Flow patterns

stability and heat transfer characteristices of two-phase flow in the internal thermosyphon boiling device with various helical channels have been visually observed by means of the transparent-film heating tubes. For the purpose of measuring the wall temperature more accurately

copper tuhes heated by resistance coils were used simultaneously. Experiments were carried out in seven models of internal thermosyphon tube with different geometrical dimensions five of them with helical Channel and the other two with straight flow annular channel. The working media were water

ethanol and aqueous solution of polyacrylamide. Experimental results were expressed with the relationships of q-Gt and q-hb

and the influences of channel geometries

media properties on the characteristics of fluid flow and heat transfer were discussed.