Computer program determines the radiant flux to the base region of a real gas system with an axisymmetric geometry and any axisymmetric property distribution

De Soto, S.

Vok, C. A.

English

NASA Technical Reports Server

December 1968	 Brief 68-10447 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Plume Radiation Program 
The problem: 
To develop an analytical procedure for the predic-
tion of the radiative effects from rocket plumes such 
as those produced by the Rocketdyne F-I and J-2 
engines. 
The solution: 
A computer program which determines the radiant 
flux to the base region of a real gas system with an 
axisymmetric geometry and any axisymmetric prop-
erty distribution. 
How it's done: 
The program provides for the radiation contribu-
tion from carbon dioxide, water vapor, and incandes-
cent carbon particles (it is not difficult to extend the 
program to include other radiating constituents). The 
radiative flux is determined by simultaneously ac-
counting for the emission, interlayer absorption, and 
transmission of all of the radiating constituents. Dif-
ferences in the chemical composition of the plume 
"core", the afterburning mantle, and the surround-
ing atmosphere can be accomodated by the program. 
The present form of this program incorporates a 
"frozen equilibrium" chemical composition in the 
plume core along with a temperature and density dis-
tribution whièh varies as a function of the axial and 
radial positions. The program further provides for 
axial variations in temperature, pressure, and chemi-
cal composition in the afterburning mantle region, and 
fixed values of the pressure, temperature, and water 
vapor mol fraction for the surrounding atmosphere, 
if any exists. The core and afterburning mantle geome-
try and the distributions of temperature, density, pres-
sure, and chemical composition must be given as 
inputs to the computer program along with the nozzle 
geometry and the spectral absorption coefficients of 
all radiating constituents (as a function of tempera-
ture and wave number).
For an appropriate set of input values, the computer 
program predicts the local radiative flux to the base 
region of the vehicle. Further, the program simultan-
eously computes the configuration factor between the 
visible plume surface and an infinitesimal area element 
at the base of the vehicle. The occlusion effect of the 
nozzle is considered in determining the configuration 
factor. For cases in which it is valid to assume that 
the plume radiates as an opaque isothermal diffusely 
radiating surface, a "shell model" can be used based 
on this configuration factor. 
Notes: 
I. The program has been specifically applied to the 
case of a single rocket engine plume; however, the 
analytical techniques can be extended to other 
physical situations, for example, the analysis of 
radiation from a gas core nuclear reactor, multi-
ple plume rocket engine systems, and more gener-
ally, any axisymmetric radiating gas system. 
^. The program is written in Fortran IV for use on the 
IBM 7094 computer. 
. Inquiries concerning this program should be di-
rected to:
COSMIC 
Computer Center 
University of Georgia 
Athens, Georgia 30601 
Reference: B68-10447 
Patent status: 
No patent action is contemplated by NASA. 
Source: S. De Soto and C. A. Vok 
of North American Rockwell Corporation 
under contract to 
Marshall Space Flight Center 
(M FS- 13202) 
Category 06 
This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
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Plume radiation program

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