Page 216 - Parker - Polyflex Hose Products (Ultra High Pressure Thermoplastic Hose)
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polyflex ®
Catalog 4900
Technical Information Selection of Hose Diameter
Determination of Pressure Drop in the Line
Q W q
Velocity: v = .409 = .0509 =
d 2 pd 2 .785d 2
dvp W qp
Reynold’s Number: Re = 124 µ = 6.31 dµ = 378 dµ
Pressure Drop, Isothermal, Incompressible Flow (Liquids):
2 2 2
fL p v fLW fL q
∆ ∆ ∆ ∆ ∆P = .001 294 = .000 00336 = .0121
d pd 5 d 5
Pressure Drop, Isothermal, Compressible, Long Lines (Gases and Vapors):
v 2
∆ ∆ ∆ ∆ ∆P = 1 – 1 – fLp 1 1
P1 √ 12 g d P 1
Symbols and Units for Listed Formulas
d = inside diameter of hose, inches
F
f = friction coefficient, dimensionless
g = gravitational constant, 32.2 ft./sec. 2
P1 = input pressure, psi
∆ ∆ ∆ ∆ ∆P = pressure difference, psi
q = rate of flow at flowing condition, cu. ft./min.
Q = rate of flow, gals./min.
Re = Reynolds number, dimensionless
v = flow velocity, ft./sec.
W = rate of flow, lbs./hr.
p = weight density of fluid, lbs./cu. ft.
µ = absolute (dynamic) viscosity, centipoises
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