Heat Transfer Retardation at Elevated Temperatures. Phase I. Analysis of Heat Transfer Retardation Configurations and Materials.

摘要

The heat transfer retardation characteristics at high temperatures of selected combinations of configurations and their materials of construction were analyzed, and lightweight retardation configurations have been identified for hot-gas applications with hot-side temperatures of 3000 F. The scope of the investigation was to use available materials and passive retardation techniques. Candidate structural configurations with promising heat transfer retardation characteristics were defined, candidate materials were identified, and combinations of these configuration types and their materials of construction were selected for analysis. A heat transfer model was formulated for the analyses of the retardation configurations selected for hot-gas applications and was used to estimate the retardation characteristics in terms of an overall thermal resistance and unit weight. Multi-layer configurations were selected with the thin outer layer of ceramic foam providing a hard and relatively smooth surface for flow path and structure, and the inner fibrous layer(s) providing the bulk of the thermal resistance. The overall lightweight combination consists of All-Alumina foam and dynaquartz (silica) fibrous insulation, because each material has the lowest value of the insulation performance factor in its category of materials. (Author)