Modeling of turbulent burning of lean carbon-free mixtures

Research Project, 2024 – 2027

The project aims at contributing to sustainable transition to renewable carbon-free transportation and energetics by building up scientific knowledge and competence on lean turbulent burning of H2 (or NH3 dopped with H2) and developing high-fidelity physics-based Computational Fluid Dynamics (CFD) tools for research into such flames. Developed tools will go far beyond the state of the art by allowing for Differential Diffusion Effects (DDE) that stem from a high molecular diffusivity of H2. While DDE are well documented to be strong even in intense turbulence, numerical models implemented into modern CFD software failed in predicting strong DDE. Unless the problem is solved, utility of CFD tools for R&D of engines that burn lean H2-containing mixtures is limited. To bridge this knowledge gap, state-of-the-art direct numerical simulation data obtained from complex-chemistry lean H2/air turbulent flames will be analyzed (within both Reynolds-Averaged Navier-Stokes and Large Eddy Simulation frameworks) using target-directed diagnostic techniques. The focus of the analysis will be placed on (i) dynamics and structure of zones characterized by the highest fuel consumption rate and localized to the leading edge of flame brush, (ii) molecular fluxes of fuel and heat to and from, respectively, such zones, and (iii) the influence of DDE on probability density functions of local flame characteristics. Developed models will be validated in simulations of laboratory experiments.