Coating Investigations on the Hyperboloid Flare

Abstract

Experiments on a Hyperboloid Flare model have been carried out in the HEG. The thermocouples on the model were coated with various metals to investigate surface catalysis. The pressure and heat transfer profiles indicate that the flow is uniform and repeatable for both conditions tested. Investigation into surface catalysis indicate that all materials tested for the coating resulted in lower heat transfer rates than theuncoated model. The reasons for this could be that the coatings are acting as an insulating layer or that there are water molecules on the coating inhibiting catalysis. Comparison of tests conducted with air and Nitrogen as the test gases, when the heat transfer is evaluated by forming a local Stanton number, suggest that there couldbe surface reactions occurring.