Conference article

Modeling of the German National Standard for High Pressure Natural Gas Flow Metering in Modelica

Michael von der Heyde
Institut für Elektrische Energiesysteme und Automation, TUHH, Germany

Gerhard Schmitz
Institut für Thermofluiddynamik, TUHH, Germany

Bodo Mickan
Physikalisch-Technische Bundesanstalt, Germany

Download articlehttp://dx.doi.org/10.3384/ecp15118663

Published in: Proceedings of the 11th International Modelica Conference, Versailles, France, September 21-23, 2015

Linköping Electronic Conference Proceedings 118:71, s. 663-670

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Published: 2015-09-18

ISBN: 978-91-7685-955-1

ISSN: 1650-3686 (print), 1650-3740 (online)

Abstract

The German national metrological institute Physikalisch-Technische Bundesanstalt uses a High Pressure Piston Prover as the primary standard for calibration of high pressure natural gas flow meters. In the High Pressure Piston Prover the gas flow rate is determined by measuring the time a piston needs to displace a defined enclosed volume of gas. Fluctuating piston velocity during measurement can be a significant source of uncertainty if not considered in an appropriate way. A computational model was developed to investigate means for the reduction of this uncertainty. This model is presented in detail. It is written in Modelica. Validation of the model shows good compliance of the piston velocity in the model with measured data for certain volume flow rates. Reduction of the piston weight, variation of the start valve switching time and integration of a flow straightener were found to reduce the piston velocity fluctuations in the model significantly. Using Modelica as modeling language was a key for success, because Modelica is object-oriented and acausal. Furthermore the Modelica Standard Library has been utilized, which contains models from various physical domain such as thermodynamics, fluid flow and tribology.

Keywords

Modeling of Multi-Domain Physical Systems; High Pressure Piston Prover; High Pressure Natural Gas Flow Metering

References

Dassault Systemes. Dymola Dynamic Modeling Laboratory, 2014.

International Organization for Standardization. ISO 9300, 2005.

O. Kunz andW.Wagner. The GERG 2008 wide range equation of state for natural gases and other mixtures. Journal of Chemical Engineering, 2012.

O. Kunz, R. Klimeck, W. Wagner, and M. Jaeschke. The GERG 2004 wide range equation of state for natural gases and other mixtures. GERG Technical Monograph, 15, 2007.

B. Mickan, R. Kramer, H. Müller, V. Strunck, D. Vieth, and H.-M. Hinze. Highest precision for gas meter calibration worldwide: The high pressure gas calibration facility pigsar with optimized uncertainty. In International Gas Union Research Conference, 2008.

B. Mickan, R. Kramer, V. Strunck, and T. Dietz. Transient response of turbine flow meters during the application at a high pressure piston prover. In 15th Flow Measurement Conference (FLOMEKO), 2010.

Physikalisch- Technische Bundesanstalt. PTB mitteilungen, special issue volume 119 no.1, 2009.

Physikalisch Technische Bundesanstalt. Prüfschein der Rohrprüfstrecke, 1991.

G. Schmitz and A. Aschenbrenner. Experience with a piston prover as the new primary standard of the federal republic of germany in high pressure gas metering, 1990.

M. Uhrig, P. Schley, M. Jaeschke, D. Vieth, K. Altfeld, and I. Krajcin. High precision measurement and calibration technology as a basis for correct gas billing. In 23rd World Gas Conference, 2006.

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