Report on the First-Generation NIST Convective Heat Flux Calibration Facility.
Report on the First-Generation NIST Convective Heat Flux
Calibration Facility.
(1689 K)
Holmberg, D. G.; Womeldorf, C. A.
NIST SP 971; NISTIR 6197; 17 p. August 2001.
NIST SP 971: "Collected Reports and Publications by
the National Institute of Standards and Technology on
Heat Flux Gage Calibration and Usage.", 2001.
Available from:
For More Information on NIST SP 971 visit: WEBSITE:
http://www.bfrl.nist.gov/866/heatflux/index.htm
Order number: PB99-150071
Keywords:
heat flux; calibration; convection; standards;
uncertainty
Abstract:
The National Institute of Standards and Technology has
developed a convective heat flux calibration facility to
allow evaluation of heat flux sensors. This facility is
a small wind tunnel that produces a two-dimensional
laminar boundary layer across a heated iso-thermal
copper plate. This facility has been developed to allow
convection calibration of heat flux sensors to
complement heat flux sensor calibrations presently
conducted using standard radiation methods, recognizing
that many sensors are used in mixed radiation and
convection environments. By extending calibration
capabilities to include a primarily convective
environment, direct comparisons of sensors in controlled
convective and radiative environments are possible.
This report describes the first-generation heated plate
design, analysis, and performance. The reference heat
flux on the plate is found from the electrical power
input to a guarded region of the plate to the side of
the sensor in spanwise uniform flow. Tests have
demonstrated a repeatability on the reference heat flux
of + 1.5%. A detailed uncertainty analysis of the
reference heat flux value is presented showing lateral
conduction to surrounding regions of the plate to be the
greatest source of uncertainty with plate surface
emissivity the only other significant source. The
calculated relative expanded uncertainty (95% level of
confidence) on the measured reference heat flux value is
+ 4.6%. The average reference heat flux from these
tests agrees with numerical predictions within 2%.
