Hi, i'm currently having problem in sizing of a aircraft fuel pump. The fuel consumption of the aircraft is (18gal/hr). What size of tube should be use 1/2 inch or 3/8 inch inorder to meet the requirement. Please advice.
For pressurized fuel systems, flow reynolds numbers must remain below 5000 and velocities under 1.35 fps.
Fuel pressure losses in round tubing at low vapor-liquid ratios may be computed by the following relationship:
delta P = 3.417 x 10(-5) x u(0.25)l P(0.75)v(1.75)/d(1.25)
all X (1-V/L)
Where: u = viscosity, English units (centipoise x 0.000672)
l = Length of pipe, ft.
p = Density of fluid (lbs/cu ft)
v = Mean velocity of fluid, fps
d = Inside diameter of pipe, ft.
V/L = Vapor liquid ratio, dimensionless
delta P = Pressure drop, psi
Note: Numbers in parenthesis are powers i.e. 10(-5) = ten to the minus five power.
I forgot to preface my remarks to indicate that the reynolds number and velocity are recommended design practice for general aviation piston aircraft fuel systems.