scholarly journals Inhomogeneous boundary-value problem of radiation heat transfer for a multicomponent medium

2020 ◽  
pp. 108-113
Author(s):  
A.Yu. Chebotarev ◽  
Keyword(s):  
Heat Transfer ◽  
Boundary Value Problem ◽  
Unique Solvability ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Boundary Value ◽  
Radiation Heat Transfer ◽  
Multicomponent Medium ◽  
Radiation Heat ◽  
Conjugation Conditions

An analysis of the solvability of an inhomogeneous boundary value problem for the equations of radiative heat transfer with the Fresnel conjugation conditions is presented. The nonlocal unique solvability of the boundary value problem is proved.

scholarly journals An algorithm for solving the boundary value problem of radiation heat transfer without boundary conditions for radiation intensity

2020 ◽  
pp. 114-122
Author(s):  
A.Yu. Chebotarev ◽  
◽  
P.R. Mesenev ◽  
Keyword(s):  
Heat Transfer ◽  
Boundary Value Problem ◽  
Boundary Conditions ◽  
Radiation Intensity ◽  
Radiation Transfer ◽  
Boundary Value ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Conductive Heat ◽  
Radiation Heat

An optimization algorithm for solving the boundary value problem for the stationary equations of radiation-conductive heat transfer in the three-dimensional region is presented in the framework of the $ P_1 $ - approximation of the radiation transfer equation. The analysis of the optimal control problem that approximates the boundary value problem where they are not defined boundary conditions for radiation intensity. Theoretical analysis is illustrated by numerical examples.

Anomalous Heat Diffusion in a Chain of Large Particles Through Radiative Heat Transfer

2019 ◽  
Author(s):  
B. K. Liu ◽  
J. M. Zhao ◽  
L. H. Liu
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Heat Diffusion ◽  
Far Field ◽  
Radiation Heat ◽  
Diffusive Regime ◽  
Particulate System ◽  
Anomalous Heat

Abstract Radiative heat transfer in particulate system has many applications in industry. Recently, the anomalous heat diffusion was reported for particulate system in near field thermal radiation heat transfer, and the existence of heat super-diffusive regimes was observed and the spread of heat can be described by Levy flight. In this work, attention is paid to investigate whether there is anomalous heat diffusion in far-field radiative heat transfer or not. Specifically, this study is focused on the radiative heat transport of a system, consisting of optically large particles, in the geometric optic range. Those particles are arranged in a linear chain surrounded by reflective walls and all particles are identical and equally spaced. The effect of the boundary type and particle surface emissivity on the heat diffusion is also investigated. The heat diffusion behavior in the far-field is studied based on Monte Carlo ray tracing method and the fractional diffusion equation in one dimension. The result indicates the existence of anomalous heat diffusion in the far-field by analyzing the asymptotic behavior of radiation distribution function (RDF). It’s shown that the distribution of RDF decays in power law and can be divided into two parts: for near the source particle, heat diffusive regime is super-diffusive (according to the analysis of fractional diffusion equation), while for far from the source particle, heat diffusive regime becomes sub-diffusive. Moreover, the kind of boundary type and particle wall emissivity have a significant influence on the heat diffusion of the far-field radiation heat transfer. This work will help the understanding of radiation heat transfer in particulate system in the far-field.

Analysis of Radiation Heat Transfer in an Enclosure Fire Including the Effect of Scattering

2005 ◽  
Author(s):  
W. W. Yuen ◽  
W. K. Chow
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Zone Model ◽  
Fire Growth ◽  
Radiation Heat ◽  
Fire Zone ◽  
Enclosure Fire ◽  
Radiative Exchange

The need for an accurate simulation of the radiative heat transfer in a fire zone model is demonstrated. Results show that the lack of an accurate model of the relevant physics of radiative heat transfer can lead to uncertainty which can severely limit the usefulness of a fire zone model. An accurate numerical model of radiative exchange including the effect of scattering, is applied to simulate the effect of radiative heat transfer on fire growth. Typical conservation equations in a fire zone models are used.

Investigation of Luminous/Nonluminous Radiation in a Vortex Engine

2007 ◽  
Author(s):  
M. H. Saidi ◽  
M. Kargar ◽  
A. Ghafourian
Keyword(s):  
Heat Transfer ◽  
Outer Surface ◽  
Direct Contact ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Axial Flow ◽  
Chamber Wall ◽  
Radiation Heat ◽  
Insulating Material ◽  
Quartz Window

Investigation of radiation heat transfer In vortex engine is an important and new phenomenon in combustion for scientists and combustion researchers. In this research some parts of the combustion chamber wall are insulated using Blanket as a high insulating material. The rate of radiative heat transfer to the chamber wall is calculated using temperature difference between inner and outer surface of chamber. In the experiments this parts are protected from direct contact with hot combustion media using quartz window. The luminous radiative transfer per volume of chamber and also volume of flame in a vortex engine are compared with that in a similar axial flow type engine. A detector sensitive to emission from C2* excited radically is utilized for the measurement of chemiluminescence emission at the centerline of chamber along all axial positions. The filtered photographs of flame are used to compare total C2* emission from flame.

scholarly journals Conjugate Heat Transfer Characteristics in a Highly Thermally Loaded Film Cooling Configuration with TBC in Syngas

Aerospace ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 16
Author(s):  
Jing Ren ◽  
Xueying Li ◽  
Hongde Jiang
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Transfer Model ◽  
Plate Temperature ◽  
Total Percentage ◽  
Barrier Coating

Future power equipment tends to take hydrogen or middle/low heat-value syngas as fuel for low emission. The heat transfer of a film-cooled turbine blade shall be influenced more by radiation. Its characteristic of conjugate heat transfer is studied experimentally and numerically in the paper by considering radiation heat transfer, multicomposition gas, and thermal barrier coating (TBC). The Weighted Sum of Gray Gases Spectral Model and the Discrete Transfer Model are utilized to solve the radiative heat transfer in the multicomposition field, while validated against the experimental data for the studied cases. It is shown that the plate temperature increases significantly when considering the radiation and the temperature gradient of the film-cooled plate becomes less significant. It is also shown that increasing percentage of steam in gas composition results in increased temperature on the film-cooled plate. The normalized temperature of the film-cooled plate decreases about 0.02, as the total percentage of steam in hot gas increases 7%. As for the TBC effect, it can smooth out the temperature distribution and insulate the heat to a greater extent when the radiative heat transfer becomes significant.

Discrete Ordinates Method for Transient Radiation Transfer in Cylindrical Enclosures

2003 ◽  
Author(s):  
Kyunghan Kim ◽  
Zhixiong Guo
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Radiative Heat ◽  
Radiation Transfer ◽  
Radiation Heat Transfer ◽  
Discrete Ordinates ◽  
Radiation Heat ◽  
Discrete Ordinates Method ◽  
Transient Radiation ◽  
Tissue Welding

The Discrete Ordinates Method (DOM) for solving transient radiation transfer equation in cylindrical coordinates is developed for radiation heat transfer in participating turbid media in pico-scale time domain. The application problems addressed here are laser tissue welding and soldering. The novelty of this study lies with the use of ultrashort laser pulses as the irradiation source. The characteristics of transient radiation heat transfer in ultrafast laser tissue welding and soldering are studied with the DOM developed. The temporal distribution of radiative energy inside the tissue cylinder as well as the radiative heat flux on the tissue surface is obtained. Comparisons are performed between laser welding without use of solder and laser soldering with use of solder. The use of solder is found to have highly concentrated radiation energy deposition in the solder-stained region and reduce the surface radiative heat flux accordingly. Comparisons of transient radiation heat transfer between the spatially square-variance and Gaussian-variance laser inputs and between the temporally Gaussian and skewed input profiles are also conducted.

Numerical analysis of radiative heat transfer in an inhomogeneous and non-isothermal combustion system considering H2O/CO2/CO and soot

2017 ◽  
Vol 27 (9) ◽  
pp. 1967-1985 ◽  
Author(s):  
Zhenhua Wang ◽  
Shikui Dong ◽  
Zhihong He ◽  
Lei Wang ◽  
Weihua Yang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Radiative Properties ◽  
Combustion System ◽  
Radiation Heat ◽  
Radiation Heat Flux ◽  
Participating Media ◽  
Content Type

Purpose H2O, CO2 and CO are three main species in combustion systems which have high volume fractions. In addition, soot has strong absorption in the infrared band. Thus, H2O, CO2, CO and soot may take important roles in radiative heat transfer. To provide calculations with high accuracy, all of the participating media should be considered non-gray media. Thus, the purpose of this paper is to study the effect of non-gray participating gases and soot on radiative heat transfer in an inhomogeneous and non-isothermal system. Design/methodology/approach To solve the radiative heat transfer, the fluid flow as well as the pressure, temperature and species distributions were first computed by FLUENT. The radiative properties of the participating media are calculated by the Statistical Narrow Band correlated K-distribution (SNBCK), which is based on the database of EM2C. The calculation of soot properties is based on the Mie scattering theory and Rayleigh theory. The radiative heat transfer is calculated by the discrete ordinate method (DOM). Findings Using SNBCK to calculate the radiative properties and DOM to calculate the radiative heat transfer, the influence of H2O, CO2, CO and soot on radiation heat flux to the wall in combustion system was studied. The results show that the global contribution of CO to the radiation heat flux on the wall in the kerosene furnace was about 2 per cent, but that it can reach up to 15 per cent in a solid fuel gasifier. The global contribution of soot to the radiation heat flux on the wall was 32 per cent. However, the scattering of soot has a tiny influence on radiation heat flux to the wall. Originality/value This is the first time H2O, CO2, CO and the scattering of soot were all considered simultaneously to study the radiation heat flux in combustion systems.

Eight Surfaces of Radiation Heat Transfer Network Model Development

2013 ◽  
Vol 391 ◽  
pp. 191-195 ◽  
Author(s):  
Ummi Kalthum Ibrahim ◽  
Ruzitah Mohd Salleh ◽  
W. Zhou
Keyword(s):  
Heat Transfer ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Model Development ◽  
Transfer Model ◽  
View Factor ◽  
Radiation Heat

This paper deals with the numerical solution for radiative heat transfer within a heated six wall surfaces baking oven, baking tin surface and bread surface. The radiation heat transfer model is constructed by adopting a radiation network representation analysis. The analysis applies view factor and radiosity in determining the radiation rates for each surface in the oven. The amount of radiation heat, q and temperature, T variables are equivalent to electric current and voltage, respectively. Finite difference method coupled with Gauss-Seidel iteration was selected to solve the equations involved in the analysis. Even though this method is tedious and intractable for multiple surfaces, but it would seem to be the most accurate and suitable approach for radiation analysis in the enclosure.

scholarly journals Heat Transfer Analysis of Viscous Incompressible Fluid by Combined Natural Convection and Radiation in an Open Cavity

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
M. Saleem ◽  
M. A. Hossain ◽  
Suvash C. Saha ◽  
Y. T. Gu
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Transfer Rate ◽  
Optical Thickness ◽  
Radiative Heat Transfer ◽  
Transfer Rate ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Open Cavity ◽  
Heat Transfer Analysis

The effect of radiation on natural convection of Newtonian fluid contained in an open cavity is investigated in this study. The governing partial differential equations are solved numerically using the Alternate Direct Implicit method together with the Successive Overrelaxation method. The study is focused on studying the flow pattern and the convective and radiative heat transfer rates are studied for different values of radiation parameters, namely, the optical thickness of the fluid, scattering albedo, and the Planck number. It was found that, in the optically thin limit, an increase in the optical thickness of the fluid raises the temperature and radiation heat transfer of the fluid. However, a further increase in the optical thickness decreases the radiative heat transfer rate due to increase in the energy level of the fluid, which ultimately reduces the total heat transfer rate within the fluid.

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