Oblique-fin heat sink design for uniform CPU cooling in immersion-cooled servers

초록

This study investigates single-phase immersion cooling (SPIC) as an advanced thermal management strategy for multi-CPU server platforms, focusing on the Intel (R) Server Board S2600BPB equipped with oblique-fin heat sinks arranged in novel configurations. Using FC-40 as the coolant, the research explores the combined influence of heat sink design and coolant flow rates on CPU temperature, temperature uniformity index (TUI), and pumping power across a broad range of CPU thermal design powers (TDPs). The proposed oblique-fin designs, featuring converging channel formations, demonstrate notable improvements in temperature uniformity and cooling efficiency, with the most significant enhancement observed at lower flow rates. Under a 500 W TDP, the design achieves CPU temperature reductions of up to 7 degrees C and TUI improvements of up to 20 %. This configuration achieves a favorable trade-off between thermal performance and hydraulic efficiency, incurring less than a 3 % increase in pumping power despite enhanced heat removal capabilities. Moreover, the design effectively dissipates heat from CPUs and key downstream elements, including the Platform Controller Hub (PCH) and Voltage Regulator (VR), alleviating thermal cascade effects typical in server systems. Increasing the coolant flow rate from 2 to 7 L/min at 500 W TDP results in temperature reductions of approximately 8.7 degrees C for DIMMs, and more substantial decreases of 18.5 degrees C and 16.4 degrees C for the PCH and VR, respectively. This work establishes oblique-fin heat sinks as a promising solution for uniform, efficient thermal management in immersion-cooled servers.

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