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.

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.

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.

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.

Radiative Exchange Within a Two-Cavity Configuration With a Spectrally Selective Window

2004 ◽  
Vol 126 (2) ◽  
pp. 819-822 ◽  
Author(s):  
A. Z’Graggen ◽  
A. Steinfeld
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Reaction Chamber ◽  
Heat Transfer Analysis ◽  
Radiation Heat ◽  
Quartz Window ◽  
Spectrally Selective ◽  
Radiative Power ◽  
In Series ◽  
Cavity Configuration

Radiation heat transfer within a high-temperature solar thermochemical reactor that features two cavities in series is considered. The inner cavity is subjected to concentrated solar radiative power entering through a spectrally selective window positioned at its aperture. The outer cavity is a well-insulated enclosure containing the inner cavity. It serves as the reaction chamber and is subjected to thermal radiation emitted from the inner cavity. A radiation heat transfer analysis based on the radiosity enclosure theory is formulated and solved using the gray-band approximation for the selective (quartz) window. Energy absorption efficiencies and temperatures are determined and compared to the windowless case.

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 Three-dimensional radiation heat transfer analysis in a cylindrical gas reformer by the radiative heat ray method.

1989 ◽  
Vol 55 (514) ◽  
pp. 1724-1728
Author(s):  
Hiroshi TANIGUCHI ◽  
Kazuhiko KUDO ◽  
Naoki KUMAGAI ◽  
Kehui GUO ◽  
Takao KATAYAMA ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Heat Transfer Analysis ◽  
Radiation Heat ◽  
Ray Method

Swirl Flow Effects on Heat Release/Luminous Radiation in a Vortex Engine

2006 ◽  
Author(s):  
M. H. Saidi ◽  
A. Ghafourian ◽  
M. Kargar ◽  
M. Faisal
Keyword(s):  
Heat Transfer ◽  
Heat Release ◽  
Flow Rate ◽  
Equivalence Ratio ◽  
Radiation Heat Transfer ◽  
Axial Flow ◽  
Swirl Flow ◽  
Radiation Heat ◽  
Flow Effects ◽  
Luminous Radiation

Radiation heat transfer as an important phenomenon in combustion applications is an interesting subject for scientists and combustion researchers. Heat release and luminous radiative transfer phenomena in an experimental vortex engine are compared with 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. Mixtures of Propane and Butane with air enriched by oxygen are used as fuel and oxidizer. The effects of equivalence ratio and oxidizer mass flow rate are investigated as well.

On the Entropy Generation Formula of Radiation Heat Transfer Processes

2005 ◽  
Vol 128 (5) ◽  
pp. 504-506 ◽  
Author(s):  
L. H. Liu ◽  
S. X. Chu
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Discrete Ordinates ◽  
Local Entropy ◽  
Radiation Heat ◽  
Local Entropy Generation

Because thermal radiation is a long-range phenomenon, the local radiative heat flux is dependent on the temperature distribution of the entire enclosure under consideration and is not determined by the local temperature gradient. In the community of heat transfer, traditionally, the conduction-type formula of entropy generation rate is used to calculate the entropy generation rate of radiation heat transfer. In the present study, three counterexamples are considered. The discrete ordinates method is employed to solve the radiative transfer equation and then solve the radiative entropy generation rate. The results show that the traditional formulas of entropy generation rate for heat transfer generally cannot be used to calculate the local entropy generation rate of radiation heat transfer. Only in optically extremely thick situations, the traditional formula of entropy generation rate for heat transfer can be approximately used to calculate the local entropy generation rate of radiation heat transfer.

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