Air Leakage Impact on System Thermal Behavior in 3U Chassis

This paper discussed the air leakage impact on a 3U system thermal behavior and provide reference to system that do not have independent cooling zone. The system is a 3U server with 2U compute bay and 1U storage bay. It is a high-density system to meet customers' requirements on both high-performance computing and storage. There is pressure difference between compute bay and storage bay with cable and busbar passthrough openings. The air leakage through these openings leads to thermal challenges in the compute bay and front HDD in storage bay. Both simulation models and experimental data showed the significant impact of air leakage. The compute bay air flow decreased 18% when leakage area open ratio increased from 10% to 80%. Wind tunnel test data also aligned with simulation data. Thermal validation data showed that the front HDD temperature improved 25C with design reduction in leakage area. With enhanced mechanical solution, the leakage can be significantly improved by 40.5% and 63.1% for different storage configuration.