Particle grouping and agglomeration assisted by damper oscillation systems

Abstract

In this study, a novel system is proposed with the aim to promote particle agglomerations, and to assist the downstream process with better particle removal efficiency. In the batch process, the polluted air enclosed in a chamber is used to simulate the indoor stagnant air. It is found that the addition of a damper could speed up the reduction of particle number and the faster damper could lead to a greater reduction. The concentration of particle number in a chamber could be notably reduced by up to 73% after half an hour using two dampers with a cycle time of 0.5 s. It is found that the flow oscillations induced by the damper movement can facilitate particle collisions, and agglomerations, which also increase the particle deposition rate. On the other hand, a continuous flow is applied to simulate a reference process where particle laden air is continuously entering the chamber for downstream treatment. The use of a damper with a cycle time of 1 s has increased the particle removal efficiency of the downstream filters from 36% to 48%. By comparing the particle size distribution, the addition of dampers has been demonstrated to promote a shift towards larger particle sizes. Therefore, the results clearly demonstrate the efficacy of revolving dampers for reducing particle number, increasing filtration efficiency and reducing the risk associated with air pollution.