检定介质温度、压力对流量计在线检定的影响

INFLUENCES OF MEDIUM TEMPERATURE AND PRESSURE ON ONLINE FLOWRATE MEASUREMENT OF FLOWMETERS

流量计的检定和校准是流量量值传递的重要环节,而从计量学意义上讲,在线实流检定是最具备准确性、一致性、溯源性和实验性等计量特性的检定方法,所以在线实流检定一直是研究的重点。天然气的在线实流检定一般用移动式流量标准装置对现场的流量计进行检定。通过研究发现,检定介质的温度、压力波动,是影响流量计的检定的重要因素,尤其在小流量点进行测试时,会产生不可忽略的测量误差。为此,通过数学模型,分析了检定介质的温度、压力波动对天然气流量计在线实流检定的影响,并提出了相应的解决办法,可为开展天然气流量计在线实流检定工作提供参考。

The examination and calibration of flowmeter are significant for the flowrate measurement. In terms of metrology, the online flowrate measurement is the most accurate measurement methods, which has high coherence and property in tracing to the source along with experimental property. Thus, the online flowrate measurement has been attached with importance in research works. The portable flowrate standard facilities are used for the online flowrate measurement in the working place. The experiment results show that the temperature of medium and the pressure fluctuation are key factors affecting the measurement operation of flowmeter. Especially for testing points with low flowrate, the measurement errors are inevitable. The influences on the online flowrate measurement caused by the temperature of medium and pressure fluctuation were analyzed via mathematical models. Relevant solutions were put forward, which may provide references for carrying out online flowrate measurement for natural gas.