Numerical Simulation of Jet Diffusion Flames With Radiative Heat Transfer Modeling

2005 ◽  
Author(s):  
Mario Baburic´ ◽  
Reinhard Tatschl ◽  
Neven Duic´

Beside appropriate turbulence and combustion modeling, the problem of an accurate prediction of turbulent diffusion flames usually requires accurate radiative heat transfer predictions as well. In this paper it is shown that the inclusion of radiation modeling into the overall numerical simulation is important if accurate temperature profiles are needed. Two different jet diffusion flame configurations are simulated in this work — a diluted hydrogen jet flame (80% H2 and 20% He by volume) [1–4], and a piloted methane jet diffusion flame (flame D) [5, 6]. The predictions are compared to experimental data. Radiation is modeled by a conservative discrete transfer radiation method (DTRM) [7, 8]. Turbulence is modeled by a classical k-ε and by a hybrid procedure, as proposed in [9]. Combustion modeling is based on the stationary laminar flamelet model (SLFM) [10], where the combustion/turbulence interaction is accomplished via the presumed β probability density function (β-PDF).

2014 ◽  
Vol 18 (6) ◽  
pp. 607-626 ◽  
Author(s):  
Jian Cai ◽  
Shenghui Lei ◽  
Adhiraj Dasgupta ◽  
Michael F. Modest ◽  
Daniel C. Haworth

Author(s):  
Kevin Torres Monclard ◽  
Olivier Gicquel ◽  
Ronan Vicquelin

Abstract The effect of soot radiation modeling, pressure, and level of soot volume fraction are investigated in two ethylene-air turbulent flames: a jet flame at atmospheric pressure studied at Sandia, and a confined pressurized flame studied at DLR. Both cases have previously been computed with large-eddy simulations coupled with thermal radiation. The present study aims at determining and analyzing the thermal radiation field for different models from these numerical results. A Monte-Carlo solver based on the Emission Reciprocity Method is used to solve the radiative transfer equation with detailed gas and soot properties in both configurations. The participating gases properties are described by an accurate narrowband ck model. Emission, absorption, and scattering from soot particles are accounted for. Two formulations of the soot refractive index are considered: a constant value and a wavelength formulation dependency. This is combined with different models for soot radiative properties: gray, Rayleigh theory, Rayleigh-Debye-Gans theory for fractal aggregates. The effects of soot radiative scattering is often neglected since their contribution is expected to be small. This contribution is determined quantitatively in different scenarios, showing great sensitivity to the soot particles morphology. For the same soot volume fraction, scattering from larger aggregates is found to modify the radiative heat transfer noticeably. Such a finding outlines the need for detailed information on soot particles. Finally, the role of soot volume fraction and pressure on radiative interactions between both solid and gaseous phases is investigated.


Author(s):  
Jian Cai ◽  
Shenghui Lei ◽  
Adhiraj Dasgupta ◽  
Michael F. Modest ◽  
Dan C. Haworth

Radiative heat transfer is studied numerically for high-pressure laminar H2-air jet diffusion flames, with pressure ranging from 1 to 30 bar. Water vapor is assumed to be the only radiatively participating species. A full spectrum k-distribution spectral model is used. Narrowband k-distributions of water vapor are calculated and databased from the HITEMP 2010 database, which claims to retain accuracy up to 4000K. The full-spectrum k-distributions are assembled from their narrowband counterparts to yield high accuracy with little additional computational cost. The radiative transfer equation (RTE) is solved using various spherical harmonics methods, such as P1, simplified P3 (SP3) and simplified P5 (SP5). The resulting partial differential equations as well as other transport equations in the laminar diffusion flames are discretized with the finite-volume method in OpenFOAM. Differential diffusion effects which are important in laminar hydrogen flames are also included in the scalar transport equations. It was found that peak flame temperature becomes less sensitive to radiation at higher pressure, and that radiation causes cooling in the downstream region. Differences between the three spherical harmonics RTE solver were found negligible below 5 bar.


1989 ◽  
Vol 55 (510) ◽  
pp. 523-528
Author(s):  
Masashi KATSUKI ◽  
Yukio MIZUTANI ◽  
Akihiro ANDO ◽  
Yoshihiro HATTORI ◽  
Yoichi JINJA ◽  
...  

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