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Applications of accurate isentropic exponent determination for fuel gas measurement

Pack, D.J., Edwards, T.J. and Fawcett, D. (1996) Applications of accurate isentropic exponent determination for fuel gas measurement. Journal of Engineering for Gas Turbines and Power, 118 (3). pp. 541-546.

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This paper discusses the determination and application of the isentropic exponent to the various thermodynamic processes found in a high-pressure natural gas transmission system. Increasing demands for more precise measurement of natural gas, coupled with the need for greater efficiency and accountability of transportation and processing operations, had led to our research and development efforts into the more precise measurement of gas flow, and the determination of gas thermodynamic properties including isentropic exponent. The isentropic exponent has many applications, some of which include: • the determination of the expansion factor ε, for calculation of flow using an orifice or venturi-type meter; • the volumetric efficiency in a reciprocating compressor; • the determination of the compression head for a centrifugal compressor; • the engine power required for the given conditions for a gas compressor; • the calculation of discharge temperatures for compressors; and • the direct measurement of gas density. As can be appreciated, the application of an incorrect value for the isentropic exponent represents an error in the parameter determined. For large volume gas flows, this can translate into a significant cost penalty.

Item Type: Journal Article
Murdoch Affiliation(s): School of Engineering
Publisher: American Society of Mechanical Engineers
Copyright: © 1996 by The American Society of Mechanical Engineers
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