An Attempt to Include Thermo-Diffusive Instabilities in the Thickened Flame Model: a Case Study

Abstract The accurate prediction of thermo-diffusive instabilities in lean hydrogen flames is crucial for the design and optimization of industrial combustion systems. Current numerical models, even those employing high-fidelity computational fluid dynamics (CFD) techniques, often struggle to capture these small-scale phenomena due to limitations in spatial and temporal resolution. This leads to inaccuracies in predicting turbulent flame speeds and can hinder the prevention of undesirable events like flashback. To address this challenge, this study investigates a methodology based on freely propagating flames to characterize the impact of thermo-diffusive instabilities on hydrogen consumption speeds. By extending the work of Gaucherand et al. [1], we explore the influence of varying strain rates on the turbulent flame speed. The proposed approach is validated against experimental data from the NTNU bluff-body stabilized burner, a configuration known to be susceptible to thermo-diffusive instabilities. Comparative analyses with and without the inclusion of thermo-diffusive instabilities will be presented to demonstrate the significance of these effects on the overall flame dynamics.