流体黏度对容积式流量计的性能影响

The Influence of fluid viscosity on the performance of volumetric flowmeter

提高原油交接流量计的准确度是客观公正地维护贸易双方合法经济利益的关键。目前在原油贸易交接计量中容积式流量计应用广泛,但是因其结构特点,容积式流量计在计量过程中存在漏失量,是计量误差的主要来源,而液体黏度是影响漏失量变化的主要因素。影响黏度变化的因素主要有压力因素和温度因素,而温度对于容积式流量计漏失量的影响是双方面的。通过在相同液体介质下,对同一台流量计进行3次测试试验,设置温度为试验唯一变量,测试结果显示流量计系数相差较大,进而说明不同温度下的流量计计量误差相差较大;此外,通过分析3次测试数据,其误差变化量与温度变化趋势不同,说明检定温度要符合介质物理特性,设置最适合的温度,以减小计量误差。

Improving the accuracy of crude oil transfer flowmeter is the key to maintain the legitimate economic interests of both sides objectively and justly.At present,positive volumetric flowmeter is widely used in crude oil trade metering.However,according to its structural characteristics,positive volumetric flowmeter has leakage in the metering process,which is the main source of measurement error,and the liquid viscosity is the main factor affecting the change of leakage.The main factors that affect the change of viscosity are pressure factors and temperature factors.However,the influence of temperature on the leakage of volumetric flowmeter is both sides.In the same liquid medium,the same flowmeter has been tested for 3 times,and the temperature has been set as the only variable of the test.The test results show that the flowmeter coefficient has a large difference,and then it shows that the flowmeter measurement error under different temperatures has a large difference.In addition,by analyzing the three test data,the error variation is different from the temperature variation trend,indicating that the verification temperature should be conformed to the physical characteristics of the medium and set the most suitable temperature to reduce the measurement error.