TO-22-C009 - Flow Resistance Characteristics for Data Center CFD

Data-center-level CFD simulations require compact models of perforated tiles and other flow resistances that accurately model pressure drop. We discussthe physics of airflow through resistances and compare loss coefficients obtained from commonly used empirical (handbook) correlations, detailed CFDmodeling (using four commercial CFD codes), and experimental measurements (using two wind tunnels). Test resistances include square-holed perforatedplates with nominal open area ratios of 15%, 25%, 39%, and 56% and one commercial data-center tile of nominal 56% open area. CFD issignificantly more accurate than the correlations in predicting resistance characteristics with the added benefit of allowing the modeler to start only fromgeometry (e.g., CAD) data and precisely control the "experimental" conditions. We also propose a new and simple empirical correlation which fits themeasured data better than existing correlations for the perforated plates considered here.