Case Studies: Case 4 Use of Tiles of Varying Percent Open Area of Perforated Tiles Previous examples show that when CRAC units feed a long row of perfortaed tiles, the distribution of airflow rates is very nonuniform. One method of reducing the flow nonuniformity is to use perforated tiles of varying open area to counteract the variation in the pressure below the raised floor. A possible layout is shown in the following figure. The open area is largest for the tiles near the CRAC units and smallest for the tiles in the middle.   The flow distribution through the perforated tiles is shown in the following figure. The horizontal air velocity decreases and the pressure increases as one moves away from the CRAC units towards the center. The resistance to flow through a perforated tile is inversely proportional to its open area. Thus, by using tiles of decreasing percentage open area, the resistance to flow through them increases with distance from the CRAC units. This counterbalances the increase in the pressure below the raised floor. Therefore, the resulting tile flow distribution exhibits less nonuniformity than that in Case Study 1. Next Case Study Previous Case Study   [Home] [COMPACT] [MacroFlow Electronic] [MacroFlow General] [TileFlow] [News] [Contact Us] [Jobs] [Services]