Computer program solves combined problem of heat transfer and material response for the stagnation region of blunt bodies experiencing melting and vaporizing or subliming ablation. Program contains formulas for the transitional regime to bridge between the free-molecule and continuum regimes

Matting, F. W.

English

NASA Technical Reports Server

November 1970
	 Brief 70-10615 
•	 NASA TECH BRIEF
	
141 
NASA Tech Briefs announce new technology derived from the U.S. space program. Thea are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technièal Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Analysis of Surface Ablation of Noncharring Materials 
The problem: conditions for the ablating material can be those for a 
The development of heat shields for space vehicles heat shield, or the aerodynamic base heating for an 
and long-range missiles has stimulated an increased object can be accounted for. The ablating material can 
effort	 to	 understand	 the process of ablation.	 This be a type that melts and/or vaporizes, sublimes, or 
intensified study is contributing to the understanding undergoes a surface chemical reaction in the ablation 
of natural ablative phenomena that occur when extra- process. The various material properties and the ex-
terrestrial bodies enter the Earth's atmosphere. Abla- ternal flow conditions can be input to the program 
tion data obtained in the laboratory, in arc-jet wind arbitrarily	 so	 that	 a	 variety	 of	 ablation	 research 
tunnels for, example, do not duplicate in any single problems can be studied. 
experiment all the conditions of entry flights; hence, Notes: 
there is a need for analytical methods of predicting 1. This program is written in FORTRAN IV for use 
and explaining the ablative phenomena. on the IBM 7094 computer. 
The solution: 2. Inquiries may be made to: 
A computer program which solves the combined COSMIC 
problem of heat transfer and material response for the Barrow Hall 
stagnation region of blunt bodies experiencing melting University of Georgia 
and vaporizing or subliming ablation. Athens, Georgia 30601 
How it's done:	 . Reference:	 B70-10615 
A number of well established equations are used by 3. The	 following documentation	 may be obtained 
the program; however, some of the features and equa- from: 
tions are new. The program takes into account the fact Clearinghouse for Scientific 
that entry bodies initially fly in the free-molecule re- and Technical Information 
gime, then in a transitional regime, and finally in the Springfield, Virginia 22151 
continuum regime of gas dynamics. The program con- Single document price $3.00 
tains formulas for the transitional regime to bridge (or microfiche $0.65) 
between the free-molecule and continuum regimes; 
these formulas have been rationally derived from sim- Reference: 
pIe models and are believed to fill an important gap in NASA-TN-D-3758 (N67-12779), Analysis of 
previous analyses of small objects entering a planetary Surface	 Ablation	 of Noncharring Materials 
atmosphere. with	 Description	 of Associated	 Computer 
Several options are available to the user. Internal Program 
radiation in the body is accounted for, or the body can 
be assumed to be opaque. Flight cases as well as wind- Source:	 F. W. Matting 
tunnel cases can be calculated; the flight cases can Ames Research Center 
be applied to any planet, provided certain character- (A RC- 10223) 
istics of the atmosphere are known. The rear boundary Category 09
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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Analysis of surface ablation of noncharring materials

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