TESTING LONG-WAVELENGTH ACOUSTIC FLOWMETER CONCEPTS FOR FLUE GAS FLOWS

Published

June 22, 2012

Author(s)

Lee J. Gorny, Keith A. Gillis, Michael R. Moldover

Abstract

As a part of NIST’s program to standardize measurements of greenhouse gas emissions, we are developing a long-wavelength acoustic flowmeter (LWAF) for accurate, economical measurements of exhaust flows from coal-burning power plants. Measurements of the flue gas mass flowrate combined with the gas’s composition are used to determine the emitted CO2 and other by-products of combustion. Today, such measurements have uncertainties of 5% or more due to the large size of the flue-gas stacks and the flow’s non-uniform, unsteady, and swirling profile. A LWAF averages the spatial non-uniformities of the axial velocity over the entire cross section in a manner insensitive to flow distortions. In contrast, conventional techniques measure gas flow only at isolated points or averaged along chord across the stack. We constructed a 1:100 scale, calibrated flow facility for the initial development of a LWAF. In preliminary tests of three flow metering methods, uncertainties ranged from 1.4% to 4.9%, compared to our target uncertainty of 1%. We present the principle behind the LWAF, our design considerations, and the current performance of time and frequency-based approaches to metering, and describe technical challenges that must be overcome to use a LWAF at a full-scale power plant.

Proceedings Title

8th International Symposium on Fluid Flow Measurement

Conference Dates

June 18-22, 2012

Conference Location

Colorado Springs, CO

Pub Type

Conferences

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Keywords

flow meter, acoustic, long-wavelength, calibration, frequency response function, sound propagation, greenhouse gas, power plant, emissions, flue gas

Citation

Gorny, L. , Gillis, K. and Moldover, M. (2012), TESTING LONG-WAVELENGTH ACOUSTIC FLOWMETER CONCEPTS FOR FLUE GAS FLOWS, 8th International Symposium on Fluid Flow Measurement , Colorado Springs, CO, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=911460 (Accessed October 2, 2025)