LES modeling of duo-model scramjet by dynamic zone flamelet model

Author(s):  
Zheng Zhang ◽  
Wei Yao ◽  
Wei Zhao
Keyword(s):  
Author(s):  
Masoud Darbandi ◽  
Majid Ghafourizadeh ◽  
Gerry E. Schneider

A hybrid finite-element-volume FEV method is extended to simulate turbulent non-premixed propane air preheated flame in a minichannel. We use a detailed kinetics scheme, i.e. GRI mechanism 3.0, and the flamelet model to perform the combustion modeling. The turbulence-chemistry interaction is taken into account in this flamelet modeling using presumed shape probability density functions PDFs. Considering an upwind-biased physics for the current reacting flow, we implement the physical influence upwinding scheme PIS to estimate the cell-face mixture fraction variance in this study. To close the turbulence closure, we employ the two-equation standard κ-ε turbulence model incorporated with suitable wall functions. Supposing an optically thin limit, it needs to take into account radiation effects of the most important radiating species in the current modeling. Despite facing with so many flame instabilities in such small size configuration, the current method performs suitably with proper convergence, and the encountered instabilities are damped out automatically. Comparing with the experimental measurements, the current extended method accurately predicts the flame structure in the minichannel configuration.


Author(s):  
Tomoya Murota ◽  
Masaya Ohtsuka

To analyze combustion oscillation in the premixed combustor, a large-eddy simulation program for premixed combustion flow was developed. The subgrid scale (SGS) model of eddy viscosity type for compressible turbulence (Speziale et al., 1988) was adopted to treat the SGS fluxes. The fractal flamelet model, which utilizes the fractal properties of the turbulent premixed flame to obtain the reaction rate, was developed. Premixed combustion without oscillation was analyzed to verify the present method. The computational results showed good accordance with experimental data (Rydén et al., 1993). The combustion oscillation of an “established buzz” type in the premixed combustor (Langhorne, 1988) was also analyzed. The present method succeeded in capturing the oscillation accurately. The detailed mechanism was investigated. The appearance of the non-heat release region, which is generated because the supply of the unburnt gas into the combustion zone stagnates, and its disappearance play an important role.


2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Yinli Xiao ◽  
Zupeng Wang ◽  
Zhengxin Lai ◽  
Wenyan Song

The development of high-performance aeroengine combustion chambers strongly depends on the accuracy and reliability of efficient numerical models. In the present work, a reacting solver with a steady laminar flamelet model and spray model has been developed in OpenFOAM and the solver details are presented. The solver is firstly validated by Sandia/ETH-Zurich flames. Furthermore, it is used to simulate nonpremixed kerosene/air spray combustion in an aeroengine combustion chamber with the RANS method. A comparison with available experimental data shows good agreement and validates the capability of the new developed solver in OpenFOAM.


1994 ◽  
Vol 96 (1-2) ◽  
pp. 104-120 ◽  
Author(s):  
Y BURIKO ◽  
V KUZNETSOV ◽  
D VOLKOV ◽  
S ZAITSEV ◽  
A URYVSKY

2006 ◽  
Vol 129 (1) ◽  
pp. 252-260 ◽  
Author(s):  
Song-Charng Kong ◽  
Hoojoong Kim ◽  
Rolf D. Reitz ◽  
Yongmo Kim

Diesel engine simulation results using two different combustion models are presented in this study, namely the representative interactive flamelet (RIF) model and the direct integration of computational fluid dynamics and CHEMKIN. Both models have been implemented into an improved version of the KIVA code. The KIVA/RIF model uses a single flamelet approach and also considers the effects of vaporization on turbulence-chemistry interactions. The KIVA/CHEMKIN model uses a direct integration approach that solves for the chemical reactions in each computational cell. The above two models are applied to simulate combustion and emissions in diesel engines with comparable results. Detailed comparisons of predicted heat release data and in-cylinder flows also indicate that both models predict very similar combustion characteristics. This is likely due to the fact that after ignition, combustion rates are mixing controlled rather than chemistry controlled under the diesel conditions studied.


2013 ◽  
Vol 57 (9-10) ◽  
pp. 2196-2206
Author(s):  
Greice S. Lorenzzetti ◽  
Álvaro L. de Bortoli ◽  
Lígia D.F. Marczak

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 705-716 ◽  
Author(s):  
Barbara Vidakovic ◽  
Milos Banjac

This paper, dealing with the problems of mathematical description of the tunnel fire development process with the use of experimental data, outlines the procedure of correction of the existing and obtaining of an improved CFD model package. The improved CFD model was developed on the basis of detailed analysis and comparison of experimental and numerical results, through consideration of the physical structure of all processes affecting combustion. During the analysis it was noticed that the existing CFD model in the part covering combustion based on the so-called steady laminar flamelet model, treats the combustion process almost as a direct correlation between the processes of mixing gasses and heat release rate. This potential deficiency has been overcome by correction of the model in the section defining boundary condition for the burning surface and by establishing a direct correlation between the measured value of the fuel mass change rate and the amount of heat released from burning surface. In this way a modification of complex stoichiometric combustion processes was avoided, while providing the model that better describes and predicts the course of events in this type of complex, anisotropic and turbulent flow of gases in the tunnel.


Author(s):  
David Sondak ◽  
Todd Oliver ◽  
Chris Simmons ◽  
Robert Moser
Keyword(s):  

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