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

Ladda ner artikelhttp://dx.doi.org/10.3384/ecp15118663

Ingår i: 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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Publicerad: 2015-09-18

ISBN: 978-91-7685-955-1

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


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.


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


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