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Title:Radiative Heat Transfer for Emitting, Absorbing and Scattering Planar Media
Author(s):Skocypec, Russell Douglas
Department / Program:Mechanical Engineering
Discipline:Mechanical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Mechanical
Abstract:This analytical and experimental effort is directed toward understanding and predicting the radiative heat transfer in planar gas and particulate systems. The analysis models both nongray absorption of the gas phase by the exponential wide band model and the redirection of radiant energy by particulate scattering through the optical path length concept. The total hemispherical emittance for a single gas species in an isothermal planar layer with scattering particulate is developed. Exact results for a gas species of H(,2)O or CO(,2) are presented. A factor to incorporate scattering is presented to more easily utilize the analysis. The analysis is also applied to typical combustion processes. The results are given in terms of variables which are known or easily measured.
A solution technique is also developed which predicts the radiative heat transfer in a layer having any temperature distribution. The analysis is not restricted to heat transfer, however, and can be applied to radiative transfer for a medium having any internal source distribution. The solution technique predicts the transfer from any single source by solving the photon equation of transfer. Path length distributions are shown for a number of layers and source locations. The technique models isothermal layers very accurately by summing the contributions from a finite number of sources. By weighting the sources appropriately, a nonisothermal layer of particulate is modeled. Results indicate the effect of the cold boundary region on the flux leaving the layer.
An experimental system is developed to obtain a hot layer of gas and particulate which flows through a test section with cooled walls. Intrusive probes characterize the medium in terms of particle loading and temperature, and the normally-directed energy emitted from the one dimensional planar medium is measured radiometrically. Gas and particle flow are controlled. An optical system is designed to obtain spectral emittance data from the layer.
An experimental investigation is undertaken yielding emittance data from a layer containing carbon dioxide and nitrogen gases, and particulate of BNi-2. Emittance data is presented and exhibits the effects of particulate scattering. An extension of the 4.3 micron carbon dioxide band wings due to scattering is noted. Emittance data for both pure gas and gas and particulate media are compared to analytical predictions.
Issue Date:1985
Description:485 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.
Other Identifier(s):(UMI)AAI8511674
Date Available in IDEALS:2014-12-15
Date Deposited:1985

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