PeleLM-FDF Large Eddy Simulator of Turbulent Combustion

TL;DR

The PeleLM-FDF methodology combines Eulerian and Lagrangian approaches for high-fidelity LES of turbulent combustion, accurately capturing complex phenomena like flame extinction and re-ignition at a fraction of DNS cost.

Contribution

A hybrid PeleLM-FDF computational scheme for LES of turbulent combustion that effectively models intricate physics with high accuracy and reduced computational expense.

Findings

Excellent agreement with DNS data on thermo-chemical statistics

Captures flame-extinction and re-ignition phenomena

Operates at 1/512 of DNS computational cost

Abstract

A new computational methodology, termed "PeleLM-FDF" is developed and utilized for high fidelity large eddy simulation (LES) of complex turbulent combustion systems. This methodology is constructed via a hybrid scheme combining the Eulerian PeleLM base flow solver with the Lagrangian Monte Carlo simulator of the filtered density function (FDF) for the subgrid scale reactive scalars. The resulting methodology is capable of simulating some of the most intricate physics of complex turbulence-combustion interactions. This is demonstrated by LES of a non-premixed CO/H$_2$ temporally evolving jet flame. The chemistry is modelled via a skeletal kinetics model, and the results are appraised via detail a posteriori comparisons against direct numerical simulation (DNS) data of the same flame. Excellent agreements are observed for the time evolution of various statistics of the thermo-chemical quantities, including the manifolds of the multi-scalar mixing. The new methodology is capable of capturing the complex phenomena of flame-extinction and re-ignition at a 1/512 of the computational cost of the DNS. The high fidelity and the computational affordability of the new PeleLM-FDF solver warrants its consideration for LES of practical turbulent combustion systems.