Calorimeter Measurement of Heat Transfer at Hypersonic Conditions

Abstract

An experimental method of determining heat-transfer rates up to 15,000 Btu/ft 2 sec on ballistic range models traveling at hypersonic Mach numbers is described. Measurements of the instantaneous melt location on the surface of a specially designed copper calorimeter are obtained from laser lighted photographs. Heating rates are inferred using a 2-D transient heat conduction analysis. Data generated using this technique are shown to be in agreement with exact numerical boundary-layer predictions. Sensitivity studies also show that heating rates can be measured within ± 10%. The procedure is useful for studying several energy transport mechanisms at hypersonic conditions. Nomenclature k = thermal conductivity, Btu/ft sec°R L = axial length of sleeve, ft q = incident heat-transfer rate, Btu/ft 2 sec TI = slab temperature, initial, °R T s = surface temperature, °R meit = axial length to melt location, ft a = thermal diffusivity, ft 2 /sec d = thickness of sleeve, ft 9 = exposure time, sec

A Fast-Response Calorimeter with Dynamic Corrections for Transient Heat Transfer Measurements

“…In such facilities, where the effective test time is on the order of milliseconds, the heat flux rate is derived from the transient temperature monitored at selected points on the model with fast response testing technology. Generally, the techniques can be divided into two categories; the first is based on heat flux sensors, such as resistance thermometers [5][6][7][8], thermocouples [9][10][11][12][13], and calorimeters [14][15][16][17], and the second is based on non-intrusive techniques such as temperature-sensitive paint [18,19] and thermography [20,21]. However, each technique has its own benefits and challenges.…”