ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
ENHANCEMENT OF BOILING AND EVAPORATION ON STRUCTURED SURFACES WITH GRAVITY DRIVEN FILM FLOW OF R-11
Аннотация
On the heated vertical plates having the surface structures of fine size, falling film of R-11 was evaporated at atmospheric pressure. The tested surfaces are the mechanically prepared porous (PP), vertically grooved (VG), and laterally grooved (HG) surfaces. The porous surface showed the highest heat transfer performance, demonstrating the advantage of enhanced nucleation of bubbles in the film flow. Its heat transfer coefficient is higher than that of pool boiling, and remains high until the complete dry-out of liquid.
On VG, the predominant mode of heat transfer is evaporation from the film surface. Its heat transfer coefficient is maximized at an optimum liquid flow rate, however, lower than that of PP.
The enhancement on HG was found to be moderate.
On VG, the predominant mode of heat transfer is evaporation from the film surface. Its heat transfer coefficient is maximized at an optimum liquid flow rate, however, lower than that of PP.
The enhancement on HG was found to be moderate.