Numerical investigation of indirect combustion noise in combustor with imposed inlet oscillating velocity: a machine learning optimization

Unwanted consequences linked with entropy waves, such as heightened levels of NOx discharges, combustion instability, and produced sound, have long been acknowledged in the domain. Indirect sound or the acceleration of entropy oscillations act as noise origins that contribute to the instability of the combustion chamber. To acquire a deeper comprehension of these occurrences, an investigation was carried out to computationally explore entropy sound in a lean-premixed ethylene burner. This inquiry made use of the flamelet model and large eddy simulation methods, providing valuable insights into the behavior of entropy undulations and their influence on combustion dynamics. The research specifically concentrated on investigating the impacts of diverse thermal and fluidic conditions on entropy sound in both temperature-wise circulatory and adiabatic combustion chambers. Factors such as inlet turbulence strength, Inlet velocity, stoichiometric ratio, and preheating of the unburned mixture were meticulously scrutinized. The results of the research unveil fascinating correlations between the examined variables and the resultant acoustic response of the system. It was noticed that augmenting the inlet speed, equivalence ratio, and temperature resulted in an escalation in the auditory response. These results imply that higher inlet speed, greater equivalence ratio, and increased temperature circumstances encourage the creation and dissemination of entropy sound. On the other hand, the investigation uncovered that amplifying turbulence intensity had an adverse influence on the conduct of entropy oscillations and consequently diminished the auditory response. This indicates that excessive turbulence intensity can disrupt the spread of entropy waves, diminishing their capability to generate substantial acoustic response.

کلیدواژه ها:

Combustion noise ، Entropy wave ، Lean-premixed combustion ، Indirect combustion noise ، Entropy noise