Vadiml NIKOLAYEV, CEA

Liquid Film Modeling in the Pulsating Heat Pipes: from Nano to Macro-Scale

Vadim Nikolayev

Laboratory of Condensed Matter Physics (SPEC), CEA Paris-Saclay

The heat pipes are nowadays present in every electronic device. They provide thermal links connecting a hot area to be cooled (forming the evaporator) and a colder heat radiator area forming condenser. The Pulsating (called also Oscillating) Heat Pipe (PHP) is a closed capillary meandering between evaporator and condenser. It is filled by a pure fluid that forms inside a “train” of liquid plugs separated by vapor Taylor bubbles. Once the temperature gradient is applied, the train start oscillating spontaneously thanks to the fluid evaporation/condensation. This induces very efficient heat transfer. The PHP are cheap, light, and more efficient than other kinds of heat pipes. Their functioning is, however, quite difficult to predict theoretically, which hinders their industrial application. The reason is a complexity of physical phenomena that act on multiple length scales. The liquid films of Taylor bubbles are 10-100µm thick. The nanoscale is relevant to the moving contact lines that form because of the film drying in evaporator. The dynamics of the liquid plugs of 1mm diameter is inertia-controlled, creating a collective motion in a 10m long tube. In this presentation, I will address some of these phenomena concentrating of nano- and micro- scales and describe a framework that provides efficient prediction of the PHP functioning though the 1D numerical simulation.