Data center rack analysis using detached eddy simulations

In this study, the secondary flow field and the recirculation zones inside the Cold aisle of a 3-Rack system are investigated using the detached eddy simulation (DES) consisting of the elliptic blended κ-ε model. The secondary flow fields inside the cold aisle can result in reduced air flow through the servers and ultimately, localized heating of the servers above the prescribed temperature limits. DES is selected for analysis as it incorporates both the Large Eddy Simulation (LES) in the near-wall region and Unsteady Reynold Averaged Navier-Stokes (URANS) simulation away from the wall. Hence, DES can resolve complex flow structures relatively better than LES, while using reduced computational resources. The distribution of turbulent kinetic energy (TKE) and mean velocity magnitudes inside the cold aisle are examined. We find that there are relatively lower inlet velocities near the bottom of the server rack, thereby causing inlet temperatures to rise. We believe that these results would be useful in designing better, more energy efficient cooling approaches.