Modified Body Force Model for Air Flow Through Perforated Floor Tiles in Data Centers

Abstract

Generally, porous jump (PJ) model is used for rapid air flow simulations (without resolving the tile pore structure) through perforated floor tiles in data centers. The PJ model only specifies a step pressure loss across the tile surface, without any influence on the flow field. However, in reality, the downstream flow field is affected because of the momentum rise of air due to acceleration through the pores, and interaction of jets emerging from the pores. The momentum rise could be captured by either directly resolving the tile pore structure (geometrical resolution (GR) model) or simulated by specifying a momentum source above the tile surface (modified body force (MBF) model). Note that specification of momentum source obviates the need of resolving the tile pore geometry and, hence, requires considerably low computational effort. In previous investigations, the momentum source was imposed in a region above the tile surface whose width and length were same as the tile dimensions with a preselected height. 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 an analysis for obtaining the momentum source region dimensions and other associated input variables so that the MBF model can be applied for general cases. The results from this MBF model were compared with the GR model and good agreement was obtained.