Development of a high performance static air mixer with a short mixing distance

Abstract Air mixing in an air mixing chamber affects an air-conditioning system's performances. Low air mixing effectiveness is associated with several problems. In this study, modified statistical air mixing effectiveness is proposed. An experimental study and CFD (Computational fluid dynamics) simulation were conducted for the development of high performance static air mixer over a short mixing distance. Based on the analysis results for the conventional air mixing chamber and the bridge type air mixer, it was determined that development strategies can be set as openings for an outdoor air discharge were placed between the openings for a return air discharge. This extends the mixing distance of an outdoor air and a return air as long as possible. Several applications to the strategies have been examined. According to the results, a “Double inducing chamber/three slits on each side wall” showed the best air mixing performance among the cases examined. Air mixing effectiveness was 87% for 30% outdoor air, and pressure loss approximately 19 Pa. The performances were validated in the experiment. The best case scenario results showed a very short air mixing distance. Air mixing effectiveness reached a high level with an air mixing distance of 0.2, and an air mixing effectiveness of 71–87% as a percent outdoor air varies from 10% to 90%.