The Influence of Brazing on Very Compact Heat Exchanger Surfaces

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.

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 1970
Accession Number
AD0717661

Entities

People

  • A. L. London
  • Ramesh K. Shah

Organizations

  • Stanford University

Tags

Communities of Interest

  • Energy and Power Technologies
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Air Flow
  • Brazed Joints
  • Fluid Flow
  • Friction
  • Geometry
  • Heat Transfer
  • Laminar Flow
  • Mechanical Engineering
  • New York
  • Physical Properties
  • Reynolds Number
  • Roughness
  • Steady Flow
  • Steady State
  • Surface Roughness
  • Surface Temperature
  • Test Methods

Readers

  • Combustion and Flow Dynamics.
  • Mathematics or Statistics
  • Metallurgy

Technology Areas

  • Space
  • Space - Hall-Effect Thruster