The use of OH* and CH* as heat release markers in combustion dynamics. (December 2017)

• Record Type: Journal Article
• Authors: Sardeshmukh, Swanand; Bedard, Michael; Anderson, William
• Is Part Of: International journal of spray and combustion dynamics. Volume 9:Number 4(2017)
• Page Start: 409
• Page End: 423
• Publication Date: 2017-12
• Subjects: Chemiluminescence -- rocket combustion instability -- time accurate Computational Fluid Dynamics (CFD) -- detailed kinetics; Combustion engineering -- Periodicals; Fluid dynamics -- Periodicals; Combustion -- Periodicals; Spraying -- Periodicals; Combustion; Combustion engineering; Fluid dynamics; Spraying; Periodicals; 541.361
• DOI: 10.1177/1756827717718483
• Languages: English
• ISSNs: 1756-8285

Abstract

The study examines chemiluminescence measurements and computations as a method of validation. Because chemiluminescent radicals are present in small concentrations and associated timescales are also small, a common assumption is that these are quasi-steady-state species and their transport can be ignored. This paper examines the above assumption using available data and simulation results, specifically aiming at a single element rocket combustor under strong pressure fluctuations. Variations in the kinetics rate constants are considered for assessing sensitivity of the results. Two additional aspects are explored: the ability of the excited species to represent the chemical heat release and the optical thickness of the medium. For the conditions of the study, the quasi-steady-state assumption in the case of OH* is found to be marginally insufficient while in the case of CH*, it is found to be acceptable. Modeled heat release is qualitatively better captured by CH* than OH* because of higher difference in the peak to asymptotic concentrations and lower ground state concentration.