Operational Temperature Ranges in Pulsating Heat Pipes

The pulsating heat pipe (PHP), due to its ability to dissipate large amounts of heat and reduce temperature nonuniformity, is a promising technology for electronics cooling applications. In this work, the effect of the direction of change of heat dissipation rate in a PHP was explored. A quasi-steady state was approached by either increasing or reducing the evaporator heat input rate to a given level. It was found that instead of reaching a single steady-state evaporator temperature for a given heat input and condenser temperature, there is a range within which the evaporator temperature will fluctuate. Since most electronics cooling applications will have a non-steady heat removal requirement, understanding this phenomenon is of great importance for the design of PHP heat sinks.