Diagnostic investigation of reacting flow characteristics of a cavity based scramjet with multiple bumps

Natarajan, V and Manikandan, S and Jegannath, M and Thangavel, K and Sathyan, P and Murugesh, P and Sanal Kumar, VRS and Nejaamtheen, MN (2017) Diagnostic investigation of reacting flow characteristics of a cavity based scramjet with multiple bumps. In: 53rd AIAA/SAE/ASEE Joint Propulsion Conference, 10-12 July 2017, Atlanta,Georgia , USA.

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Abstract

The design optimization of cavity based scramjet combustor is an active research topic worldwide. In this paper an attempt has been made to increase the combustor efficiency of the scramjet combustor by introducing multiple bumps facilitated to its cavity for increasing the residence time within the given envelope lucratively. The comprehensive numerical studies have been carried out using a 2D unsteady, density based first order implicit SST k-7omega; turbulence model with the eddy dissipation concept reacting species. In the numerical modeling the air, the primary flow, is injected axially and the hydrogen fuel, the secondary flow, is injected perpendicular to the primary flow from a pre-determined location of 1.4 times the inlet diameter of the scramjet combustor from its rear end. The preliminary results show wide varieties of flow features resulting from the interactions between the primary and secondary flows, the shock waves-boundary layer interactions, and the cavity flows. We found that the cavity based scramjet combustor with bumps provides greater average exit temperature than the case without bumps. Our parametric analytical studies with different bump shapes reveal that the shape and size of the bump is having reasonable bearing on increasing the average combustion temperature with minimum combustor length. Among the three different bump shapes considered in our analyses, viz., hemispherical, spike and inclined spike we observed that the highest average temperature is achived at the steady state for the case with inclined spike towards the primary flow. Detailed analyses reveal that the scramjet combustor with bumps provide better mixing of fuel and air by creating favourable recirculation bubbles for increasing the residence time leading to enhancing the combustion efficiency. This study is a pointer towards for the prudent geometry design optimization of cavity based scramjet combustors with multiple bumps.

Item Type:	Conference Paper
Publication:	53rd AIAA/SAE/ASEE Joint Propulsion Conference, 2017
Publisher:	American Institute of Aeronautics and Astronautics Inc, AIAA
Additional Information:	cited By 0; Conference of 53rd AIAA/SAE/ASEE Joint Propulsion Conference, 2017 ; Conference Date: 10 July 2017 Through 12 July 2017; Conference Code:195549
Keywords:	Boundary layers; Combustion; Combustors; Efficiency; Hydrogen fuels; Oceanography; Propulsion; Secondary flow; Shock waves; Turbulence models, Combustion efficiencies; Combustion temperatures; Combustor efficiency; Design optimization; Eddy dissipation concept; Recirculation bubbles; Scramjet combustors; Shock waves-boundary layer interaction, Ramjet engines
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	15 Oct 2020 10:18
Last Modified:	15 Oct 2020 10:18
URI:	http://eprints.iisc.ac.in/id/eprint/65786

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