空气/液空在低温梯度磁场中的磁致扩散流动与氧氮分离

The applications of oxygen-enriched air is of great significance to energy saving and environmental protection. Under low temperature conditions, oxygen's magnetic susceptibility increases dramatically and air density aggrandizes greatly when air is liquified. Based on these physical properties, "Magnetic-Sieve" will produce a very effective separation of oxygen and nitrogen by placing the gradient magnetic field under low temperature. Therefore, usage of gradient magnetic field under low temperature to separation of oxygen and nitrogen may become a novel method with extremely low energy consumption and higher separation efficiency. In a gradient magnetic field, the separation of oxygen and nitrogen，especially in liquid air, is, in essence, a diffusive flow process of the gas/liquid in which there is strong intermolecular interaction. There is a strong coupling relationship between the magnetic field layout and the magnetizing force. This proposal project proposes a method, which utilize cascading magnet arrays to constitute "Magnetic-Sieve" array, and bonding the oxygen molecules in air/liquid air in the magnetic field space under lowtemper, to achieve oxygen enrichment. The interaction between magnet arrangement and the diffusive flow of intensive molecules will be studied experimentally and theoretically. The effects will be studied of the cascading magnet arrays' arrangement, the structure and size of the flow channels, and flow parameters of the air/liquid air on the flow and diffusion behaviors of air/liquid air in the gradient magnetic field, which will establish the theoretical and experimental basis for engineering applications.

富氧的应用对节约能源和保护环境都具有重要意义。利用低温条件下氧的体积磁化率快速增大和液化后空气密度大幅度提高的物理特性，将梯度磁场放置在低温环境下进行氧氮分离，会产生极有效的分离和富集效果。因此，利用梯度磁场在低温下进行氧氮分离可能成为一种全新的、运行能耗极小的获得富氧空气和提高分离效率的方法。梯度磁场下的氧氮分离，尤其是液态空气中的氧氮分离过程，实质上是分子间具有强相互作用的气体/液体在梯度磁场空间的扩散流动过程。磁场的布置形式与分子所受磁化力作用大小和作用时间之间具有强耦合关系。本申请项目提出利用磁体阵列构成"磁筛"阵列在低温下将空气/液空中的氧分子束缚在磁场空间内实现氧气富集的方法，实验和理论研究相结合，研究磁体布置与密集分子扩散流动间的相互影响关系与协同作用，获得磁体阵列结构、流道结构及尺寸、空气/液空流动参数等对磁致气/液流动/扩散行为的影响规律，为工程应用奠定理论和实验基础。

本项目以液氮温区的空气和液态空气为研究对象，研究了梯度磁场中顺/抗磁性气体/溶液组分的磁致流动行为和低温溶液中顺、抗磁性分子流动与扩散行为。（1）建立了梯度磁场对顺/抗磁性分子拦截能力的理论架构与表征方法，并运用这些定量表征指导磁场结构的规划与组织以及流动条件的选择。（2）研究并得到了磁致扩散流动与分子间粘滞力（也即顺/抗磁性分子受到不同方向磁场力作用形成的流速差异所产生的内部“摩擦力”）的关系。（3）实验研究了低温下液态空气中氧分子的磁致扩散流动行为和液态空气蒸发过程中的氧浓度的分布。（4）理论分析证明了磁场结构和拦截能力间之间存在强耦合关系，磁场强度、磁场梯度、梯度磁场的空间分布与磁体几何形状和空间结构相关，后者直接决定了气体/溶液流量确定时的流速和梯度磁场对氧分子的作用距离。（5）建立了磁场结构中氧氮混合气体和液体流动的控制模型和数值模拟计算方法，获得不同磁体结构和流动条件下氧氮分子的分布和氧富集量，从理论分析角度获得了氧氮混合气体和液体在磁筛流动模式下的流动行为规律。上述研究结果证明了将磁场力应用低温空气分离的可行性和较为可信的结果预测。