Modeling blower flow characteristics and comparing to measurements

Thermal management for high performance electronic systems such as servers and I/O boxes has become increasingly challenging due to the ever growing demand for higher computing performance and packaging density. Proper modeling, design and characterization of the cooling system have become critical to the overall system performance, reliability and energy consumption. Air moving devices such as blowers (centrifugal fans) are key components of the air-cooled electronic systems. This paper focuses on the flow characteristics of blowers and the impact on the system air flow distribution. To capture the flow characteristics, different levels of numerical modeling methodology are considered using a commercially available tool. It is demonstrated that a simple compact model, typically used in system level models, is not sufficient to resolve the air flow distribution near the exhaust. A more detailed model which includes the actual geometry of the blower blades resolves the body forces using MRF and predicts the flow distribution with better agreement with measurement data. Comparing the different modeling methodologies for systems of different impedance characteristics, a general guideline is subsequently proposed.