Mixed Gas Formula (Drainage)
Volume flow of drained mixed gas through an orifice plate — coal-mine gas drainage practice.
Formula
QH = K·b·√ΔH·бT·бP / √9.81
QHFlow QH
KOrifice coefficient K (calibrated value)
b = √(1/(1−0.00446X))Concentration correction b
бT = √(293/(273+t))Temperature correction бT
бP = √(PT/101.325)Pressure correction бP
PT = PD ± PGAbsolute pressure before orifice PT
1 atm = 101.325 kPa; 1 mmH2O = 9.80665 Pa; 1 mmHg = 0.133322 kPa
Inputs
%
mmH2O
°C
mmHg
kPa