Supersonic Spray Combustion

High-Speed Drag Models for Supersonic Spray Combustion Application
Oh, H. and Ladeinde, F., AIAA Propulsion and Energy 2021 Forum, 9-11 August 2021, Denver, CO, Paper AIAA-2021-3527
https://doi.org/10.2514/6.2021-3527

Abstract
The motivation for the present study is its relevance to supersonic spray combustion, such as in scramjet engines where liquid fuels are used. Evaluating various drag, heat and mass transfer models for two-phase high-speed flows is undertaken in this study as a path to achieving our ultimate objectives. In this work, several models for hydrodynamic drag coefficient in high-speed flows are introduced and three first order differential equations appropriate for supersonic flows that carry particles are solved. The results show that the models by Crowe and Hermsen show similar profiles. As the particle approaches the exit of the nozzle, better results can be obtained by Crowe’s model.

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Fig. 2. Comparison of high-speed liquid drop models as functions of: (a) the particle velocity, (b) time, (c) flow Mach number, (d) particle Mach number, (e) drag, and (f) particle Reynolds number

Progress in Supersonic Spray Combustion Modeling
Ladeinde, F., AIAA SciTech 2020 Forum 6-10 January 2020, Orlando, FL, Paper AIAA2020-0874 (2020)
https://doi.org/10.2514/6.2020-0874

Abstract
This paper represents a limited review of available studies on supersonic spray combustion (SSC), for which there is not a lot that have addressed the various aspects of the real problem, which include drop breakup, drop evaporation, the role of shock waves, turbulence, potentially complicated drag laws when the point-particle method is used, and combustion. A few previous studies representing the modes of drop breakup and shattering by shock waves are presented in this paper, including a few analyses by others on this phenomenon. At present, most of the models are from empirical studies. There have been a few studies, mostly exploratory, by the author, and a handful of CFD-based simulations of the SSC problem, but these incidentally have not addressed the complexities in the real problem. There are a few studies on aeration, as in barbotage and water spray quenching of fire. However, the drops in this case are not fuels, and so do not undergo combustion. A more detailed version of this review is underway.