Experimental study on thermal performance of ultra-thin flat heat pipe with double condensation sections for server memory modules

This paper focuses on the thermal management of server memory modules. A series of UFHPs (ultra-thin flat heat pipes) using SF33 as the working fluid, with varying filling amounts, bending angles, and internal groove structures, were fabricated. The experiment investigated the heat transfer performance of UFHPs by analyzing the optimal filling amounts corresponding to different bending angles and the impact of internal groove structures on heat transfer. The experimental results indicate that a low filling amount stabilizes more quickly under the same heating power but requires higher heating power for full start-up. Bending the heat pipes enhances heat transfer performance, with an optimal filling amount existing for different power levels and bending angles. Among the three heat pipe configurations, the NCP type groove exhibits the best capillary-driven liquid flow characteristics, while the RCP type heat pipe demonstrates the best heat transfer performance. Compared to current memory module cooling methods, the RCP-60 type UFHP with dual condensation sections offers superior thermal performance. Under conditions of a 40 °C cooling water temperature and a 16 W heating power, it maintains the memory module temperature at approximately 48 °C. Furthermore, this UFHP exhibits a remarkably low thermal resistance of only 0.33 K/W and an exceptionally high effective thermal conductivity of 15,000 W/(m⋅K). This provides an effective design approach to ensure excellent thermal management for server memory modules and other low-power electronic devices.