RADIATIVE HEAT TRANSFER CALCULATION FOR PULVERIZED COAL COMBUSTION APPLICATION OF LORENZ-MIE THEORY

1986 ◽  
Author(s):  
D. Grouset ◽  
D. Rebuffat
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Coal Combustion ◽  
Radiative Heat ◽  
Mie Theory ◽  
Pulverized Coal ◽  
Pulverized Coal Combustion ◽  
Heat Transfer Calculation

Development of Radiative Heat Transfer Model for Pulverized Coal Combustion

2008 ◽  
Vol 34 (3) ◽  
pp. 344-350 ◽  
Author(s):  
Toshimitsu Asotani ◽  
Toru Yamashita ◽  
Hiroaki Tominaga ◽  
Yoshinori Itaya ◽  
Shigekatu Mori
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Coal Combustion ◽  
Radiative Heat ◽  
Heat Transfer Model ◽  
Pulverized Coal ◽  
Transfer Model ◽  
Pulverized Coal Combustion

Influence of Index of Refraction and Particle Size Distribution on Radiative Heat Transfer in a Pulverized Coal Combustion Furnace

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Robert Johansson ◽  
Tim Gronarz ◽  
Reinhold Kneer
Keyword(s):  
Heat Transfer ◽  
Particle Size ◽  
Radiative Heat Transfer ◽  
Coal Combustion ◽  
Radiative Heat ◽  
Pulverized Coal ◽  
Index Of Refraction ◽  
Pulverized Coal Combustion ◽  
Complex Index ◽  
Complex Index Of Refraction

In this work, the influence of the radiative properties of coal and ash particles on radiative heat transfer in combustion environments is investigated. Emphasis is placed on the impact on the impact of the complex index of refraction and the particle size on particle absorption and scattering efficiencies. Different data of the complex index of refraction available in the literature are compared, and their influence on predictions of the radiative wall flux and radiative source term in conditions relevant for pulverized coal combustion is investigated. The heat transfer calculations are performed with detailed spectral models. Particle radiative properties are obtained from Mie theory, and a narrow band model is applied for the gas radiation. The results show that, for the calculation of particle efficiencies, particle size is a more important parameter than the complex index of refraction. The influence of reported differences in the complex index of refraction of coal particles on radiative heat transfer is small for particle sizes and conditions of interest for pulverized coal combustion. For ash, the influence of variations in the literature data on the complex index of refraction is larger, here, differences between 10% and 40% are seen in the radiative source term and radiative heat fluxes to the walls. It is also shown that approximating a particle size distribution with a surface area weighted mean diameter, D32, for calculation of the particle efficiencies has a small influence on the radiative heat transfer.

Analysis of Radiative Heat Transfer Model for Pulverized Coal Combustion

2004 ◽  
Vol 2004 (0) ◽  
pp. 331-332
Author(s):  
Akinori GOTO ◽  
Hideto HAGIYA ◽  
Yoshio Morozumi ◽  
Hideyuki AOKI ◽  
Takatoshi MIURA
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Coal Combustion ◽  
Radiative Heat ◽  
Heat Transfer Model ◽  
Pulverized Coal ◽  
Transfer Model ◽  
Pulverized Coal Combustion

Modeling of Anisotropic Scattering of Thermal Radiation in Pulverized Coal Combustion

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Tim Gronarz ◽  
Robert Johansson ◽  
Reinhold Kneer
Keyword(s):  
Heat Transfer ◽  
Coal Combustion ◽  
Numerical Models ◽  
Mie Theory ◽  
Anisotropic Scattering ◽  
Forward Scattering ◽  
Pulverized Coal ◽  
Isotropic Scattering ◽  
Pulverized Coal Combustion ◽  
Model Based

In this work, the effect of applying different approximations for the scattering phase function on radiative heat transfer in pulverized coal combustion is investigated. Isotropic scattering, purely forward scattering, and a δ-Eddington approximation are compared with anisotropic scattering based on Mie theory calculations. To obtain suitable forward scattering factors for the δ-Eddington approximation, a calculation procedure based on Mie theory is introduced to obtain the forward scattering factors as a function of temperature, particle size, and size of the scattering angle. Also, an analytical expression for forward scattering factors is presented. The influence of the approximations on wall heat flux and radiative source term in a heat transfer calculation is compared for combustion chambers of varying size. Two numerical models are applied: A model based on the discrete transfer method (DTRM) representing the reference solution and a model based on the finite volume method (FVM) to also investigate the validity of the obtained results with a method often applied in commercial CFD programs. The results show that modeling scattering as purely forward or isotropic is not sufficient in coal combustion simulations. The influence of anisotropic scattering on heat transfer can be well described with a δ-Eddington approximation and properly calculated forward scattering factors. Results obtained with both numerical methods show good agreement and give the same tendencies for the applied scattering approximations.

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