Numerical exploration of dissimilar supersonic coaxial jets mixing. (June 2015)

• Record Type: Journal Article
• Authors: Dharavath, Malsur; Manna, P.; Chakraborty, Debasis
• Is Part Of: Acta astronautica. Volume 111(2015)
• Page Start: 308
• Page End: 316
• Publication Date: 2015-06
• Subjects: CFD -- Convective Mach number -- Dissimilar gases; Astronautics -- Periodicals; Outer space -- Exploration -- Periodicals; Astronautics; Periodicals; 629.405
• DOI: 10.1016/j.actaastro.2015.03.001
• Languages: English
• ISSNs: 0094-5765

Abstract

Abstract: Mixing of two coaxial supersonic dissimilar gases in free jet environment is numerically explored. Three dimensional RANS equations with a k–ε turbulence model are solved using commercial CFD software. Two important experimental cases (RELIEF experiments) representing compressible mixing flow phenomenon under scramjet operating conditions for which detail profiles of thermochemical variables are available are taken as validation cases. Two different convective Mach numbers 0.16 and 0.70 are considered for simulations. The computed growth rate, pitot pressure and mass fraction profiles for both these cases match extremely well with experimental values and results of other high fidelity numerical results both in far field and near field regions. For higher convective Mach number predicted growth rate matches nicely with empirical Dimotakis curve; whereas for lower convective Mach number, predicted growth rate is higher. It is shown that well resolved RANS calculation can capture the mixing of two supersonic dissimilar gases better than high fidelity LES calculations. Highlights: Mixing of coaxial supersonic free jets of dissimilar gases is numerically explored. Two different convective Mach numbers 0.16 and 0.70 are considered. Three dimensional RANS equations with the k–ε turbulence model are solved. Computed growth rate and flow profiles match well with experimental results. Well resolved RANS results can perform as good as high fidelity LES results.