Air Flow Modeling and Analysis for Thermal Management in Functional Burn-In Systems

Functional burn-in testing has become one of the major benchmark testing for computer processors recently. In this study, the air flow modeling and simulation in functional burn-in systems have been conducted with multiple fans for convection dominated thermal enhancement. In the tray-level modeling, the duct tray with three mother boards and dual processors are constructed with the thermal head on top of the duct tray. Two tray fan configurations, the 3-fan tray and the 4-fan tray, are examined. In comparison, the 4-fan tray provides a more uniform flow across the card clusters at reduced levels of noise and system impedance at the same flowrate. In the rack level model, the exhausting flow capacity becomes a key factor for the flow optimization. The tray flow performance for the rack with 3-fan trays is greatly suppressed due to the use of a limited exhaust fan. In comparison, the tray flow performance for the rack with 4-fan trays is not affected significantly since its flowrate range match with the exhaust fan flow range. The design guidelines and recommendations at the rack level are also presented and discussed.