A study on thermal and hydraulic performance of ultra-thin heat pipe with hybrid mesh-groove wick

Abstract

High power electronics require ultra-thin heat pipe (UTHP) with more efficient heat transfer capabilities to meet thermal management challenges. And the design of the wick structure is crucial to the heat transfer performance improvement of the UTHP. At the present work, a thermo-hydraulic model is proposed for UTHP with composite mesh-grooved wick structure and the potential applications of the hybrid wick with non-full coverage by mesh is analyzed. According to the different mesh coverage areas, the wick structures are classified into three types, including evaporator covered, evaporator-adiabatic section covered, and full covered. The results show the flow characteristics and thermal performance of UTHPs is closely related to mesh coverage area and vapor core thickness. The reduction in mesh coverage area causes an expansion in vapor space, the vapor velocity and the vapor pressure drop both decreases, the mass flow rises with the higher vapor-liquid circulation efficiency. The liquid pressure drop is positively related to working fluid mass flow. Moreover, a theoretical model to predict the heat transfer limit of the heat pipe with composite wick was established and verified by experimental results with a maximum error of 3.63%.