What Is the Zeldovich Thermal NOx Formation Rate Calculator?
The Zeldovich mechanism describes thermal NO formation through three elementary reactions: O + N2 ⇄ NO + N, N + O2 ⇄ NO + O, and N + OH ⇄ NO + H.
The initial breaking of the strong N≡N triple bond requires 319 kJ/mol, causing the rate to soar above 1800 K.
How Does the Zeldovich Thermal NOx Formation Rate Calculator Work?
Thermal NO formation rate is proportional to P^0.5, [O2]^0.5, [N2], and exp(-Ea/RT).
Because of this exponential dependence, reducing peak flame temperature by only 50 K can cut thermal NOx in half.
Zeldovich Thermal NOx Formation Rate Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Rate-limiting O + N2 -> NO + N reaction with high activation energy (319 kJ/mol).
How to Use the Zeldovich Thermal NOx Formation Rate Calculator
- Input flame temperature, combustor pressure, O2/N2 fractions, and residence time.
- Inspect the formation rate in ppm/ms and total emitted NOx in ppmvd.
Step-by-Step Example Calculation
Gas Turbine Combustor Hot Section
Input Values:
Understanding Your Result
Dry low NOx (DLN) lean-premixed combustors target flame temperatures below 1800 K to suppress thermal NOx below 9–15 ppm.
Factors That Affect the Result
- Higher combustor pressure and longer residence time linearly or root-square increase emissions.
- Steam or water injection cools flame temperatures to curb thermal NOx.
When Should You Use This Calculator?
- Gas turbine combustor design, industrial burner emission modeling, and EPA compliance engineering.
Assumptions & Limitations
- Focuses on thermal NOx; prompt NOx (Fenimore) and fuel-bound NOx are not included in this model.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard chemical kinetics formulation based on GRI-Mech and NIST rate data.