Accession Number : AD0717661

Title :   The Influence of Brazing on Very Compact Heat Exchanger Surfaces

Descriptive Note : Technical rept.

Corporate Author : STANFORD UNIV CA DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Shah, Ramesh K ; London, A L

PDF Url : AD0717661

Report Date : Nov 1970

Pagination or Media Count : 64

Abstract : Three geometrically similar offset rectangular plate-fin surfaces with area densities in the range from 900 to 2000 sq ft/cu ft were tested to establish the heat transfer, j-NR, and flow friction, f-N sub R, characteristics. The Reynolds number range was from 60 to 3000. One surface was unbrazed while the other two, because of a two-to-one difference in plate, fin and offset spacing dimensions, were characterized by different degrees of brazing 'roughness'. The test results reveal a relatively small effect of brazing on j-N sub R, but a significant influence on f-N sub R, with a 35 to 50 percent higher friction for the brazed surface. There is an 'area penalty' of 14 percent due to brazing associated with the complete coverage of the interface area at the brazed joints. The magnitude of this penalty depends on the geometry of the surface.

Descriptors :   *HEAT EXCHANGERS, BRAZING, HEAT TRANSFER, SURFACE PROPERTIES

Subject Categories : Air Condition, Heating, Lighting & Ventilating

Distribution Statement : APPROVED FOR PUBLIC RELEASE