Design and Uncertainty Analysis of a Second-Generation Convective Heat Flux Calibration Facility.
Design and Uncertainty Analysis of a Second-Generation
Convective Heat Flux Calibration Facility.
(642 K)
Holmberg, D. G.; Womeldorf, C. A.; Grosshandler, W. L.
NIST SP 971; August 2001.
NIST SP 971: "Collected Reports and Publications by the
National Institute of Standards and Technology on Heat
Flux Gage Calibration and Usage." AND Calibration,
Error Analysis, and Modeling of Heat Flux Sensors
Symposium. Proceedings. American Society of Mechanical
Engineers (ASME) Heat Transfer Division. Volume 4.
HTD-Vol. 364-4. November 14-19, 1999, Nashville, TN,
American Society of Mechanical Engineers, New York, NY,
65-70 pp, 2001.
Available from:
For More Information on NIST SP 971 visit: WEBSITE:
http://www.bfrl.nist.gov/866/heatflux/index.htm
Keywords:
calibrating; convection; heat flux; standards;
uncertainty
Abstract:
The National Institute of Standards and Technology has
developed a convective heat flux facility to allow
calibration of heat flux sensors. The facility consists
of a small wind tunnel that produces a two-dimensional
laminar boundary layer across a heated isothermal copper
plate. Sensors are mounted flush in the copper plate
alongside a reference to measure the heat leaving the
plate. Convective calibrations up to 5 kW/m2 are
possible. Sensor output is compared with the reference
value, and contrasted with a standard radiation
calibration. Recognizing that many sensors are used in
mixed radiation and convection environments, this
facility provides a unique opportunity to assess a
sensor's convective response. This report describes a
second-generation heated plate and provides an analysis
of the system uncertainty. Redundant references,
improved sensor heating and mounting, improved reference
isolation, and a minimized radiation component has
reduced the combined relative expanded uncertainty of
the reference to +2.5%. The benefits of an embedded
temperature sensor in the heat flux sensor are
describedThe facility is available for comparative
calibrations and for heat transfer studies by individual
researchers.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899