Flow boiling enhancement of R22 and a nonazeotropic mixture of R143a and R124 using perforated foils

Conference · Wed Jan 01 04:00:00 EST 1992

OSTI ID:5753710

Conklin, J C; Vineyard, E A

This paper reports an investigation of the flow-boiling heat transfer from the inside of a smooth tube and a novel surface designed to improve nucleate boiling heat transfer. This surface consists of a perforated brass foil inserted into the smooth tube. Two fluids were investigated: pure R22, and a nonazeotropic mixture of 75% R143a and 25% R124 (by mass). The experiment was conducted in an apparatus consisting of a variable speed compressor having a range of 500--3000 rpm and a counterflow concentric tube heat exchanger. The refrigerant circulates inside the central tube and water circulates in the annulus. For R22, the perforated foil insert increased the heat transfer coefficient of the smooth tube, particularly at lower qualities and heat fluxes, indicating augmentation of nucleate boiling. For this particular nonazeotropic refrigerant mixture, however, the perforated foil insert did not increase the heat transfer coefficient, which is most likely due to nucleate boiling suppression in NARMs at the qualities observed in the tests.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5753710
• Report Number(s): CONF-9206112-1; ON: DE92007692
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
AZEOTROPE
BOILING
DISPERSIONS
ENERGY TRANSFER
FLUIDS
FOILS
HEAT TRANSFER
MIXTURES
NUCLEATE BOILING
PERFORATION
PHASE TRANSFORMATIONS
PRESSURE DROP
REFRIGERANTS
TUBES
WORKING FLUIDS