|Distance from the orifice to the visible flame tip (L) minus the lift-off distance (s):||m|
|Release type :|
|Lift-off distance :||m|
|axial distance from the orifice (m)|
|At x :||m|
|flame diameter :||m|
The lift-off distance, s, is then determined from the following equation by Kent:
γ = isentropic exponent (heat ratio) of the actual gas = cp/cv (-) pv = upstream pressure at the event orifice (bar) po = atmospheric pressure (bar)
The effective exit velocity which is the effective exit Mach number,Mef ,times the local sound speed, is given by the following relation:
ue = exit velocity (m/s) ua = the average jet velocity (m/s) ≈ 0.4⋅ue De = the orifice or exit diameter (m)
where Tv is the upstream gas temperature and R is the individual gas constant of the actual gas which can be found by dividing the universal gas constant(=8.314 kJ/kgK) by the molecular weight of the gas.
Ct = mole ratio of fuel to reactants α = mole ratio of reactants to products (-) Tad = adiabatic flame temperature (K) Tv = temperature of the fuel before it is released (K) M0 = molecular weight of air = 29 (kmol/kg) Mf = molecular weight of fuel (kmol/kg)
where x = the axial distance from the orifice (m).