Determining average flow speed in a scale model smokestack by measuring correlated noise through a long wavelength acoustic flow meter
As part of its Greenhouse Gas and Climate Science Measurements Program, the National Institute of Standards and Technology (NIST) has successfully developed long wavelength acoustic flowmeters (LWAFs) to measure the average flow speed, V, and the speed of sound, c, for a fluid passing through 1:100 scale test model of a coal burning power plant smokestack with standard measurement uncertainties of less than 1% and 0.1% respectively. This improves upon the estimated 5 20% standard measurement uncertainty for existing technologies. With this success NIST has constructed a 1:10 scale test model for further investigation. Current LWAF measurement techniques are reliant on a good signal to noise ratios (SNR) which may be problematic for the 1:10 scale test model since the amount of turbulence and difficulty generating high amplitude low frequency excitation signals at larger scales increases. Anticipating poorer SNRs for larger scale test models, NIST is investigating the use of the LWAF to correlate low fre.