Numerical study of particulate turbulent flow to investigate recovery period in cleanrooms

Abstract

The cleanroom is a controlled space used in various industries such as electronics, and medical and military industries. One of the most important tests to evaluate the performance of the cleanroom is recovery test. Recovery test determines the time period during which a cleanroom returns to its designated cleanliness level after an instant or a period of deliberate or unintentional contamination. In this paper, a thorough investigation of recovery period has been implemented. In the study, air change rate and its pattern were investigated using the Eulerian and Lagrangian approaches as well as LES, DES, and k - ω SST turbulent models. Simulation results were evaluated through control volume analysis. Parameters such as the air change rate, the number of particles, and pressure and energy consumption in various radial and tangential angles of diffusers were studied. Results showed that radial angle had little positive and occasionally negative effects on recovery period. On the contrary, tangential angle improved decontamination rate; at maximum performance (β = 45°), it could reduce recovery period by as much as 25%, which in turn reduced energy consumption. In addition, the DES model provided the best and most coinciding answers among all turbulence models.