Combustion Heat-Release Effects on Supersonic Compressible Turbulent Boundary Layers

Gao, Zhenxun; Jiang, Chongwen; Pan, Shaowu; Lee, Chun‐Hian

doi:10.2514/1.j053585

Cited by 54 publications

(5 citation statements)

References 37 publications

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“…The governing Equations ( 1)-( 4) are solved using an in-house code ACANS, a finite difference CFD code developed by Gao et al [25]. The reliability of ACANS was verified by a variety of simulations, and the details of the code can be found in [26][27][28]. In the present numerical simulations, the inviscid flux vectors are discretized using the Roe scheme [29], and the monotone upstream-centered scheme for conservation laws method [30] is adopted to achieve second-order precision.…”

Section: Governing Equations and Numerical Methodsmentioning

confidence: 99%

Numerical Investigation on Mechanisms of MHD Heat Flux Mitigation in Hypersonic Flows

Zhou

Zhang²,

Gao

et al. 2022

Aerospace

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Numerical simulations of hypersonic magnetohydrodynamics (MHD) flow over a typical sphere–cone blunt body are carried out based on the assumption of a low magnetic Reynolds number. The effects of an external dipole magnetic field on the surface heat flux are analyzed in detail, and multiple mechanisms of the MHD heat flux mitigation are revealed systematically for the first time. The following is found: (1) The external magnetic field can effectively reduce the stagnation point heat flux, and the increase in the boundary layer thickness due to the effect of counter-flow Lorentz force, which is equivalent to adding an adverse pressure gradient, is the main reason. (2) In the head region of the blunt body, the relative surface heat flux shows a complex trend of rising and falling because there are two mechanisms which could produce the opposite effects on the surface heat flux. One is that the counter-flow Lorentz force results in an increase in the boundary layer thickness, and the other is that the Joule heating increases the static temperature behind the shock wave. (3) In the shoulder region of the blunt body, the Lorentz force component, normal to streamline, could change the flow direction of the fluid elements, causing the streamline to deviate from the wall or even separate, thus affecting the surface heat flux. (4) In the large area downstream of the blunt body, the surface heat flux could still be reduced by more than 30% due to the “upstream historical effect”.

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Section: Governing Equations and Numerical Methodsmentioning

confidence: 99%

Numerical Investigation on Mechanisms of MHD Heat Flux Mitigation in Hypersonic Flows

Zhou

Zhang²,

Gao

et al. 2022

Aerospace

Self Cite

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show abstract

“…All of the numerical simulations in present study were carried out using an in‐house finite‐difference program, ACANS, developed by the authors. The reliability of this program has been validated by a large number of numerical simulations 20‐22 . The governing equations and numerical methodology used in the ACANS program are introduced below.…”

Section: Governing Equations and Numerical Methodologymentioning

confidence: 99%

“…The reliability of this program has been validated by a large number of numerical simulations. [20][21][22] The governing equations and numerical methodology used in the ACANS program are introduced below.…”

Section: Governing Equations and Numerical Methodologymentioning

confidence: 99%

A correction for Reynolds‐averaged‐Navier–Stokes turbulence model under the effect of shock waves in hypersonic flows

Tian

Gao

Lee

2022

Numerical Methods in Fluids

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Studies on the unphysical increase of turbulent quantities for RANS simulation induced by shock waves in hypersonic flows are carried out. Numerical experiments on the hypersonic flow over a blunt body reveal that the phenomenon of unphysical increase of turbulent quantities across the detached shock wave is induced by the strain-rate-based production terms of the k-𝜔 and k-𝜔 SST turbulence models, which leads to the over-prediction of aerothermal prediction.While this phenomenon does not occur for Spalart-Allmaras (S-A) turbulence model because of its vorticity-based production term. In order to eliminate this unphysical phenomenon, and to maintain the accuracy of the original models for boundary layer and separation flows, a new correction method for the k-𝜔 and k-𝜔 SST models is proposed: by comparing the orders of magnitude between the strain-rate-based and vorticity-based production terms, the vorticity-based production term is used near the shock waves, while the original strain-rate-based production term is still used in other regions. Finally, the correction method is applied to turbulence and transition flows over blunt bodies, and the numerical results show that the correction method effectively eliminates the unphysical increase of turbulent quantities across shock waves and improves the accuracy of aerothermal and transition onset location prediction.

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“…1 for which an extensive set of comparison data in pure mixing and reacting conditions is available. Many authors have performed RANS studies of the geometry over the last three decades (40)(41)(42)(43)(44)(45)(46) . The test case is known (42,43) to be very sensitive to the the values of turbulent Prandtl (Pr t ) and Schmidt (Sc t ) numbers.…”

Section: Case 1: Burrows-kurkovmentioning

confidence: 99%

Characterisation of the eddy dissipation model for the analysis of hydrogen-fuelled scramjets

et al. 2019

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The eddy dissipation model (EDM) is analysed with respect to the ability to address the turbulence–combustion interaction process inside hydrogen-fuelled scramjet engines designed to operate at high Mach numbers (≈7–12). The aim is to identify the most appropriate strategy for the use of the model and the calibration of the modelling constants for future design purposes. To this end, three hydrogen-fuelled experimental scramjet configurations with different fuel injection approaches are studied numerically. The first case consists of parallel fuel injection and it is shown that relying on estimates of ignition delay from a 1D kinetics program can greatly improve the effectiveness of the EDM. This was achieved through a proposed zonal approach. The second case considers fuel injection behind a strut. Here the EDM predicts two reacting layers along the domain which is in agreement with experimental temperature profiles close to the point of injection but not the case any more at the downstream end of the test section. The first two scramjet test cases demonstrated that the kinetic limit, which can be applied to the EDM, does not improve the predictions in comparison to experimental data. The last case considered a transverse injection of hydrogen and the EDM approach provided overall good agreement with experimental pressure traces except in the vicinity of the injection location. The EDM appears to be a suitable tool for scramjet combustor analysis incorporating different fuel injection mechanisms with hydrogen. More specifically, the considered test cases demonstrate that the model provides reasonable predictions of pressure, velocity, temperature and composition.

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Combustion Heat-Release Effects on Supersonic Compressible Turbulent Boundary Layers

Cited by 54 publications

References 37 publications

Numerical Investigation on Mechanisms of MHD Heat Flux Mitigation in Hypersonic Flows

Numerical Investigation on Mechanisms of MHD Heat Flux Mitigation in Hypersonic Flows

A correction for Reynolds‐averaged‐Navier–Stokes turbulence model under the effect of shock waves in hypersonic flows

Characterisation of the eddy dissipation model for the analysis of hydrogen-fuelled scramjets

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