WOBBLpropane flame
How hot does a propane flame in air get, and how much CO and NO does it make?
OK
Adiabatic flame temperature 2266 K (1992 C) for propane in air at an equivalence ratio of 1, with 1.25% CO and 0.234% NO at equilibrium.
flame temperature
2266 K
equivalence ratio
1
CO
1.25%
NO
0.234%
Confidence high
- passed element balance, energy balance, thermo data, no dissociation bound
Checks
| status | check | result |
|---|---|---|
| pass | element balance | every element of the reactants is in the products to 6e-16 |
| pass | energy balance | the products at 2266 K hold the reactants' enthalpy to 2e-09 of cp T |
| pass | thermo data | GRI-Mech 3.0's own thermodynamic data give 2266 K for the same flame, 0.0694 K from NASA's (0.0031% apart) |
| pass | no dissociation bound | burning completely to CO2 and H2O with nothing breaking apart would reach 2392 K, and dissociation takes 126 K off it |
| pass | flammability | propane burns in air from 2.1% to 9.5% by volume, an equivalence ratio of 0.51 to 2.50, and this mixture is 4.03% fuel |
Equilibrium products
| species | mole fraction |
|---|---|
| N2 | 72.08% |
| H2O | 14.85% |
| CO2 | 10.27% |
| CO | 1.25% |
| O2 | 0.5884% |
| H2 | 0.3289% |
| OH | 0.3213% |
| NO | 0.2336% |
| H | 0.04633% |
| O | 0.0311% |
Assumptions
- Propane (C3H8) and air as O2 + 3.76 N2 at 298 K and 101 kPa, fully mixed.
- Adiabatic and at constant pressure, with the products in chemical equilibrium on NASA's thermodynamic data (McBride, Gordon and Reno, NASA TM-4513). A real flame loses heat by radiation and to walls, so its peak runs below this temperature.
- Equilibrium NO is an upper bound on what a flame makes, since forming NO takes longer than most flames last.