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在Hagen-Poiseuille定律的基础上,利用双毛细管法,设计了一套适用于液态碳氢燃料高压低温粘度测量实验系统,测量压力:0.1~10 MPa,温度测量范围:233.35~313.75 K,扩展相对不确定度为:2.10%~5.08%(置信因子k=2)。实验在利用纯物质正己烷和质量比1:1正庚烷-正辛烷二元混合物对测量系统可靠性进行验证的基础上,测试了两种碳氢燃料A、B压力0.7、1.5、3和6 MPa,温度:233.55~313.65 K下的粘度值,结果表明:在相同压力下,两种燃料的粘度值随温度的增加而减小;在233.55~273.25 K附近,两种燃料粘度值随温度的变化率要大于273.25~313.65 K,表明低温区碳氢燃料A、B粘度受温度的影响比高温区大,且温度越低温度的影响程度越大;在233.55~273.25 K低温区范围内,燃料A粘度值受温度的影响程度要小于燃料B。实验中还发现,当温度接近231.25 K时,燃料B在毛细管中瞬间凝固,系统压力急剧升高,而燃料A在此温度下依然处于液态。在相同温度下,两种燃料的粘度值随着压力的增加稍有增大。此套高压低温粘度测量系统简单可靠,测量精度高,能够实现液态碳氢燃料高压低温粘度的在线测量。
Based on the Hagen-Poiseuille law, a set of high pressure and low temperature viscosity measurement experimental system for liquid hydrocarbon fuel was designed by double capillary method. The measurement pressure was 0.1 ~ 10 MPa, the temperature was measured in the range of 233.35 ~ 313.75 K, Uncertainty is: 2.10% ~ 5.08% (confidence factor k = 2). Based on the verification of the reliability of the measurement system by using n-hexane with mass ratio of 1: 1 and n-heptane-n-octane as binary mixture, two kinds of hydrocarbon fuels A and B were tested at pressures of 0.7, 1.5 and 3 And 6 MPa and temperature: 233.55 ~ 313.65 K respectively. The results show that the viscosity of the two fuels decreases with the increase of temperature under the same pressure. The viscosities of the two fuels change with the increase of temperature The change rate of temperature is greater than 273.25 ~ 313.65 K, indicating that the viscosity of hydrocarbon fuels A and B in the low temperature region is affected by the temperature more than the high temperature region, and the influence of the temperature is higher when the temperature is lower. In the range of 233.55 ~ 273.25 K , The fuel A viscosity value is less affected by the temperature than the fuel B. Experiments also found that when the temperature approached 231.25 K, the fuel B instantly solidified in the capillary, the system pressure increased sharply, while the fuel A at this temperature is still in the liquid state. At the same temperature, the viscosity of both fuels increases slightly with increasing pressure. This set of high-pressure low-temperature viscosity measurement system is simple and reliable, high accuracy, enabling liquid hydrocarbon fuel high-pressure low-temperature viscosity of the online measurement.