Supersonic Virtual Impactor for Separating Small Particles from Gases

本研究为分离小分子化合物提供了一种新的方法 (10>m。直径和更小）的颗粒。 在该方法中，气流被布置成作为射流流动， 并被迫撞击在圆锥形的撞击器上 面 圆锥面的尖端，只有一个很小的 小部分（称为少数流）实际上通过 光圈 少数粒子的平均尺寸 流量比通过的主流大得多 因为颗粒越大， 动量，不能谈判的转折，并遵循小 粒子进入光圈。 光圈连接到两个 同心管 外管具有实心壁，并且 内管在其端部附近的短距离内具有多孔壁 连接实心板。 气体在高压下供应到 管之间的环形空间，并通过 管的多孔部分进入孔后面的空间 形成逆流。 最后，将吸力施加在 内管，孔的下游。 的组合 通过多孔管的抽吸和流动产生了一个平面， 零流量，其分离从底部流出的气体， 内管和气体流出孔。 颗粒 穿过光圈的光线必须 逆流。 它们的动量足够大 可以让它们通过逆流， 在圆锥体上方重新加入主流。 通过调整 逆流压力，零流量平面可以移动， 这提供了对颗粒尺寸分布的一些控制 在下游端收集。 该研究将改进 这种设计通过使喷射气流冲击在 圆锥体以超音速运动。 超音速允许 大颗粒速度，并允许较小的颗粒 通过零流量平面并被收集。

This study develops a new method for the separation of small (10>m. in diameter and smaller) particles from a gas stream. In this method, the gas stream is arranged to flow as a jet, and forced to impinge upon a conically shaped impactor surface. The tip of the cone surface, and only a small fraction (termed the minority flow) actually moves through the aperture. The average size of the particles in the minority flow is much larger than that in the mainstream which passes over the particles because the larger particles, with greater momentum, cannot negotiate the turn and follow the small particles into the aperture. The aperture is joined to two concentric tubes. The outer tube has a solid wall, and the inner tube a porous wall for a short distance near its end joining the solid plate. Gas is supplied at high pressure to the annular space between the tubes, and passes through the porous part of the tube into the space behind the aperture creating a counterflow. Finally suction is applied in the inner tube, downstream from the aperture. The combination of suction and flow through the porous tube creates a plane of zero flow which separates gas flowing out of the bottom of the inner tube and gas flowing out of the aperture. Particles that have traveled through the aperture must progress against the counterflow. The ones large enough that their momentum can allow them to pass through the counterflow and eventually rejoin the majority flow over the cone. By adjusting the counterflow pressure the plane of zero flow can be moved, and this provides some control of the particle size distribution collected at the downstream end. The study will improve on this design by causing the jet gas stream impacting on the cone to move at supersonic speeds. Supersonic speeds allow large particle velocities, and permits smaller particles to pass through the plane of zero flow and be collected.