Supersonic combustion of hydrogen using an improved strut injection scheme. (1st March 2019)

• Record Type: Journal Article
• Authors: Aravind, S.; Kumar, Rajiv
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 12(2019)
• Page Start: 6257
• Page End: 6270
• Publication Date: 2019-03-01
• Subjects: Scramjet -- Strut injector -- Supersonic combustion -- Turbulent flows -- Mixing -- CFD; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.01.064
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Numerical investigation of mixing is performed at Mach 2.0 model Scramjet combustor employing parallel strut injection schemes for fuel. In the present investigation, basic strut injector is modified in such a way to produce additional vortices in streamwise direction and improve fuel-air mixing. Air is injected at Mach 2.0 at the combustor inlet and fuel is injected at sonic speed from the blunt end of the strut. The flow field involving high-speed turbulent mixing and heat addition was modeled by three-dimensional Reynolds averaged Navier-Stokes equations. A realizable k-ε model was chosen to close the turbulence problem with the default model constants. Non-premixed combustion of hydrogen and air is modeled using the mixture fraction β-pdf framework. Turbulence-chemistry interactions are handled by a strained flamelet model. Comparisons of numerical results with experimental results have demonstrated the accuracy and applicability of computational grid and a numerical scheme for hot and cold flow solutions. The shock-shear layer interaction present within the combustor increases the local turbulent intensity and has a positive effect on mixing. The mixing efficiency obtained with improved strut injector is compared with the basic strut. Improved strut injection scheme showed a mixing efficiency of >95% with a 45% reduction in length. Further combustion efficiency is calculated in the streamwise direction and plot follows the similar trend as the mixing efficiency. The proposed modification of strut geometry showed improved mixing and combustion performance. Highlights: Turbulence chemistry modeled by flamelet accurately predicts reaction features. Mixing of air and fuel is strongly influenced by vortices and turbulence. Total pressure loss within the supersonic combustor is due to shocks and vortices. Shock increases mixing locally by increasing the turbulent kinetic energy. Length of mixing efficiency >95% is reduced by 15 mm by modified strut injector.