We report progress towards the goal of reducing the errors in industrial smokestack flow measurements to 1 % by replacing S-probes with calibrated 3-D probes (i.e., probes that measure 3 components of velocity). NIST calibrated a commercially-manufactured spherical probe and a prism probe at air speeds (5 m/s to 30 m/s) and pitch angles (20 to 20 °) using a yaw-nulling method similar to EPAs Method 2F. The expanded uncertainty for 3-D air speed measurements of both probes was near 1 % at a 95 % confidence level. Most of this uncertainty is attributed to the irreproducibility of the calibration measurements and the uncertainty of the NISTs laser Doppler anemometer air-speed standard. Thus, the 1 % goal might be possible; however, to obtain this low uncertainty, several significant uncertainties consistent with EPA Method 2F must be avoided. We document these uncertainties herein.
2018 International Symposium on Fluid Flow Measurement (ISFFM)
March 21-23, 2018
Querétaro, Mexico, -1
Method 2F, 5 hole probes, spherical probes, prism probes, stack flow testing, 3-D pitot probes, EPA RATA, Stack Emissions Flow Measurements, Yaw-nulling 3-D probe calibrations