1. Scope

1.1 This test method covers the measurement of the heat-transfer rate or the heat flux to the surface of a solid body (test sample) using the measured transient temperature rise of a thermocouple located at the null point of a calorimeter that is installed in the body and is configured to simulate a semi-infinite solid. By definition the null point is a unique position on the axial centerline of a disturbed body which experiences the same transient temperature history as that on the surface of a solid body in the absence of the physical disturbance (hole) for the same heat-flux input.

1.2 Null-point calorimeters have been used to measure high convective or radiant heat-transfer rates to bodies immersed in both flowing and static environments of air, nitrogen, carbon dioxide, helium, hydrogen, and mixtures of these and other gases. Flow velocities have ranged from zero (static) through subsonic to hypersonic, total flow enthalpies from 1.16 to greater than 4.65 x 10 ¹ MJ/kg (5 x 10 ² to greater than 2 x 10 ⁴ Btu/lb.), and body pressures from 10 ⁵ to greater than 1.5 x 10 ⁷ Pa (atmospheric to greater than 1.5 x 10 ² atm). Measured heat-transfer rates have ranged from 5.68 to 2.84 x 10 ² MW/m ² (5 x 10 ² to 2.5 10 ⁴ Btu/ft ² -sec).

1.3 The most common use of null-point calorimeters is to measure heat-transfer rates at the stagnation point of a solid body that is immersed in a high pressure, high enthalpy flowing gas stream, with the body axis usually oriented parallel to the flow axis (zero angle-of-attack). Use of null-point calorimeters at off-stagnation point locations and for angle-of-attack testing may pose special problems of calorimeter design and data interpretation.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

E422 Test Method for Measuring Heat Flux Using a Water-Cooled Calorimeter

E511 Test Method for Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux Transducer

Keywords

calorimeter; convective; heat flux; heat flux gage; null-point; radiative; transient temperature; Calorimeter--aerospace applications; Convective energy; Extreme heat transfer rates; Heat flux; Heating tests--aerospace materials; Heat transfer; Transient temperature;

ICS Code

ICS Number Code 17.200.10 (Heat. Calorimetry)

DOI: 10.1520/E0598-96R02

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