Supply Plenum and Airflow Uniformity in Cleanrooms

The uniformity of airflow distribution in a cleanroom has been studied as a function of supply plenum geometry. The flow uniformity is measured experimentally by means of a hot-wire anemometer mounted at the end of a mechanical arm attached to an X-Y table. In addition, a numerical simulation procedure has been developed to calculate the flow velocity below the ceiling filter by taking into account the influence of supply plenum geometry. In the specific system studied, the major cause of flow non-uniformity is the turning of the flow at the end of the supply plenum and the impingement of flow directly at the filter face. The numerical result shows that the flow non-uniformity can be decreased by increasing the size of the supply plenum or reducing the velocity of the airflow in the plenum.