Effect of N2 dilution and preheat temperature on combustion dynamics of syngas in a reverse-flow combustor

Pramanik, S and Ravikrishna, RV (2020) Effect of N2 dilution and preheat temperature on combustion dynamics of syngas in a reverse-flow combustor. In: Experimental Thermal and Fluid Science, 110 .

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Abstract

The present study investigates the combustion dynamics of low-calorific value syngas in the reverse-flow configuration at P = 1 atm using OH* chemiluminescence (5 kHz), noise (50 kHz), and emissions (NOx and CO) measurements. The combustion dynamics have been investigated as a function of the global equivalence ratio (0.32–0.89), percentage O2 in the coflow (7.6–21%), and the oxidizer preheat temperature (~400–800 K). The variation of these parameters resulted in different operating conditions such as conventional, ultra-lean, transition, and MILD combustion modes. For all the cases, autoignition kernels were observed and appear to be a possible mode of flame stabilization - highlighting the role of H2 in reducing the ignition delay. The combustion chamber demonstrated stable operation over the range of equivalence ratio and percentage O2 investigated, with the conventional mode displaying the highest SPL and fluctuations in the reaction zone (OH*). The most stable operation was obtained for the MILD case where the SPL decreased by ~6 dB caused by a suppression of the high-frequency (>800 Hz) longitudinal modes. However, the operation of the combustion chamber became unstable as the oxidizer preheat temperature decreased from 603–547 K due to the emergence of very high-frequency (~9–15 kHz) oscillations.

Item Type:	Journal Article
Publication:	Experimental Thermal and Fluid Science
Publisher:	Elsevier Inc.
Additional Information:	The copyright for this article belongs to Elsevier Inc.
Keywords:	Chemiluminescence; Combustion chambers; Dynamics; Functions; Preheating; Synthesis gas, Combustion dynamics; Different operating conditions; Flame stabilization; Global equivalence ratio; Noise; Reverse flow; Syn-gas; Very high frequency, Reverse combustion
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	08 Feb 2023 11:05
Last Modified:	08 Feb 2023 11:05
URI:	https://eprints.iisc.ac.in/id/eprint/80083

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