References of "Pitsch, Heinz"
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See detailAn efficient flamelet-based combustion model for compressible flows
Saghafian, Amirreza; Terrapon, Vincent ULg; Pitsch, Heinz

in Combustion and Flame (2014)

A combustion model based on a flamelet/progress variable approach for high-speed flows is introduced. In the proposed formulation, the temperature is computed from the transported total energy and ... [more ▼]

A combustion model based on a flamelet/progress variable approach for high-speed flows is introduced. In the proposed formulation, the temperature is computed from the transported total energy and tabulated species mass fractions. Only three additional scalar equations need to be solved for the combustion model. Additionally, a flamelet library is used that is computed in a pre-processing step. This approach is very efficient and allows for the use of complex chemical mechanisms. An approximation is also introduced to eliminate costly iterative steps during the temperature calculation. To better account for compressibility effects, the chemical source term of the progress variable is rescaled with the density and temperature. The compressibility corrections are analyzed in an a priori study. The model is also tested in both Reynolds-averaged Navier–Stokes (RANS) and large-eddy simulation (LES) computations of a hydrogen jet in a supersonic transverse flow. Comparison with experimental measurements shows good agreement, particularly for the LES case. It is found that the disagreement between RANS results and experimental data is mostly due to the mixing model deficiencies and the presumed probability density functions used in the RANS formulation. A sensitivity study of the proposed model shows the importance of the compressibility corrections especially for the source term of the progress variable. [less ▲]

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See detailReynolds-Averaged Navier-Stokes Simulations of the HyShot II Scramjet
Pecnik, Rene; Terrapon, Vincent ULg; Ham, Frank et al

in AIAA Journal (2012), 50(8), 1717-1732

The internal flow in the HyShot II scramjet is investigated through numerical simulations. A computational infrastructure to solve the compressible Reynolds-Averaged Navier-Stokes equations on ... [more ▼]

The internal flow in the HyShot II scramjet is investigated through numerical simulations. A computational infrastructure to solve the compressible Reynolds-Averaged Navier-Stokes equations on unstructured meshes is introduced. A combustion model based on tabulated chemistry is considered to incorporate a detailed chemical kinetics mechanics while retaining a low computational cost. Both non-reactive and reactive simulations have been performed and results are compared with ground test measurements obtained at DLR. Different turbulence models were tested and the dependence on the mesh is assessed through grid refinement. The comparison with experimental data shows good agreement, although for the reactive case the computed heat fluxes at the wall are higher than measurements. A sensitivity analysis on the turbulent Schmidt and Prandtl numbers shows that the choice of these parameters has a strong influence on the results. In particular, variations of the turbulent Prandtl number lead to large changes in the heat flux at the walls. Finally, the inception of thermal choking is investigated by increasing the equivalence ratio, whereby a normal shock is created locally and moves upstream leading to a large increase in the maximum pressure. Nevertheless a large portion of the flow is still supersonic. [less ▲]

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See detailAn Efficient Flamelet-based Combustion Model for Supersonic Flows
Saghafian, Amirreza; Terrapon, Vincent ULg; Ham, Frank et al

in 17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference 2011, Vol. 2; No AIAA 2011-2267 (2011, April)

A combustion model based on a Flamelet/Progress Variable approach for high-speed flows is introduced. In the proposed formulation, the temperature is computed from the transported total energy and ... [more ▼]

A combustion model based on a Flamelet/Progress Variable approach for high-speed flows is introduced. In the proposed formulation, the temperature is computed from the transported total energy and tabulated species mass fractions. The combustion is thus modeled by 3 additional scalar equations and a chemistry table that is computed in a pre-processing step. This approach is very efficient and allows the use of complex chemical mechanisms. An approximation is also introduced to eliminate costly iteration steps during the temperature calculation. To better account for compressibility e ects, the source term for the progress variable is rescaled with the pressure. The model is tested in both RANS and LES computations of a hydrogen jet in a supersonic transverse flow. Comparison with experimental measurements shows good agreement, particularly in the LES case. It is also found that the disagreement between RANS results and experimental data is mostly due to the mixing model de ciencies used in RANS. [less ▲]

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See detailAssessment of the combustion characteristics of hydrogen transverse jets in supersonic crossflow
Gamba, Mirko; Terrapon, Vincent ULg; Saghafian, Amirreza et al

in Annual Research Briefs (2011)

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See detailFull-system RANS of the HyShot II scramjet Part 2: Reactive cases
Terrapon, Vincent ULg; Pecnik, Rene; Ham, Frank et al

in Annual Research Briefs (2010)

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See detailA flamelet-based model for supersonic combustion
Terrapon, Vincent ULg; Ham, Frank; Pecnik, Rene et al

in Annual Research Briefs (2009)

Detailed reference viewed: 43 (2 ULg)