Radiative Heat Flux Measurement Uncertainty.
Radiative Heat Flux Measurement Uncertainty.
(178 K)
Bryant, R. A.; Womeldorf, C. A.; Johnsson, E. L.;
Ohlemiller, T. J.
Fire and Materials, Vol. 27, No. 5, 209-222,
September/Ocotber 2003.
Keywords:
heat flux; uncertainty; heat transfer; equations
Abstract:
As part of an effort to characterize the uncertainties
associated with heat flux measurements in a fire
environment, an uncertainty analysis example was
performed using measurement data from a room corner
surface products test that followed the guidelines of
ISO 9705. Equations to model the heat transfer at the
surface of a Schmidt-Boelter (thermopile) type total
heat flux gauge were selected for use to calculate the
incident radiative flux from a total heat flux
measurement. The effects of the heat flux measurement
uncertainty sources were evaluated by conducting an
uncertainty propagation on the resulting equation for
incident radiation. For the model equations and the
example conditions selected, the free-stream temperature
estimate and the heat flux gauge calibration constant
were determined to be major uncertainty contributors.
The study demonstrates how to systematically identify
major sources of uncertainty for the purpose of reducing
total uncertainty and thereby enhancing experiment
design.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899