Abstract Number: 79 Working Group: Instrumentation and Methods
Abstract Many collection devices have been used for the removal of micrometer sized droplets from air, such as air filter, mist eliminator, cyclone, and scrubber, etc. However, these devices cannot collect submicron sized droplets at a high efficiency because none of the mechanical collection mechanisms exert effectively for the removal of droplets in submicron range. In addition, the re-entrainment of collected droplets is of serious concern for these conventional collection devices. In this study, we introduced centrifugal force for the collection of submicron droplets by air filter, a new type of collection device; centrifugal filter. The basic idea of the centrifugal filter is to capture submicron droplets by rotating filter element. For example, if we attach a filter on the blades of a fan, the filter actively collect particles as a "bug collecting net", not passively waiting for the collision of bugs (particles) on the net (air filter). Moreover the use of centrifugal force is advantageous for the cleaning of air filter. If the centrifugal force acting on the particle deposits on the filter fibers is larger than the air drag, the deposited particles can be detached in the radial direction so that the re-entrained droplets no longer enter the filtered air. In the present work, we investigated the influence of rotation speed and radial thickness filter on the collection performance. In our estimation, the centrifugal filter consisting of 10 micro-meter fibers can collect 0.3 micro-meter particles at 50% collection efficiency when the filter outer radius is 40 mm, the rotation speed is 1000 rpm and the flow rate is 10 L/min. By introducing the centrifugal force to air filters, we can have one additional design parameter for air filter, which should broaden the application of air filters.