The Influence of Thermodiffusive Flame-front Instabilities on Deflagration to Detonation Transition*

The need to reduce carbon emissions has inspired a thorough investigation into alternative fuels. One of the most promising alternatives being researched currently is hydrogen due to its high energy density per mass compared to fuels like gasoline. Some promising ideas for propulsion advancements employ the use of detonations (pulse detonation engines/rotating detonation engines), and as such, understanding the behavior and inception of detonations for fuels like hydrogen is incredibly important. Much research has been conducted concerning how the use of obstructions in the combustion chamber can trigger deflagration to detonation transition (DDT), but little has been focused on how flame-front instabilities in hydrogen can contribute to DDT. This work is focused on quantifying how thermo-diffusive instabilities affect DDT. Direct Numerical Simulations of flames with unity and non-unity Lewis numbers are performed to understand the role instabilities play in DDT. Comparisons of flame-front dynamics between these otherwise identical flames shed light on the impact of thermo-diffusive instabilities.