TY - JOUR AU - Kwiatkowski, Tomasz AU - Prusinski, Piotr AU - Zgorzelski, Dariusz AU - Kozioł, Sylwester PY - 2017 TI - Instability issues in the server room cooling system JF - Journal of Power Technologies; Vol 97 No 3 (2017) KW - HPC, computer cluster, efficient cooling, CFD N2 - Since 2009, the National Center for Nuclear Research in Poland has been constructing its own High Performance Computing (HPC) Centre under the name S´wierk Computing Centre (CIS´ ). Now, it is ready reaching its target—1 PFLOPS—in December 2015. However at the early operation stage, one of its major problems was the unstable work of the HPC cluster cooling system, resulting in increased maintenance costs. The main aim of this work is to thoroughly investigate the origin of the problem and to find the best solution for it based on results from a Computational Fluid Dynamics (CFD) analysis. The constructors suspected that the oscillations in the flow domain are caused by thermal flow stratification, but something else was proved. In this paper, a wide range of cases will be analyzed, covering different work regimes of the installation as well as various geometry modifications. Finally, certain improvement to the current design will be suggested by the CFD Analysis Group. UR - https://papers.itc.pw.edu.pl/index.php/JPT/article/view/677