ASTM E511 – 07 Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux Transducer

Scope:

The goal of this test method is to make measuring a radiant heat flux easier. The sensor is used to detect heat fluxes from either mixed radiative-convective or pure convective sources, the uncertainty grows as the convective portion of the overall heat flux grows.

Procedure:

Most of the heat energy absorbed at the surface of the circular foil is routed radially to the heat sink when the sensing element was exposed to a heat source. Under steady-state circumstances, a parabolic temperature profile was created between the foil’s center and edge. The thermoelectric potential was created by the temperature differential between the center and the perimeter, and it varied in response to the absorbed heat flux.

Specimen size:

In an application where the copper heat-sink would reach 235°C (450°F) without cooling, a water-cooled transducer should be used.

Data:

The radiant heat flux is calculated using the equation:
q’ = E/K
q’ = absorbed heat flux
E= thermoelectric potential
K = sensitivity constant