Velocity Pressure 4005
Velocity Pressure 4005
(OP)
I know Pv = (V/4005)^2 in English Unit.
Who can tell me how to get the 4005? I need the process of transform.
Who can tell me how to get the 4005? I need the process of transform.
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RE: Velocity Pressure 4005
V is in feet per minute.
Density of air = .075 lb/ft^3 is built in. More general formula is
V = 1097 * Sqrt(Pv/d)
where d is density.
Throw enough 12's and 60's at it and you're there.
RE: Velocity Pressure 4005
RE: Velocity Pressure 4005
Example: For a duct with a 28-by-20-in. airway, the Log-Tchebycheff method calls for a five-by-five grid
of unequally spaced measurements, while the Equal Area method requires a five-by-four grid with the distance between measurements no more than 6 in. To read more goto
http://www.hpac.com/member/archive/pdf/2001/0301/K....
pdf
RE: Velocity Pressure 4005
RE: Velocity Pressure 4005
V^2/2g (Equation 1)
Where V = Ft/sec
g = 32.1722 Ft/Sec^2
But Ft of Air = ((in. wg) x 62.3215 ) / (12 x .075) (Equation 2)
Where 62.3215 lb/ft^3 is density of water
12 = inches/ft
.075 = lb/ft^3 density of air
and in. wg. = inches of water gauge
Equate Equation 1 to Equation 2 & solve for In. wg.
and get 4005 = 60 x((2 x 32.1722 x 62.3215) / (12 x .075))^0.5
RE: Velocity Pressure 4005
RE: Velocity Pressure 4005
RE: Velocity Pressure 4005
Velocity pressure in Inches wg = (FPM velocity/4005)^2