Experimental study on flow boiling heat transfer of HFE-7100 in minichannel heat sinks for professional-grade server chips cooling

Micro/mini-channel heat sinks play a crucial role in the heat dissipation of electronic components, such as server chips. In this study, the minichannel heat sinks were designed by 6061‑aluminum alloy to investigate their heat dissipation capabilities. Flow boiling experiments with low flow velocities in minichannels were conducted in the smooth parallel minichannel (SPMC) and porous parallel minichannel (PPMC) heat sinks at conditions of high power and low heat flux. The mass fluxes varied from 121.0 to 241.9 kg/(m²s), and the effective heat fluxes varied from 0 to 9.1 W/cm². The effects of mass flux, heat flux, inlet temperature, and surface structure on heat transfer and flow pattern transition during flow boiling of HFE-7100 were discussed. The research indicates that at the room-temperature condition, the maximum decrease in wall temperature is 2.39 % between them under a mass flux is 181.4 kg/(m²s) and a heat flux is about 7 W/cm². The wall temperature can be maintained below 75 °C, while the pressure drop is consistently below 0.6 kPa at all conditions. With the increase in effective heat fluxes, the boundary of flow pattern transition becomes less distinct, slug flow and churn flow are the main flow patterns in the mid/downstream of minichannels.