Questions about the Barb factor (Kd)

marcioagr · Post by **marcioagr** » Mon Oct 19, 2020 6:55 am

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?

Post by **jovivier** » Thu Oct 22, 2020 1:21 pm

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 · Post by **marcioagr** » Fri Oct 23, 2020 5:48 am

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

Mario Dominguez · Post by **Mario Dominguez** » Fri Jul 29, 2022 3:36 am

photo_2022-07-28_10-35-44.jpg

jabesmedeiros · Post by **jabesmedeiros** » Fri Oct 20, 2023 2:49 am

Gracias a todos por el aporte respecto a los valores de Kd.

Saludos.

Jabes Medeiros.

Irricad

Questions about the Barb factor (Kd)

Questions about the Barb factor (Kd)

Re: Questions about the Barb factor (Kd)

Re: Questions about the Barb factor (Kd)

Re: Questions about the Barb factor (Kd)

Re: Questions about the Barb factor (Kd)