Numerical simulation and experimental study of the flow heat transfer characteristics of rectangular micro-grooved ultra-thin flat plate heat pipes

Ultra-thin flat heat pipes (UTFPs) effectively address the heat dissipation challenges of contemporary compact electronic devices, owing to their superior thermal conductivity and high stability in confined places. This paper established the VOF vapor-liquid two-phase flow model of the rectangular micro-grooved ultra-thin flat heat pipe (M-UTFP) and constructed a test platform for evaluating the heat transfer performance of heat pipes, incorporating various filling rates (30%, 35%, 40%, 45%) and heat fluxes (0.375 × 10 6 W/m 2 , 0.5 × 10 6 W/m 2 , 1 × 10 6 W/m 2 , 1.25 × 10 6 W/m 2 , 1.67 × 10 6 W/m 2 ). The findings indicated that the phase transition initially transpires on the heating surface of the evaporation section, while the vapor on the wall of the condensing section generates a liquid film after condensation. The optimal liquid filling rate for the M-UTFP was 35%. A heat flux of 1 × 10 6 W/m 2 maintained a stable temperature fluctuation in the evaporation section of the heat pipe, thereby enhancing heat transfer efficiency. These findings align with simulation results, offering data references and design principles for the development of ultra-thin electronic cooling systems, such as those used in chips, and extending the application scope of UTFPs.