Approaches for improving airflow uniformity in unidirectional flow cleanrooms.

Airflow behavior inside a cleanroom with vertical unidirectional flow has been investigated. The design parameters, such as porosity and height of raised floor, width of clean room and inlet velocity profile, which affect the uniformity of air velocity distribution inside the cleanroom have been studied computationally. The Reynolds-averaged Navier-Stokes equations governing the flow are solved using a finite-volume code ST AR-CD. The standard k-e turbulence model has been used. Approaches for improving airflow uniformity have been proposed and quantitatively examined based on intensive case studies. The present results show that the uniformity increases along with the height of raised floor. Alternatively, better airflow uniformity can also be achieved through a proper allocation of floor porosity or by controlling the distribution of inlet velocity profile. Suggestions on how to design unidirectional cleanrooms with desired airflow uniformity under practical constraints have been given