Orifice Pressure and Flow drop

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0http://math.stackexchange.com/questions/946493/solve-for-pressure-drop-across-and-orifice# [Broken]
I'm running 1/2" pipe but the only way to connect a 9/16" flow switch is with a 1/4" adapter. I'd have to go from 1/2" down to 1/4" to the 9/16" flow switch down to 1/4" back to 1/2".

I was wondering if this would cause a large pressure drop but I used this online calculator and was wondering if anyone could verify these numbers:

Calculation output

Flow medium: Water 20 °C / liquid

Volume flow: 2 l/min

Weight density: 998.206 kg/m³

Dynamic Viscosity: 1001.61 10-6 kg/ms

Element of pipe: Orifice sharp-edged

Dimensions of element: Diameter of pipe D1: .5 in.

Diameter of pipe D2: .25 in.

Velocity of flow: 0.86 ft./s

Reynolds number: 3330

Velocity of flow 2: 3.45 ft./s

Reynolds number 2: 6661

Flow: turbulent

Absolute roughness:

Pipe friction number:

Resistance coefficient: 30.68

Resist.coeff.branching pipe: -

Press.drop branch.pipe: -

Pressure drop: 22.14 lbw./sq.ft.

0.15 psi

I've also looked at a flow rate calculator and was wondering if the down size in the piping would affect the flow rate substantially? I'm really trying to stay at 2L/min.
 
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Answers and Replies

47
5
0http://math.stackexchange.com/questions/946493/solve-for-pressure-drop-across-and-orifice# [Broken]
I'm running 1/2" pipe but the only way to connect a 9/16" flow switch is with a 1/4" adapter. I'd have to go from 1/2" down to 1/4" to the 9/16" flow switch down to 1/4" back to 1/2".

I was wondering if this would cause a large pressure drop but I used this online calculator and was wondering if anyone could verify these numbers:

Calculation output

Flow medium: Water 20 °C / liquid

Volume flow: 2 l/min

Weight density: 998.206 kg/m³

Dynamic Viscosity: 1001.61 10-6 kg/ms

Element of pipe: Orifice sharp-edged

Dimensions of element: Diameter of pipe D1: .5 in.

Diameter of pipe D2: .25 in.

Velocity of flow: 0.86 ft./s

Reynolds number: 3330

Velocity of flow 2: 3.45 ft./s

Reynolds number 2: 6661

Flow: turbulent

Absolute roughness:

Pipe friction number:

Resistance coefficient: 30.68

Resist.coeff.branching pipe: -

Press.drop branch.pipe: -

Pressure drop: 22.14 lbw./sq.ft.

0.15 psi

I've also looked at a flow rate calculator and was wondering if the down size in the piping would affect the flow rate substantially? I'm really trying to stay at 2L/min.
Head Loss due to sudden contraction or sudden expansion in area of flow is given by the formula,
hL = (Vs2/2g)×{1-(As/Al)}2
where the subscripts 's' and 'l' denote the flow properties at the smaller area region and the larger area region respectively.
Substitute the values in this equation and you can determine how much extra pressure difference needs to be created to maintain the same flow as the case when there was no variation in area of flow.
 
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