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首页> 美国卫生研究院文献>Journal of Research of the National Institute of Standards and Technology >Sealed Gravitational Capillary Viscometry of Dimethyl Ether and Two Next-Generation Alternative Refrigerants
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Sealed Gravitational Capillary Viscometry of Dimethyl Ether and Two Next-Generation Alternative Refrigerants

机译：二甲醚和两种下一代替代制冷剂的密封重力毛细管粘度法

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摘要

The viscosities of dimethyl ether (DME, C2H6O) and of the fluorinated propene isomers 2,3,3,3-tetrafluoroprop-1-ene (R1234yf, C3H2F4) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) were measured in a combined temperature range from 242 K to 350 K at saturated liquid conditions. The instrument was a sealed gravitational capillary viscometer developed at NIST for volatile liquids. Calibration and adjustment of the instrument constant were conducted with n-pentane. The repeatability of the measurements was found to be approximately 1.5 %, leading to a temperature-dependent estimated combined standard uncertainty of the experimental data between 5.7 % at 242 K for dimethyl ether and 2.6 % at 340 K for R1234yf. The measurements were supplemented by ab initio calculations of the molecular size, shape, and charge distributions of the measured compounds. The viscosity results for dimethyl ether were compared with literature data. One other data set measured with a sealed capillary viscometer and exceeding the present results by up to 7 % could be reconciled by applying the vapor buoyancy correction. Then, all data agreed within the estimated uncertainty of the present results. Viscosities for the fluorinated propene isomers deviate up to 4 % from values predicted with the NIST extended corresponding-states model. The viscosities of the two isomers do not scale with their dipole moments. While the measured viscosity of R1234ze(E) with the lower dipole moment is close to that of R134a, the refrigerant to be replaced, that of R1234yf with the higher dipole moment is up to 25 % lower. The viscosity of dimethyl ether is compared with those of water and methanol.
机译：二甲醚（DME，C2H6O）和氟化丙烯异构体2,3,3,3-四氟丙烯-1-烯（R1234yf，C3H2F4）和反式1,3,3,3-四氟丙烯（R1234ze（E ））在饱和液体条件下在242 K至350 K的组合温度范围内进行测量。该仪器是NIST开发的用于挥发性液体的密封重力毛细管粘度计。用正戊烷进行仪器常数的校准和调整。发现测量的可重复性约为1.5％，从而导致实验数据的温度相关的估计组合标准不确定性介于242 K（对于二甲醚为5.7％）和340 K对于R1234yf为2.6％之间。通过从头开始计算所测化合物的分子大小，形状和电荷分布，可以补充这些测量结果。将二甲醚的粘度结果与文献数据进行了比较。可以通过应用蒸汽浮力校正来对用密封毛细管粘度计测得的另一组数据超出当前结果最多达7％。然后，所有数据均在当前结果的估计不确定性范围内达成一致。氟化丙烯异构体的粘度与NIST扩展对应状态模型预测的值相差高达4％。两种异构体的粘度不随其偶极矩成比例。虽然偶极矩较低的R1234ze（E）的测量粘度接近R134a，但要更换的制冷剂，偶极矩较高的R1234yf的粘度却降低了25％。将二甲醚的粘度与水和甲醇的粘度进行比较。

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