Relate NMR Relaxation Times of Pure Components and Mixtures with Viscosities and Diffusion through Application of Corresponding States

设计并构造了一种多功能核磁共振探针。该探头能够在-20至200℃的温度范围内，在高达600 atm的压力下进行低信号噪声自旋晶格弛豫和扩散系数测量。探针也被配置成在这些温度和压力下，可以在样品中建立汽液平衡。在不久的将来，该探针将用于测量13CO2中的松弛时间（T1）和自扩散系数作为温度和压力的函数。对这种重要流体唯一的T1测量是Smith和他的同事（1986年）测量的四个等值线。一些研究人员已经测量了探头可达到的温度范围内CO2的自扩散系数，但测量仅限于压力低于200 atm。在纯二氧化碳测量之后，将研究二氧化碳和正十六烷的混合物。然后，这些数据将与经典输运性质相关联。这种类型的相关性在混合物中仍然相对未被探索。在整个项目中还将尝试一个全局对应状态处理。核磁共振能提供有关物质各相分子运动的丰富信息。从松弛时间，可以研究旋转和平移运动。用自旋回波法测量的扩散系数为研究平移运动提供了一种手段。在过去的几年里，核磁共振成像已经成为研究多孔介质中流体流动的一种有价值的工具。该技术实用性的一个主要挑战在于将核磁共振测量值与传统的热力学和输运性质联系起来。其相互关系如图1所示。我们当前核磁共振程序的目的是进一步发展和量化核磁共振可测量值，传输性质和状态变量之间的一些关系。从这些关系的发展中受益匪浅的一个领域是核磁共振图像的解释和量化。核磁共振成像的实际应用需要将核磁共振数据与传统的工程分析联系起来。

A versatile NMR probe has been designed and constructed. This probe is capable of performing low signal to noise spin- lattice relaxation and diffusion coefficient measurements at pressures up to 600 atm over a temperature range of -20 to 200oC. The probe is also configured so that vapor liquid equilibrium can be established in the sample at these temperatures and pressures. In the immediate future the probe will be used to measure relaxation times (T1) and self diffusion coefficients in 13CO2 as a function of temperature and pressure. The only T1 measurements on this important fluid are the four isochores measured by Smith and coworkers (1986). Several investigators have measured the self- diffusion coefficient of CO2 over the temperature range accessible to the probe, but the measurements are confined to pressures less than 200 atm. After the pure CO2 measurements, mixtures of CO2 and n-hexadecane will be studied. This data will then be correlated with classical transport properties. This type of correlation remains relatively unexplored for mixtures. A global corresponding states treatment will also be attempted throughout this project. NMR can supply a wealth of information about the motions of molecules in all phases of matter. From the relaxation times, the rotational and translational motions may be investigated. The diffusion coefficients, measured by the spin-echo method, provide a means to investigate translational motions. In the past several years NMR imaging has been established as a valuable tool in the investigation of fluid flow in porous media. A major challenge in the usefulness of this technique lies in relating the NMR measurables to traditional thermodynamic and transport properties. The interrelationship is shown in Figure 1. The purpose of our current NMR program, is to further develop and quantify some of the relationships between NMR measurables, transport properties, and state variables. One area which would benefit greatly from the development of these relationships is the interpretation and quantification of NMR images. Practical use of NMR imaging requires a correlation to bridge the NMR data with traditional engineering analysis.