Masters Theses


"The problem of radiative heat transfer from a spherical layer of absorbing-emitting gas has been studied. First, the medium is assumed to be gray and then nongray. A thorough survey of literature from fields other than heat transfer, such as astrophysics and neutron transport has been made to stimulate further interest in this important area. To gain some insight into the effect of various parameters on the heat transfer, simple physical situations involving isothermal medium are considered. Comparison of the results obtained for the flux from the spherical and planar layers reveal that the curvature becomes increasingly important as the inner to outer optical radii ratio decreases. The study of a particular nonisothermal case shows that the temperature variations are important and cannot be neglected. In the study of the nongray problem, a simplified rectangular model for the spectral absorption coefficient is first considered. The expressions developed for the simplified rectangular model turns out to be similar to the expressions for the gray analysis. With a small amount of additional computational time one can obtain the results for the simplified rectangular model. Carbon monoxide example is studied in order to illustrate how the rectangular model can be used to analyze radiative heat transfer in a nongray gas. The results of this example reveals that the influence of the 'windows' is quite profound, thus exposing the limitations of the gray analysis. In order to determine the effect of line or band shape on the radiative transfer, five different models for the absorption coefficient representing the rectangular, triangular, Doppler, exponential and Lorentz profiles are considered. The results obtained for the dimensionless flux reveal that the rectangular profile has the smallest numerical value of all the profiles. The effect of the "wings" of the Doppler, exponential and Lorentz profiles is evident only for large values of optical thickness. The limiting cases of the functions on which the expressions for the local radiative flux (both from gray and nongray medium) depends are also studied. All the results (except for carbon monoxide example) reported graphically as well as in tabular form in this study are obtained using double precision"--Abstract, pages ii-iii.


Crosbie, A. L. (Alfred L.)

Committee Member(s)

Armaly, B. F. (Bassem F.)
Joiner, James W., 1931-2013


Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering


University of Missouri--Rolla

Publication Date



xv, 173 pages


© 1971 Hakimuddin Kalimuddin Khalil, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Heat -- Transmission
Radiative transfer
Heat -- Radiation and absorption

Thesis Number

T 2659

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