HEAT TRANSFER IN STRUCTURAL HONEYCOMB COMPOSITES AT HIGH TEMPERATURES
Abstract
The use of superalloy and refractory alloy honeycomb composites for heat shield and structural components in re-entry vehicle applications is outlined followed by a detailed comparison between experimentally measured and analytically predicted thermal conductance values on superalloy honeycomb composites. The experimental thermal conductance determinations on L-605 cobalt alloy panels of variable geometry were made in high vacuum and air environments using a high temperature absolute thermal conductivity apparatus. Measurements were made over the range from 500 to 2000 F maintaining the temperature drop across the specimens below 200 F. Average precision of the results was plus or minus 7% while the accuracy was established to be plus or minus 10% based on initial calibration. The thermal conductances in air environment were between 60 and 100% above comparable values for the panels tested under vacuum conditions. Analysis of the results indicated that gaseous conduction and convection accounted for only a small fraction of the difference, the main effect being a large increase in the radiative contribution produced by increased emittance of the alloy through surface oxidation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1965
- Accession Number
- AD0481418
Entities
People
- Merrill L. Minges
Organizations
- Air Force Research Laboratory