Selectively roughening inside surfaces of tubes increases the heat transfer capabilities, but minimizes the pressure drop. This technique is used to construct roughened test sections for hydrogen heat transfer studies

Carlson, L. W.

English

NASA Technical Reports Server

December 1966	 Brief 66l0610 
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. 
Selective Tube Roughening Increases Heat Transfer Capability 
Area To Be Roughened 
High Velocity Sand 
Carrying Gas —+ 
Inner Flowchannel  
Tube	'Deflective Ramp 
The problem:	 deflects the sand particles so they strike the surface 
To increase the heat transfer capability in tubes at 	 to be roughened at an oblique angle. 
selected locations. Increased surface roughness on the 	 Notes: 
inside of tubes increases the heat transfer capability, 	 1. This technique is being used to construct rough-
but it also increases undesirable pressure drop. 	 ened test sections for hydrogen heat transfer 
The solution:	 studies. 
Minimize the pressure drop by selectively roughen-	 2. Inquiries concerning this innovation may be di- 
rected to: ing only those areas which require higher heat trans-	 Technology Utilization Officer 
fer. Marshall Space Flight Center 
How it's done:	 Huntsville, Alabama 35812 
Selective roughening can be accomplished at speci- 	 Reference: B66-10610 
fled locations inside tubes by using an inner flow 	 Patent status: 
channel, flexible or rigid, for supplying a sand carry- 	 No patent action is contemplated by NASA. 
ing gas at high velocity. A ramp which covers ap-	 Source: L. W. Carlson 
proximately half the channel cross-sectional area	 (M-FS-599) 
Category 05 
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.
https://ntrs.nasa.gov/search.jsp?R=19660000608 2020-03-11T17:46:22+00:00Z


Selective tube roughening increases heat transfer capability

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