Flame evolution in shock-accelerated flow under different reactive gas mixture gradients.

Area of Science:

• Combustion physics
• Fluid dynamics
• Computational science

Background:

• Understanding shock-wave/flame interactions is crucial for predicting combustion phenomena.
• Initial conditions, such as reactive gas mixture gradients, can influence these complex interactions.

Purpose of the Study:

• To numerically investigate the interaction between a planar shock wave and a spherical flame.
• To analyze the influence of varying initial reactive gas mixture gradients on flame evolution and detonation emergence.
• To examine the factors contributing to vorticity generation during shock-accelerated flow.

Main Methods:

• High-resolution computational simulations were employed to model the shock-flame interaction.
• Numerical experiments were conducted for homogeneous and inhomogeneous ethylene-oxygen-nitrogen mixtures.
• Analysis focused on flame evolution, shock dynamics, heat release, and vorticity generation.

Main Results:

• Detonation was observed exclusively in homogeneous mixtures; inhomogeneous mixtures resulted in shock bifurcation.
• Flame volume and heat release rate were influenced by mixture gradients, with uniform/positive gradients increasing them and negative gradients decreasing them.
• Vorticity generation was primarily driven by compression, except in the homogeneous case before shock-flame impingement, where baroclinic effects dominated.

Conclusions:

• Initial reactive gas mixture gradients significantly alter shock-flame interaction dynamics, affecting flame propagation and detonation.
• The study highlights the distinct shock dynamics and flame behavior in homogeneous versus inhomogeneous reactive flows.
• Understanding vorticity generation mechanisms is key to comprehending the complex fluid dynamics involved in shock-accelerated combustion.