Subject: Numerical simulation of the oscillating menisci in a capillary
Location: SPEC/SPHYNX, CEA-Saclay (Center of the Commission of Atomic Energy of France in a Paris suburb)
Duration: 1 year
Date of start: October 2015
Criteria of the candidate selection: We are looking for a person with the background in the physics of fluids and a solid experience of C++ programming. Knowledge of the Visual Studio and Windows programming is a plus.
This work falls within the scope of the research program on pulsating or oscillating heat pipes (PHP) led at CEA. A heat pipe is a device for transferring the heat from hot to cold spots situated at a certain distance. It is a sealed tube containing liquid and gas phases of a pure fluid. The liquid is vaporized at the hot portion of the tube (evaporator) and the energy is stored as the latent heat of the liquid-vapor phase change. The vapor is then transported to the cold part (condenser) and released there during the inverse phase change. The pulsating heat pipe (PHP) is a simple capillary tube without any internal structure bent so that it meanders between condenser and evaporator. It is filled partially by the liquid and a sequence of bubbles and liquid plugs forms inside it.
Spontaneous oscillations of the bubbles and plugs appear in such a system when the difference of temperatures of evaporator and condenser exceeds a threshold. Due to the convective heat transport capability, the PHP appears to be in many respects more efficient in comparison with the other types of the heat pipes. Because of its complexity, it is difficult to understand and to model (see above web link). The most common flow type in the PHP is the slug flow involving so called "Taylor bubbles". Thin fluid films "Landau-Levich" films are formed on the tube walls during the bubble motion. The physics of their evaporation/condensation during the oscillating bubble motion will be studied theoretically and numerically by the posdoc. This work will be performed in interaction with the experimental part of the team where the corresponding experiments are under way. This research is carried out in the framework of the ANR project AARDECO in collaboration with two more academic laboratories Pprime/Poitiers and CETHIL/Lyon) and the R&D divisions of PSA Peugeot-Citroën and Liebherr Aerospace Toulouse.