A numerical study of spatial structure during oscillatory combustion in closed vessels in microgravity

Area of Science:

• Chemical kinetics
• Physical chemistry
• Computational fluid dynamics

Background:

• Investigates thermokinetic oscillations under microgravity conditions, inspired by butane oxidation experiments.
• Utilizes the Sal'nikov thermokinetic scheme (P-->A-->B) as a two-variable model for oscillatory reactions.

Purpose of the Study:

• To numerically investigate the existence and spatial development of gas-phase, thermokinetic oscillations under microgravity.
• To study the influence of mass and thermal diffusion on oscillatory reaction behavior.
• To compare two numerical simulation approaches for supplying the precursor reactant.

Main Methods:

• Numerical investigation of a 1-dimensional system using the Sal'nikov thermokinetic scheme.
• Simulation of gas-phase reactions under conditions mimicking microgravity.
• Two methods for precursor supply: simultaneous throughout the system and at the inner boundary.

Main Results:

• Demonstrates the existence and spatial development of thermokinetic oscillations driven solely by diffusion.
• Shows that oscillatory states can be sustained by heat and mass transport.
• Analyzes the temporal and spatial evolution of reactions under various diffusion-driven conditions.

Conclusions:

• Thermokinetic oscillations can be sustained in a diffusion-dominated system under microgravity.
• Numerical simulations provide insights into oscillatory reaction dynamics relevant to space experiments.
• The study highlights the importance of diffusion in enabling oscillatory behavior in the absence of convection.