COMPLETE TRANSIENT 2-DIMENSIONAL ANALYSIS OF 2-PHASE CLOSED THERMOSIPHONS INCLUDING THE FALLING CONDENSATE FILM

A transient two-dimensional thermosyphon model is presented that accou nts for conjugate heat transfer through the wall and the falling conde nsate film. The complete transient two-dimensional conservation equati ons are solved for the vapor flow and pipe wall, and the liquid film i s modeled using a quasi-steady Nusselt-type solution. The model is ver ified by comparison with existing experimental data for a low-temperat ure thermosyphon with good agreement. A typical high-temperature therm osyphon was then simulated to examine the effects of vapor compressibi lity and conjugate heat transfer.