Cold Aisle Air Distribution in a Raised Floor Data Center With Heterogeneous Opposing Orientation Racks

In this paper we experimentally investigate the air flow distribution at the inlets of two opposing racks in a cold aisle. The racks have non uniform heat load and air flow requirements creating a heterogeneous data center environment. The Computer Room Air Conditioning (CRAC) unit fan speed is set to meet the air requirement of the high heat density rack. The effect of perforated tile air velocity on air distribution to both the racks is studied using particle image velocimetry (PIV) technique. PIV images are recorded at various rack heights corresponding to the locations of the servers in the rack. The PIV images recorded at various locations are stitched to construct a complete rack inlet air flow map. Three cases of rack air flow distributions are studied by varying the server work load and perforated tile flow rate. A significant change in the air distribution pattern is observed for the three cases investigated.