Flow-acoustic Characterisation of a Cavity-based Combustor Configuration

Krishna Kant Agarwal; R. V. Ravikrishna

doi:10.14429/dsj.61.870

Krishna Kant Agarwal Indian Institute of Science, Bengaluru
R. V. Ravikrishna Indian Institute of Science, Bengaluru

DOI: https://doi.org/10.14429/dsj.61.870

Keywords: Flow-acoustics, cavity combustor, turbulent reacting flow, unsteady flow, cavity fluid mechanics

Abstract

This study concerns the flow-acoustic characterisation of a cavity-based combustor configuration. A well-validated numerical tool has been used to simulate the unsteady, two-dimensional reacting flow. Initially, a conventional flow over a cavity with dimensions and conditions corresponding to a compact cavity combustor was studied. Cavity mass injections in the form of fuel and air injections required for trapped vortex formation were then employed and the resonance features of this configuration were studied. The results indicate that the cavity depth mode resonance mechanism is dominant at the conditions studied in this work and that the oscillation frequencies do not change with cavity air injection. This observation is important since it implies that the only important variable which can alter resonant frequencies is the cavity depth. With combustion, the pressure oscillation amplitude was observed to increases significantly due to periodic entrainment of the cavity air jet and fluctuation of fuel-air mixture composition to produce highly fluctuating heat-release rates. The underlying mechanisms of the unsteady flow in the cavity combustor identified in this study indicate the strong dependence of the acoustics on the cavity injection strategies.

Defence Science Journal, 2011, 61(6), pp.523-528, DOI:http://dx.doi.org/10.14429/dsj.61.870

Author Biographies

Krishna Kant Agarwal, Indian Institute of Science, Bengaluru

Mr Krishna Kant Agarwal obtained BE(H) (Marine Engineering) from Marine Engineering and Research Institute, Jadavpur University, Kolkata. Currently pursuing his PhD from Combustion and Spray Laboratory, Department of Mechanical Engineering, Indian Institute of Science (IISc), Bengaluru. His area of research includes: Unsteady turbulent combustion simulations using KIVA-3V, experiments on a compact cavity-based combustor concept.

R. V. Ravikrishna, Indian Institute of Science, Bengaluru

Prof R.V. Ravikrishna obtained his PhD (Mechanical Engineering) from Purdue University, USA. Presently working as an Associate Professor in the Combustion and Spray Laboratory, Department of Mechanical Engineering, IISc, Bengaluru. His area of research includes: Combustion and flow diagnostics using laser-based techniques, spray diagnostics, IC engine in-cylinder processes, alternate fuels, novel combustor development, computational fluid dynamics. He has been awarded with INAE Young Engineer Award in 2004. He has more than 80 research papers in national/international journals and conferences.