ASTM International

Standard Test Method for Measuring Heat Transfer Rate Using a Thin-Skin Calorimeter
 N E459

Annotation

This test method covers the design and use of a thin metallic calorimeter for measuring heat transfer rate (also called heat flux). Thermocouples are attached to the unexposed surface of the calorimeter. A one-dimensional heat flow analysis is used for calculating the heat transfer rate from the temperature measurements. Applications include aerodynamic heating, laser and radiation power measurements, and fire safety testing.

Advantages:

Simplicity of Construction—The calorimeter may be constructed from a number of materials. The size and shape can often be made to match the actual application. Thermocouples may be attached to the metal by spot, electron beam, or laser welding.

Heat transfer rate distributions may be obtained if metals with low thermal conductivity, such as some stainless steels, are used.

The calorimeters can be fabricated with smooth surfaces, without insulators or plugs and the attendant temperature discontinuities, to provide more realistic flow conditions for aerodynamic heating measurements.

The calorimeters described in this test method are relatively inexpensive. If necessary, they may be operated to burn-out to obtain heat transfer information.

Limitations:

At higher heat flux levels, short test times are necessary to ensure calorimeter survival.

For applications in wind tunnels or arc-jet facilities, the calorimeter must be operated at pressures and temperatures such that the thin-skin does not distort under pressure loads. Distortion of the surface will introduce measurement errors.