The combustion temperature calculator estimates the adiabatic flame temperature achieved during a combustion process. This calculation is crucial in optimizing combustion efficiency, minimizing pollutant formation, and improving fuel utilization. It helps engineers and scientists determine the maximum temperature based on fuel properties, reactant conditions, and specific combustion products.
Formula of Combustion Temperature Calculator
The adiabatic combustion temperature formula is:
T_combustion = T_initial + (ΔH_combustion / Σ(n_i * c_p,i))
Where:
- T_combustion is the adiabatic combustion temperature (in kelvins, K).
- T_initial is the initial temperature of the reactants (in kelvins, K).
- ΔH_combustion is the heat of combustion (in joules or kilojoules per mole of fuel).
- n_i is the number of moles of each product species.
- c_p,i is the specific heat capacity of each product species (in joules per mole per kelvin, J/(mol·K)).
Dependent Variable Formulas
- Heat of Combustion
ΔH_combustion = Σ(ΔHf_reactants) – Σ(ΔHf_products)
Where:- ΔHf_reactants is the enthalpy of formation of reactants.
- ΔHf_products is the enthalpy of formation of products.
- Total Heat Capacity of Products
Σ(n_i * c_p,i) = n_CO2 * c_p,CO2 + n_H2O * c_p,H2O + n_N2 * c_p,N2 + …
Where:- n_CO2, n_H2O, n_N2, etc., are the moles of combustion products.
- c_p,CO2, c_p,H2O, c_p,N2, etc., are the specific heat capacities of the products.
- Initial Temperature of Reactants
T_initial = T_ambient + ΔT_preheat
Where:- T_ambient is the ambient temperature.
- ΔT_preheat is the temperature increase from preheating reactants.
Combined Formula
T_combustion = T_initial + (Σ(ΔHf_reactants – ΔHf_products) / Σ(n_i * c_p,i))
Useful Conversion Table
| Parameter | Unit | Typical Values/Notes |
|---|---|---|
| Heat of Combustion (ΔH_combustion) | kJ/mol or MJ/kg | Depends on the fuel, ~50 MJ/kg for methane |
| Specific Heat (c_p,i) | J/(mol·K) or BTU/(lb·°F) | 37 J/(mol·K) for CO₂, 33 J/(mol·K) for H₂O |
| Ambient Temperature (T_ambient) | K or °C | Typical range: 298 K (25°C) |
| Preheat Temperature Increase (ΔT_preheat) | K | Varies, typically 100–200 K |
| Moles of Products (n_i) | Dimensionless | Based on stoichiometric combustion equations |
Example of Combustion Temperature Calculator
A methane combustion system burns 1 mole of CH₄ in the presence of 2 moles of O₂. The reactants are at an initial temperature (T_initial) of 298 K, and the preheating adds 150 K. The products include CO₂ and H₂O, with specific heat capacities of 37 J/(mol·K) and 33 J/(mol·K), respectively. The heat of combustion for methane is 890 kJ/mol.
- Calculate total heat capacity of products: Σ(n_i * c_p,i) = (1 * 37 J/(mol·K)) + (2 * 33 J/(mol·K)) = 103 J/(mol·K)
- Calculate ΔH_combustion: ΔH_combustion = 890,000 J/mol
- Compute adiabatic combustion temperature: T_combustion = T_initial + (ΔH_combustion / Σ(n_i * c_p,i)) T_combustion = 298 K + 150 K + (890,000 J / 103 J/K) T_combustion = 298 K + 150 K + 8,640 K = 9,088 K.
The calculated adiabatic combustion temperature is approximately 9,088 K.
Most Common FAQs
Adiabatic combustion temperature is the theoretical maximum temperature a combustion system can achieve without any heat loss to the surroundings.
Calculating combustion temperature helps in designing combustion systems, optimizing fuel efficiency, and reducing harmful emissions.
No, adiabatic combustion temperature represents the upper theoretical limit. Real-world temperatures are lower due to heat losses and inefficiencies.