Master's Thesis Proposal

Sathvik Gujjati 

(Advisor: Prof. Suresh Menon)

Modeling Combustion Noise and Parametric Sensitivity in a RQL Combustor

Using Large Eddy Simulations

Wednesday, November 4 

12:00 p.m. 

Weber 200

Abstract 

The Rich Burn-Quick Mix-Lean Burn (RQL) combustor is designed with a goal to reduce NOx emissions further in compliance with sustainable transportation goals. While the RQL combustor has been proven to reduce NOx emissions significantly, the staged combustion processes often are highly unstable and the noise due to the combustion process leads to a complex acoustic behavior during operation. This has direct consequences for overall engine performance. Hence, modeling the acoustic behavior of the combustion process is important. The purpose of this thesis is to develop an understanding of the acoustic signature of this combustor. Large Eddy Simulations (LES) are used to simulate the combustor across two inlet air temperatures and varying Fuel Air Ratio (FAR). Using multiple acoustic post-processing approaches, an understanding of the tonal noise peaks due to the combustion process is obtained using LES datasets. Additionally, to further analyze the modes of these tonal peaks, a 3D Spectral Proper Orthogonal Decomposition (SPOD) algorithm is implemented across the combustor to model coherent acoustic features. Flame dynamics analysis is further pursued to understand the nature of coupled acoustics and heat release. The results show inlet air temperature variation driving the acoustic variation with FAR amplifying the effect at lower values. A low-temperature high-FAR case shows a deviation from observed tonal peaks. SPOD establishes acoustic visualization to interpret coupled acoustic flow variations.

Committee 

• Prof. Suresh Menon – School of Aerospace Engineering (advisor) 
• Prof. Joseph Oefelein– School of Aerospace Engineering 
• Prof. Krishan K Ahuja – School of Aerospace Engineering