Quasi-1D modeling of heat release for the study of longitudinal combustion instability

A method for obtaining combustion response functions from experiments or detailed computational fluid dynamic (CFD) analyses is described and used in a quasi one dimensional approach for the study of longitudinal combustion instability. The goal is to reproduce the behavior of several geometrical configurations of a single element combustor, once a suitable heat release response function is inferred from high fidelity data. In particular, results of detailed two-dimensional hybrid RANS-LES simulations of an unstable geometrical configuration of the Continuously Variable Resonance Combustor (CVRC) have been considered for response function calibration. Results, obtained with this calibration by the quasi-one dimensional approach, show that the pressure limit cycle is well captured. A parametric analysis on quantities controlling response function properties is carried out to show its sensitivity to each of them. The response function from this single condition is then applied to different geometrical configurations of CVRC to predict a stability map that is consistent with experimental results available in the literature.