Experimental Investigation and Comparison of Heat Transfer coefficient of a Two Phase Closed Thermosyphon

In this study, we investigated and reviewed the heat transfer equations of the evaporator and condenser of a two phase closed Thermosyphon as well as the differences between this equations for a working fluid and different conditions. The heat transfer limits of a two phase closed thermosyphon such as sonic, flooding (or entrainment) dry-out and boiling are investigated . A good agreement is observed between analytical results of this study and the analytical and experimental results of those available in the open literature. The heat transfer limits are very important in thermosyphons and have to be calculated accurately while the input heat must be lower than the heat transfer limits for the operations of thermosyphon without any problem. Also by using the experimental results a semi empirical equation for heat transfer coefficient of evaporator was proposed.

thermosyphon; heat transfer limit; flooding limit; boiling limit; dry-out limit