Calculating hydrogen gas discharge flow from a pipe opening
Calculating hydrogen gas discharge flow from a pipe opening
(OP)
I trying to find a quick way to calculate the actual flow rate of hydrogen gas at the discharge point of a 1/8" (0.3175cm) pipe, if the pressure drop is from 74.7psi (515Pa) to 14.7psi (101.4Pa ambient air pressure). The compressed hydrogen gas is at normal room temperature.
RE: Calculating hydrogen gas discharge flow from a pipe opening
Matt
RE: Calculating hydrogen gas discharge flow from a pipe opening
The pipe is 10cm long. I am not sure what you mean with converting all the pressure to velocity.
RE: Calculating hydrogen gas discharge flow from a pipe opening
Base on critical velocity (which you don't want to pass)
The max flow is ~3lb/hr
BTW most of the pressure drop is probably at your valve.
RE: Calculating hydrogen gas discharge flow from a pipe opening
Doesn't temperature AND pressure play a role if you go from a compresed gas @ 60 psi (gauge) to atmospheric pressure?
RE: Calculating hydrogen gas discharge flow from a pipe opening
RE: Calculating hydrogen gas discharge flow from a pipe opening
RE: Calculating hydrogen gas discharge flow from a pipe opening
M=C*A*{k*ρ*P(2/k+1)^[(k+1)/(k-1)]}^0.5
K(H2)=1.410
Minimum P/Pd required for H2 choked flow = 1.899
M= mass flow rate, kg/s
C = discharge coefficient, dimensionless (~0.62)
A = discharge hole cross-sectional area, m²
k = cp/cv of the gas
cp = specific heat of the gas at constant pressure
cv = specific heat of the gas at constant volume
ρ = real gas density at P and T, kg/m³
P = absolute upstream pressure of the gas, Pa
Pd = absolute downstream gas pressure
good luck