A Study of High Temperature Heat Pipes and the Impact of Magnetic Field on the Flow of Liquid Metal

A study of high temperature heat pipe was conducted to understand its characteristics. A review of working fluid, temperature, wick structure, problems, operational limit and applications was done. Alkali metal were concluded as the most viable candidate for the working fluid. The impact of three parameters namely magnetic field, heat flux and temperature was analyzed on the performance of HTHP (High Temperature Heat Pipe). The presence of magnetic field had the most considerable impact on reducing the pumping limit of the heat pipe while the temperature had almost negligible effect. Magnetic field results in the pressure drop and adversely affect the fluid inside the heat pipe. The adverse impact was characterized due to the conducting nature of the working fluid. Analyzing the Magnetohydrodynamic (MHD) equation showed that the reason for the pressure drop inside heat pipe was Lorentz force. The flow was found to be dependent on three dimensionless number namely Capillary number, Hartmann number and aspect ratio of heat pipe. Thereafter a mathematical model was developed to inquire if the presence of non-uniform magnetic field can increase the capillary limit over the uniform magnetic field. It was found that an exponential varying field along the axial direction of the heat pipe improves the performance of the device. The results corresponding to uniform and non-uniform field were compared and concluded in our study