Thermal design and solutions for handling heat loads in high-speed connectors for data centers
The rapid growth of data transmission and power density in high-speed interconnects such as OSFP (Octal Small Form-Factor Pluggable) and QSFP (Quad Small Form-Factor Pluggable) modules have made thermal management a critical design challenge. Although liquid cooling has emerged as a high-capacity alternative, its implementation at the connector level remains challenging due to system complexity, elevated cost, and potential reliability concerns. Consequently, this study focuses on enhancing air-cooled forced convection performance using computational fluid dynamics (CFD) based modeling and experimental validation. A detailed 3-D numerical model was developed in Ansys Icepak Classic 2023 to simulate conjugate heat transfer within high-speed connector assemblies under realistic airflow and thermal conditions. The model accounted for conduction, convection, and fan-driven pressure differences corresponding to 3 inWC (≈ 746.5 Pa) system airflow. Multiple configurations, varying dividing floor geometry (solid vs. perforated), heat-sink placement (top, bottom, and inter-module), and cage ventilation (standard vs. vented), were examined for both OSFP 2×1 and QSFP 1×1 architectures. Model validation against experimental measurements demonstrated excellent agreement, with an error margin below ±5%. The results revealed that introducing a perforated dividing floor enhanced inter-module airflow mixing, lowering hotspot temperatures by 3-4 °C, while adding a bottom heat sink achieved an additional 6-8 °C reduction and decreased junction-to-ambient thermal resistance by approximately 13%. Relocating the bottom heat sink to an inter-module riding configuration improved temperature uniformity without compromising structural integrity and incorporating side and bottom cage vents provided a further 5-7 °C reduction through improved airflow distribution. For the QSFP 1×1 model, a vapor-chamber heat sink outperformed a traditional zipper-fin design, reducing peak temperature by 5-6 °C under 44 W load conditions. This research demonstrates that optimized air-cooling architectures can effectively manage thermal loads in high-power-density connector systems without transitioning to liquid cooling. The validated CFD framework offers a robust tool for future design optimization, transient analysis, and system-level integration of connector-cooling technologies in data-center applications.
High-speed connectors, OSFP, QSFP, thermal management, air cooling, heat sink optimization, CFD, Ansys Icepak.
University of Illinois - Urbana-Champaign
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