Engineering Initiation Award: Multiphase Flow Facility

叙述：了解流化床中固体循环、混合及其与传热的关系，对设计流化床燃烧器和化学反应器以及制定合理的放大程序至关重要。迄今为止，关于这个问题的系统的、定量的数据是有限的。为此，提出设计和建造放射性粒子跟踪装置，以研究常压流化床和加压流化床中的流体力学、混合、分离和传热。这种多功能的设备利用放射性示踪粒子，这些粒子在动力学上与要研究的粒子相同。示踪粒子的运动由一系列闪烁探测器跟踪，并由一台在线计算机进行分析。固体速度和任何特定种类颗粒的出现概率可以通过使用与它们的密度、大小和形状相匹配的示踪剂来获得。这些结果有望为流化床设计的结垢规律的制定做出贡献。拟议的研究将包括：(1)建造一个直径12英寸的床，(2)测量固体运动的平均和波动分量，(3)测量颗粒大小和密度偏析，(4)测量固体混合，(5)床流体力学对浸入表面或从浸入表面传热的影响，(6)测量加压流化床中固体的流体力学。

Narrative: Knowledge on solids circulation, mixing and their relation to heat transfer in a fluidized bed is of critical importance to the design of fluidized bed combustors and chemical reactors and to the development of a rational procedure for scale- up. To date systematic, quantitative data on the subject have been limited. Accordingly, it is proposed to design and build a radioactive particle tracking facility in order to study the hydrodynamics, mixing, segregation and heat transfer in atmospheric and pressurized fluidized beds. This versatile facility makes use of radioactive tracer particles which are dynamically identical to the particles to be studied. The motion of the tracer particles is tracked by an array of scintillation detectors and analyzed by an on-line computer. The solids velocity and occurrence probability of any particular species of particles can be obtained by using a tracer which matches their density, size, and shape. The results are expected to contribute to the formulation of the scaling laws for fluidized bed design. The proposed investigation will include: (1) Construction of a 12-inch diameter bed, (2) Measurements of mean and fluctuating components of solids motion, (3) Measurements of particle size and density segregation, (4) Measurements of solids mixing, (5) Influence of bed hydrodynamics on heat transfer to or from immersed surfaces and (6) Measurements of the hydrodynamics of solids in pressurized fluidized beds.