Stochastic simulation of hydrogen-oxygen auto-ignition at the microscale
1Wide Range Flight Engineering Science and Applications Centers, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
The Journal of Chemical Physics
|August 22, 2023
Summary
Stochastic simulations reveal that molecule number significantly impacts hydrogen-oxygen auto-ignition delay times at the microscale. Lower molecule counts amplify stochastic effects, especially near the crossover temperature.
Area of Science:
- Chemical Engineering
- Combustion Science
- Computational Chemistry
Background:
- Microscale H2-O2 auto-ignition is crucial for many applications.
- Stochastic effects in chemical kinetics become significant at low molecule numbers.
Purpose of the Study:
- To investigate the impact of stochasticity on H2-O2 auto-ignition at the microscale.
- To analyze the statistical properties of ignition delay time under varying conditions.
Main Methods:
- A hybrid stochastic simulation method was developed.
- Ignition delay time was analyzed for different initial temperatures and total molecular numbers.
Main Results:
- Discrete reaction collision characteristics notably affect early ignition stages.
- Ignition delay time's average and standard deviation increase with decreasing molecular number.
- The crossover temperature region exhibits the strongest relative fluctuation.
- A theoretical equation for standard deviation showed excellent agreement with simulations.
Conclusions:
- Stochasticity plays a critical role in microscale H2-O2 auto-ignition.
- Molecular number and temperature significantly influence ignition delay time statistics.
- The developed theoretical equation accurately predicts ignition delay time standard deviation.
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