LES-based prediction of technically premixed flame dynamics and comparison with perfectly premixed mode

The present study combines Large Eddy Simulation (LES) with System Identification (SI) to determine the Flame Transfer Functions (FTFs) of technically premixed flames that respond fluctuations upstream velocity as well equivalence ratio. Two variants obtain corresponding FTFs from numerically determined time series data are reported and compared experimental results. experiment does not measure heat release rate directly but instead CH * chemiluminescence. This is insufficient for FTF identification can be used validation simulation. We implemented a post-processor in simulation validated experiment. After validation, identify contributions ratio flame dynamics. propose compare two approaches FTFs. direct approach via multiple-input single-output system requires one simultaneous excitation fuel air inlets carefully chosen input signals. second reconstructs decomposition separate simulations, perfectly premixed, reduced requirements on signal quality. both discuss flames. Overall, LES/SI proved flexible reliable