A simplified CFD model for the radial blower

Detailed level Computational Fluid Dynamics (CFD) models for fans and radial blowers involve information about blade geometry, flow angles, blade rotational speed, and flow approach velocities. Accurate simulations of such models require large numbers of mesh points which is beyond the allocated time and available resources for engineering design cycles. When dealing with system or board level thermal analysis, where a fan or a blower is among many components to be modeled, a "macro" representation of a fan or a blower is preferred. A "macro" model for a fan is a plane surface that induces pressure across as the flow passes through it. The pressure-airflow relationship is taken from the fan curve provided by the fan manufacturer. A "macro" model for a radial blower is more involved because of the 90° flow turn inside the blowers housing and induced flow swirl caused by impeller blades. The need to capture the flow turn and induced swirl becomes more pronounced when simulating multiple interacting blowers inside a blower tray. In this paper, a systematic approach is presented to design the blower macro from the existing fan model. Icepak CFD results for the blower tray have been analyzed and compared with the experiments conducted at Applied Thermal Technologies Laboratory. Typical use of a three-fan blower tray in a system representing telecommunication applications is also presented.