Measurement of Viscosity and Density of the Mixtures Nitrogen-Carbon Dioxide and Methane-Etane and of the Pure Fluids Carbon Dioxide and Ethane

该项目的目标是为二氧化碳和乙烷、二氧化碳/氮气和甲烷/乙烷的二元混合物以及甲烷/氮气/二氧化碳的三元混合物的粘度开发一套参考数据。再加上先前项目提供的数据，这将产生一个参考数据集，从而能够验证现有的和开发新的气相粘度模型。在该项目的第一阶段，用于测量密度和粘度的仪器进行了根本性的改进。对低密度粘度仪(NDVMA)的测量单元进行了改造，并对NDVMA和粘度/密度组合测量仪(VDMA)的测量结果提出了新的回归方法。这些措施为计划中的测量提供了一个大大改进的基础。通过这种方式，可以避免在较早的测量中发生的系统偏差，并且大大减少了调整设备所需的时间。已研制出一套用于商业上无法获得的已知组成的混合气体的重量法制备装置。对不同惰性气体的实验测量证明了改进后的装置的可操作性。根据拟议的工作时间表，该项目一期工程已完成了对低压二氧化碳的系统测量。第二个项目阶段旨在对乙烷、两种二元混合物和三元混合物进行系统测量。预期的测量计划是雄心勃勃的，但考虑到仪器的改进似乎是现实的。有了新的数据，将建立一个参考数据集，涵盖从253至473K的温度范围，压力最高可达20兆帕。

The goal of the project is to develop a set of reference data for the viscosity of the pure fluids carbon dioxide and ethane, the binary mixtures carbon dioxide / nitrogen and methane / ethane and for the ternary mixture methane / nitrogen / carbon dioxide. Together with data available from an earlier project, this will result in a reference data set, which enables the validation of existing and the development of new models for gas phase viscosities. In the first phase of the project the apparatuses used to measure density and viscosity were radically revised. The measuring cell of the low density viscosity apparatus (NDVMA) was reconstructed and for both the NDVMA and the combined viscosity/density measuring apparatus (VDMA) new ways to regress results were developed. These measures form a substantially improved basis for the planed measurements. Systematic deviations that occurred in earlier measurements can be avoided this way and the time required for adjusting the apparatuses has substantially been reduced. A set up for gravimetric preparation of commercially not available gas mixtures with well-known composition has been developed. Test measurements with different noble gases prove the operability of the revised apparatus. According to the proposed work schedule, systematic measurements for carbon dioxide at low pressure have been completed in the first phase of the project. The second project phase aims at systematic measurements for ethane, for the two binary mixtures and for the ternary mixture. The foreseen measuring program is ambitious, but it seems realistic taking the improvements of the apparatuses into account. With the new data, a reference data set will be established that covers the temperature range from 253 to 473 K at pressures up to 20 MPa.