Uncertainty evaluation and verification of the standard device for high pressure natural gas nozzles
In this paper,the results of the real flow calibration of the critical flow venturi nozzle stand-ard device of a natural gas verification station are analyzed,and three fitting methods of the outflow coef-ficient are discussed,which verifies the accuracy of the PTB formula under high Reynolds number.At the same time,the mathematical model of the device was established,and the extended uncertainty of the device was evaluated as 0.22％(k=2)by comprehensively considering the outflow coefficient,stag-nant pressure,stagnation temperature,molar mass and compression factor,and the uncertainty level of the standard device was verified by the measurement audit of the Chinese Institute of Metrology.
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万方数据
