BOILING OF FREON-114 IN A THREE-FOOT STRAIGHT TUBE EVAPORATOR

摘要

Experimental determinations of heat flux were made with Freon-ll4 flowing by natural circulation through a steam-heated vertical tube with and with¬out swirl promoters. The heated length of the 7/8-inch outside diameter copper tube was 35 inches, the saturation temperature of Freon-ll4 at test-section flow exit l60°F., and the heat flux range from 7^000 to 70,000 Btu./hr./sq.ft. Heat flux measurements at specified conditions were compared to determine the degree of fouling and the effect of swirling flow on heat transfer efficiency.nExperimental data showed that the circulation of water-saturated Freon-ll4 at 200°F. for 2-1/2 hours did not produce sufficient steel corrosion prod¬ucts to foul the surface of the evaporator. Swirl promoters were effective in reducing dry-wall vapor binding at the higher heat loads. The 50 per cent increase in maximum heat flux observed was limited by the low liquid-to-vapor ratio of the bulk Freon leaving the evaporator. An increase in input flow to the evaporator by forced circulation or increased liquid head should produce an additional increase in maximum heat flux.