DNS of High-Karlovitz Number Turbulent Premixed Flames under Engine-Relevant Conditions
09:30 - 10:00
Level 0 lecture hall between Al-Jazri and Al-Kindi (buildings 4 and 5)
Recent advances in high-performance computing and large-scale direct numerical simulations (DNS) have allowed detailed exploration of the reacting flow dynamics in extreme, previously inaccessible regimes characterized by high flow speeds, significant compressibility effects, and strong coupling between exothermic reactions and the turbulent flow. Such combustion regimes are fundamental to the operation of many modern propulsion applications from scramjets to detonation-based engines. Furthermore, in certain cases these regimes can now be studied with remarkable realism using full-scale combustors, realistic fuels, and engine-relevant conditions. This talk will present an overview of a range of phenomena recently observed by us in DNS of high-speed, premixed, turbulent reacting flows. In particular, the talk will focus on two topics: 1) qualitative changes in the nature of the turbulent cascade in the presence of exothermic reactions and the onset of catastrophic transitions, e.g., spontaneous detonation formation; and 2) structure of turbulent premixed flames in jet fuels at high pressures over a broad range of turbulent conditions with Karlovitz numbers from 10 to 104. I will discuss challenges presented by these findings both in the context of our theoretical understanding of reacting flows, and also in the context of modern modeling paradigms, such as Large Eddy Simulations.