Combustion chamber

Air and flue-gas flows, excess air from a measured O2, the adiabatic flame temperature by chemical equilibrium, the flue-gas dew point and the loading of the chamber — for natural gas, LPG, hydrogen blends, oils and solid fuels.

FREE · NO SIGN-UP v1.0.0 · verified against 6 reference cases

INPUT1.013 bar · Nm³ at 0 °C

1 · Fuel

Start from

Firing rate [kW] on the lower heating value

2 · Air

Set by Excess air [%]

Air temperature [°C] after any preheater Relative humidity [%]

3 · Chamber

Inside diameter [m] Length [m]

4 · Walls and stack Pro+

Wall temperature [°C] water-cooled: near the water's Wall emissivity

Flue gas at the stack [°C]

Example values, not a real plant. The diesel and heavy fuel oil analyses are those published by Natural Resources Canada for its boiler stack-loss method.

ADIABATIC FLAME T1823 °C

FURNACE · LIVE

FLAME T AGAINST EXCESS AIRequilibrium

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HOW IT'S CALCULATED · WITH YOUR NUMBERS

Step by step, with your numbers

01
Equilibrium████ ██ ███████ · ██████ = ██.██
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Reactions████ ██ ███████ · ██████ = ██.██
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Shear force████ ██ ███████ · ██████ = ██.██
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Bending moment████ ██ ███████ · ██████ = ██.██
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Deflection████ ██ ███████ · ██████ = ██.██
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Stress████ ██ ███████ · ██████ = ██.██

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References: chemical equilibrium by Gibbs minimisation with NASA polynomials (GRI-Mech 3.0), checked against Cantera; IAPWS-IF97 saturation line; Natural Resources Canada boiler stack-loss method; Smith, Shen & Friedman (1982) weighted-sum-of-grey-gases emissivity.

ASSUMPTIONS & LIMITS

Atmospheric pressure (1.01325 bar). Dry air 78.084 % N2, 20.946 % O2, 0.934 % Ar, 0.036 % CO2, plus the water vapour of the relative humidity. Normal cubic metres at 0 °C and 1.01325 bar.
The flue-gas composition, flows and dew point are for complete combustion. The adiabatic flame temperature is for chemical equilibrium (dissociation included), fuel at 25 °C, no heat lost.
Thermodynamic data: NASA polynomials of GRI-Mech 3.0 and the NASA database. Liquid and solid fuels are defined by their ultimate analysis and heating value; their enthalpy follows from the HHV.
No emissions are predicted: NO, CO and soot depend on the burner and the flow, which only a reacting CFD model resolves.
Furnace model (Pro+): one well-stirred zone at the exit temperature, grey gas, no soot or particle radiation, no convection. It is an energy balance, not a flame model.

DISCLAIMER · For education and preliminary sizing only. Results must be reviewed by a qualified engineer before use in design.

BEYOND THE ENERGY BALANCE

Flame shape, hot spots on the furnace wall, NOx and CO, burner retrofits and hydrogen blending — we model the flame with reacting CFD.

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