The operating conditions or operating conditions of a flow meter directly affect its metering performance. The most direct effect of a change in operating pressure or temperature on a flow meter is the change in its metering cavity.
：其间接影响是被测介质粘度、密度等物性参数的变化，但间接影响可在修正物性影响时考虑。 1. Electromagnetic flowmeter : its indirect effect is the change of physical property parameters such as the viscosity and density of the measured medium, but the indirect effect can be considered when correcting the physical property effect. Due to the complexity of the structure and shape of the flow meter and the discreteness of the processing and assembly, it is almost impossible to use a calculation method to accurately modify its cavity with changes in operating conditions, and it is impossible to fit all flow meters based on test data. An empirical formula that meets accuracy requirements.
：对于容积流量计而言，在进行流量仪表的型式鉴定、样机试验或质检抽查时，自然吸气式发动机被改装为增压式发动机后，不管是采用废气涡轮增压器还是机械增压器，涡街流量计都会遇到进气温度高的问题，涡街流量计因为经过压缩后的空气温度肯定比未经过压缩的高。 2. Turbine flowmeter : For volumetric flowmeters, when performing type identification, prototype test or quality inspection of flow meters, the naturally aspirated engine is converted to a supercharged engine, regardless of whether the exhaust turbocharger is used. It is also a supercharger. Vortex flowmeters will encounter the problem of high intake air temperature. The compressed air temperature is definitely higher than that of uncompressed airflow meters. ，操作条件改变将引起其流通面积的变化，从而导致仪表系数的变化。 The intake air temperature of a naturally aspirated engine does not change much regardless of the state of the engine, whether it is installed in the air flow meter, or on the intake manifold or the air compartment not far from the throttle, it is different. Not big; For a speed turbine flowmeter , changing the operating conditions will cause a change in its flow area, which will cause a change in the meter coefficient. If the operating conditions of the flow meter can be the same or close to the actual use, the offline verification can meet the requirements. However, due to the complexity and variability of operating conditions, offline verification often cannot reproduce the actual operating conditions. Only online real-flow verification can solve the problem of high-accuracy flow measurement, otherwise additional errors must be considered.