Kinetic effects in thermal explosion with oscillating ambient conditions

Area of Science:

• Chemical Engineering
• Thermodynamics
• Reaction Kinetics

Background:

• The thermal explosion problem with oscillating ambient temperature is a novel area of study with applications in fire autoignition scenarios.
• Understanding the influence of kinetic mechanisms is crucial for accurately predicting critical thermal explosion conditions.
• Previous work established the problem, but the impact of specific kinetic models required further investigation.

Purpose of the Study:

• To investigate the effects of various global kinetic mechanisms on the critical conditions of thermal explosion in a medium with oscillating ambient temperature.
• To analyze the role of reactant consumption in the oscillatory development of thermal explosion.
• To examine the influence of the Zeldovich number on critical thermal explosion parameters.

Main Methods:

• Analysis of thermal explosion dynamics using global kinetic mechanisms: first-order reaction, second-order reaction, and first-order autocatalysis.
• Numerical or analytical modeling to simulate temperature evolution and identify critical boundaries.
• Parametric studies involving the Zeldovich number.

Main Results:

• Kinetic effects related to reactant consumption demonstrably shift critical boundaries for thermal explosion.
• Temperature oscillations during the induction phase are confirmed to occur when reactant consumption is considered.
• Thermal explosion instability naturally develops through prior oscillations, as evidenced by multiple examples.

Conclusions:

• Kinetic mechanisms play a significant role in determining the critical conditions for thermal explosion under oscillating ambient temperatures.
• Oscillatory behavior is an inherent part of the thermal explosion process when reactant consumption is factored in.
• The Zeldovich number also influences the critical conditions, highlighting the complex interplay of factors in thermal explosion phenomena.