on the pressure calculation in the project?
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jovivier
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Re: Questions about the Barb factor (Kd)

Post by jovivier »

Hi Marcio,

The emitter barb factor (Kd) is used to calculate the headloss past the emitter and uses the formula H = Kd V² / 2g.

The easiest way to determine the emitter barb factor is a manual iteration process:-
- draw out several tapes (e.g., 100m , 200m, 300m)
- connect them to a large pipe and control valve
- Analyze
- change the emitter barb factor in the database until the expected headloss is achieved.

The IRRICAD Team
marcioagr
Posts: 49
Joined: Sun Aug 23, 2020 7:07 am
Company: Fazendas Reunidas Laia & Souza
City / Town: INHAPIM
Product: Irricad Standalone

Re: Questions about the Barb factor (Kd)

Post by marcioagr »

OK!
I found a thesis here in Brazil where they arrived at an equation to estimate Kd.
I will exercise in the field and also do as you said.

https://www.scielo.br/scielo.php?script ... 9000100004
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Mario Dominguez
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Re: Questions about the Barb factor (Kd)

Post by Mario Dominguez »

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