Rapid modeling of air flow through perforated tiles in a raised floor data center

Abstract

Generally, a porous jump model is used for rapid air flow simulations (without resolving the tile pore structure) through perforated tiles in data centers. The porous jump model only specifies a step pressure loss at the tile surface, without any influence on the flow field. However, in reality, the downstream flowfield is affected because of the momentum rise of air due to acceleration of air through the pores, and interaction of air jets emerging from the pores. The momentum rise could be captured by either directly resolving the tile pore structure, or simulated by specifying a momentum source above the tile surface. Specification of the momentum source obviates the need of resolving the tile pore geometry, and hence requires considerably lower computational effort. In previous investigations a momentum source in a specific region above the tile surface was imposed without providing a physical basis for its selection. The width and length of the momentum source region was the same as the tile dimensions. This model showed improved prediction with the experimental data, as well as with the model resolving the tile pore geometry. In the present investigation, we present a detailed analysis for obtaining the momentum source region dimensions and other associated input variables. The results from this rapid model are compared with the model resolving tile geometry and good agreement was obtained.