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Valves with Intercept
Posted: Tue Jul 28, 2009 7:25 am
by Irrigator
Hi everybody.
I don’t know the meaning of “valves with intercept” (Headloss equation Intercept (C) Who could help me?
Thanks a lot. Irrigator
Re: Valves with Intercept
Posted: Wed Jul 29, 2009 1:16 pm
by Dan Crosby
Hi Irrigator,
The headloss equation for valves is in the form:
- H = KQn + C
- H = headloss
- Q = flow
- K = constant
- n = index
- C = intercept
The intercept C represents any headloss in the valve assembly that is not dependent on the flow through the valve. It can be used to introduce a fixed amount of headloss through the valve, but typically there is no flow-independent component to the headloss, and C is zero. However, if you are trying to produce a headloss equation from experimental data, you may find that the curve fits better if an intercept is used. In practice this should not be a problem, provided the valve is only used in flow regimes that are 'on the curve'.
Re: Valves with Intercept
Posted: Wed Jul 29, 2009 1:43 pm
by jovivier
The intercept can represent a start-up head required, eg if a valve requires a certain upstream pressure before it will open and the curve cuts the Y-axis instead of going through 0,0.
Re: Valves with Intercept
Posted: Wed Jul 29, 2009 10:47 pm
by Irrigator
Fine Dan. Thanks a lot.
Irrigator
Dan Crosby wrote:Hi Irrigator,
The headloss equation for valves is in the form:
- H = KQn + C
- H = headloss
- Q = flow
- K = constant
- n = index
- C = intercept
The intercept C represents any headloss in the valve assembly that is not dependent on the flow through the valve. It can be used to introduce a fixed amount of headloss through the valve, but typically there is no flow-independent component to the headloss, and C is zero. However, if you are trying to produce a headloss equation from experimental data, you may find that the curve fits better if an intercept is used. In practice this should not be a problem, provided the valve is only used in flow regimes that are 'on the curve'.