Experimental Heat Transfer To Blunt Axisymmetric Bodies Near The Limit Of Continuum Flow PDF Download

Measurements of average heat-transfer rates to blunt-nosed, axisymmetric, cold-walled bodies in a low-density, hypervelocity wind tunnel are given. Stream density was such that Reynolds and Knudsen numbers, based on nose radius and conditions immediately behind the bow shock, varied from 5 to 20 and 0.11 to 0.056, respectively. Thus, scaling on the basis of Knudsen number, these conditions may be said to simulate a body of one-foot nose radius at as much as 315,500-ft altitude. Heat-transfer rates are discussed in relation to the flow model successfully used in the past for studies of flows of high Reynolds number. In this context, it was found that measured heat-transfer rates to hemispheres below shock-layer Reynolds numbers of 20 exhibited a decreasing nondimensionalized rate relative to that estimated by methods appropriate to high Reynolds number conditions. This behavior is in accord with various applicable theories. Rates for the flat-faced bodies showed no tendency to decrease, and they were somewhat higher than predicted by theories for high Reynolds numbers.