Microgrooved Heat Pipe

Abstract

Publisher Summary This chapter reviews the microgrooved heat pipe (MHP) research and development. A MHP is a reliable and efficient heat transport device for thermal control of integrated electronic circuits packaging, laser diodes, photovoltaic cells, infrared (IR) detectors, and space vehicles. The device transfers heat using evaporation and condensation of the coolant liquid, and the circulation of the coolant fluid is due to the capillary pressure generated due to the liquid meniscus difference at the evaporator and condenser sections. The length of the heat pipe is divided into three parts: evaporative, adiabatic (transport), and condenser sections. There are many factors to be considered while designing an MHP. For a working fluid, the compatibility, thermal stability, wettability, vapor pressure, high latent heat, high conductivity, low viscosity, high surface tension, and accepted freezing point have to be considered. The most important heat pipe design consideration is the amount of power that a heat pipe is capable of transferring. The chapter describes eight heat transport limitations of a heat pipe. These heat transport limits, which are a function of a heat pipe operating temperature, include viscous, sonic, capillary pumping, entrainment or flooding, boiling, condenser, vapor continuum, and frozen start-up. Furthermore, the chapter discusses issues such as the critical heat inputs, dryout length, fill charge, liquid temperature, and performance factor.