Near-Injector Hydrodynamic Perturbation and Its Interplay With Inflow Boundary Conditions in Combustion Simulations

Abstract Combustion simulation has become integral to the industrial design of energy and propulsion systems, serving as an efficient computational tool. Due to the complexity of real engines and thermal power devices, combustors are usually modeled solely with proper boundary conditions to describe inflow and outflow behaviors. In this work, we found that near-injector flow perturbations, often arising from peculiar geometric configurations, can interact with the prescribed inflow boundary conditions, leading to great influence on the predicted flame dynamics, thermoacoustic oscillations, and even statistical results of combustion fields. The objective of this study is to elucidate such an interplay between near-injector hydrodynamic perturbation (NIHP) and the prescribed inflow conditions with the consideration of several commonly used inflow boundary conditions. The receptivity of inflow conditions to NIHP is first examined in a one-dimensional Rijke-tube-like configuration and then demonstrated in the combustion large-eddy simulation of a realistic combustor configuration (thermoacoustically stable). Our findings reveal that inflow conditions exhibiting similar behaviors without NIHP can differ markedly under its influence. This underscores the necessity for careful selection of inflow boundary conditions in combustion simulations when NIHP is present.