Characterizing Helium Pulsating Heat Pipes

A series of experiments and modeling activities have been carried out over the past few years at the University of Wisconsin - Madison with a helium pulsating heat pipe (PHP). This report describes the results of various methods used to characterize the behavior of the PHP, including developing correlations of the heat flux q" at the evaporator end in terms of dimensionless parameters such as the Karman number (Ka), Jacob number (Ja), and Prandtl number (Pr), and exploring the use of CFD tools such as ANSYS Fluent to visualize the internal 3D behavior of the two-phase flows. These combined efforts, along with other published reports, provide both physical understanding and design tools for future applications of helium pulsating heat pipes.