A dynamic pressure-sink method for improving large eddy simulation and hybrid Reynolds-averaged Navier–Stokes/large eddy simulation of wall-bounded flows

Proceedings of the Institution of Mechanical Engineers, Part G:

et al. 2013

The characteristics of cavity-based supersonic flow and combustion in a scramjet combustor are investigated both experimentally and numerically. Cavities with depth D = 8 mm, length-to-depth ratio L/D = 4 or 7 and aft angle A = 22.5, 45 or 90° are considered. In non-reacting flows, the cavity shear layer dives deeper into the cavity with decreasing aft angle, resulting in a more intense impingement of the shear layer on the aft wall and a stronger trailing edge shock but weaker oscillations within the cavity as well as a smaller penetration of the upstream-injected hydrogen jet. The cavity with larger aft angle is beneficial to promote the instabilities evolving in the jet-mixing layer and accelerate the breakdown of the counter-rotating vortices, resulting in more rapid fuel–air mixing. In reacting flows, the cavity with larger aft angle also exhibits stronger oscillations and higher combustion efficiency with no greater total pressure loss. The results indicate that cavities with larger aft angle may be more beneficial to enhance the supersonic mixing and combustion as long as the oscillations are not too violent to induce blowout or blowoff of the cavity-stabilized combustion.

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Section: Experimental and Numerical Descriptionsmentioning

confidence: 99%

Experimental and numerical investigation of cavity-based supersonic flow and combustion

Proceedings of the Institution of Mechanical Engineers, Part G:

et al. 2013

show abstract

“…The general theoretical framework has been discussed and testified in the early works. 9,16,19,26 Additionally, a simulation of transverse jet in a supersonic turbulent crossflow, experimentally studied by Santiago and Dutton, 27 Everett et al. 28 and Vanlerberghe et al., 29 is carried out to validate the present numerical models.…”

Section: Physical Models and Numerical Methodsmentioning

confidence: 94%

“…Here, the values of Cμ and C d need to be determined. According to the previous discussion, 16 Cμ=0.02075 and Cd=1.0 are used in the present work.…”

Section: Physical Models and Numerical Methodsmentioning

confidence: 99%

“…In the present studies, ystart=0.1δinf and yend=δinf are adopted for the wall-modeled LES, where the turbulent inflow is treated by a recycling/rescaling method. 16 These parameters are chosen to make the RANS-to-LES transition occur in the inner log-law region of the turbulent boundary layer so that large structures in the outer region of the boundary layer and in the free shear layer are resolved by LES.…”

Section: Physical Models and Numerical Methodsmentioning

confidence: 99%

“…A recycling/rescaling approach is adopted to treat the turbulent inflow. 16

Figure 1.Schematic of computational domain for transverse jet. …”

Section: Physical Models and Numerical Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Simulations of combustion with normal and angled hydrogen injection in a cavity-based supersonic combustor

Proceedings of the Institution of Mechanical Engineers, Part G:

et al. 2013

Combustion characteristics in a supersonic combustor with normal and angled hydrogen injection upstream of a cavity flameholder are investigated numerically using a hybrid Reynolds-averaged Navier–Stokes/large eddy simulation method acting as a wall-modeled large eddy simulation. A turbulent incoming boundary layer with thickness of δinf = 2.5 mm is considered and a recycling/rescaling method is adopted to treat the unsteady inflow. Three injection angles, α = 30°, 60° and 90°, are considered. The results show that combustion efficiency increases with increasing injection angle since the fuel jet with larger injection angle tends to benefit more from the close coupling of flow, mixing and combustion. Moreover, it is found that the heat release distribution in the streamwise direction is more uniformly for larger injection angle than for lower injection angle, which tends to result in higher total pressure recovery in the far downstream regions for larger injection angle as uniformly-distributed heat release seems beneficial to reduce the total pressure loss for the present diffusion combustion.

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Mixing Characteristics of a Gaseous Jet in a Supersonic Crossflow

Jet in Supersonic Crossflow

Feng

2019