Validation of CFD++ code capability for supersonic combustor flowfields

Goldberg, U.; Peroomian, Oshin; Chakravarthy, Sukumar; Sekar, Balu; Branch, Components; Afb, Wright Patterson

doi:10.2514/6.1997-3271

Cited by 32 publications

(10 citation statements)

References 6 publications

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“…Viscous flowfields in the presence of fuel injection are computed by using the state-of-the-art commercial solver CFD++ [30,31], which has been employed by the Australian hypersonics network for scramjet research due to its demonstrated fidelity in hypersonic aerodynamics and aerothermodynamics [7,20,25,32,33]. An implicit algorithm with second-order spatial accuracy is used to solve the Navier-Stokes equations for steady flowfields, and convergence is accelerated by the multigrid technique [34].…”

Section: B Computational Fluid Dynamics 1 Solvermentioning

confidence: 99%

Mixing Characteristics of Inclined Fuel Injection via Various Geometries for Upstream-Fuel-Injected Scramjets

Ogawa

2015

Journal of Propulsion and Power

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Efficient fuel/air mixing plays a crucial role in successful operation of hypersonic airbreathing engines, particularly scramjets, where fuel must be injected into high-speed crossflow and mixed with air at an extremely short timescale. This paper presents the results of a numerical study that investigates the effects of various orifice shapes on fuel mixing characteristics into hypersonic airflow at Mach 5, aiming at the application to scramjet operation with upstream fuel injection at Mach 10. The performance of the injectors at an inclination angle of 45 deg are assessed with respect to various criteria such as the mixing efficiency, streamwise circulation, total pressure recovery, fuel penetration, and spread. Streamwise slot injectors have been found to yield higher mixing efficiency than the other injectors tested (namely, square, circular, diamond, and triangular injectors), owing to the buffering effects. Apparent higher total pressure recovery has been obtained with these rectangular injectors, but their advantages have diminished significantly with the alignment of the trailing-edge position. The highest vertical penetration has been achieved by the square injector, whereas the performances of other injectors with a sharp leading edge have been found to be affected considerably by the axis switch phenomenon due to inclined injection at higher injection pressure. A major influence of the fore and aft shapes of the orifice has been observed on the three-dimensional bow shock formation and wake recirculation, respectively. Nomenclature A = cross section at a streamwise station AR = aspect ratio (streamwise/spanwise) A j = injector area on floor, m 2 A n j = injector area normal to jet, m 2 c = mass fraction c H 2 = hydrogen mass fraction c O 2 = oxygen mass fraction c s = stoichiometric mass fraction D = effective injector diameter, m H = height of computational domain, m h f = fuel penetration height J = jet-to-freestream momentum flux ratio L = length of computational domain, m L 0 = distance to upstream end of injector, m _ m = mass flow rate, kg∕s p = static pressure, Pa p 0 = total pressure, Pa p 02 = pitot pressure, Pa U = crossflow velocity, m∕s W = domain width (injector spacing), m w f = lateral fuel spread x = streamwise direction, m y = spanwise direction, m z = vertical direction, m α j = injection angle, deg Γ = streamwise circulation γ= specific heat ratio Δp 0 = total pressure loss, Pa η m = mixing efficiency Φ = fuel/air equivalence ratio χ m = overall mesh refining factor χ m xy = refining factor in x and y directions χ m z = refining factor in z direction ω x = streamwise vorticity, ∕s Subscripts j = jet property STA = stream-thrust-averaged value ∞ = freestream property

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Section: B Computational Fluid Dynamics 1 Solvermentioning

confidence: 99%

Mixing Characteristics of Inclined Fuel Injection via Various Geometries for Upstream-Fuel-Injected Scramjets

Ogawa

2015

Journal of Propulsion and Power

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“…Since the development of this solver called rhoFoam, OpenFOAM has had major changes in the thermophysical modeling. Figure 1 shows the geometry and boundary conditions used by Lorrain et al [6] for study of the finite-rate chemistry mechanisms governing the combustion process with CFD++ [52]. As it can be seen in the upper representation, the full geometry consists of an inlet (sharp leading edge) with two ramps leading to the constant area combustor which terminates in an exit nozzle.…”

Section: Lorrain's Scramjetmentioning

confidence: 99%

Numerical Modeling and Simulation of Supersonic Flows in Propulsion Systems by Open-Source Solvers

Hoste

Casseau

Fossati

et al. 2017

21st AIAA International Space Planes and Hypersonics Technologies Conference

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Two open-source solvers, Eilmer and hyFoam, are here considered for their performance in simulating high-speed flows in different flow conditions and geometric configurations typical of propulsive systems at supersonic speeds. The goal is to identify the open-source platform providing the best compromise between accuracy, flexibility and computational cost to eventually simulate the flow fields inside ramjet and scramjet engines. The differences in terms of discretization and solution methods of the selected solvers are discussed in terms of their impact on solution accuracy and computational efficiency and in view of the aerothermodynamic analysis and design of future transatmospheric propulsive systems. In this work steady state problems are considered. Numerical results of two scramjet type engines demonstrated a similar predictive capability of both codes in non-reacting conditions. These results highlight their potential to be considered for further characterization of overall engine performance. * PhD Candidate, AIAA Student Member. † Lecturer, AIAA Member . ‡ Senior Lecturer.

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“…Of particular importance is the fact that CFD has been subjected to extensive codevalidation work. The reader is referred to various works in the literature for further information on the code and the code validation (for example, [15]). The mesh consisted of 80 node points in the vertical direction and 798 points in the axial direction.…”

Section: Numerical Toolsmentioning

confidence: 99%

“…The numerical tool employed here for the combustion flowfield simulations is the commercial computational fluid dynamics (CFD) code CFD [15]. CFD can solve both the steady or unsteady compressible and incompressible Navier-Stokes equations, including multispecies and finite-rate-chemistry modeling.…”

Section: Numerical Toolsmentioning

confidence: 99%

Radical-Farm Ignition Processes in Two-Dimensional Supersonic Combustion

McGuire

Boyce

Mudford

2008

Journal of Propulsion and Power

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A two-dimensional numerical study was performed of the ignition processes associated with the concept of radical farming for supersonic combustion. In a preliminary parametric study, a range of freestream conditions attainable in a hypersonic shock tunnel was investigated and mapped according to whether or not the behavior known as radical farming is present: a combustion-induced pressure rise in second or subsequent hot pockets rather than the first. Two such cases were analyzed in detail, both having mean conditions across the combustion-chamber entrance that would result in extremely long ignition lengths. The initiation, branching cycle, and heat release reactions in the combustion process become active in the radical farm, and H and OH radicals are produced. Their rate of production slows in the regions of flow expansion, but does not approach chemical freezing until toward the end of the localized expansion zones. Simultaneously, heat release elevates the local temperature. When the mixture flows through the shock at the second hot pocket, the elevated temperature and the presence of radicals enable the branching cycle and three-body recombination heat release reactions to accelerate, and significant pressure rise due to heat release is then able to occur. The extent to which this is completed in the second hot pocket depends on the inflow conditions.

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Validation of CFD++ code capability for supersonic combustor flowfields

Cited by 32 publications

References 6 publications

Mixing Characteristics of Inclined Fuel Injection via Various Geometries for Upstream-Fuel-Injected Scramjets

Mixing Characteristics of Inclined Fuel Injection via Various Geometries for Upstream-Fuel-Injected Scramjets

Numerical Modeling and Simulation of Supersonic Flows in Propulsion Systems by Open-Source Solvers

Radical-Farm Ignition Processes in Two-Dimensional Supersonic Combustion

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