Foam flow of oil-refrigerant R12 mixture in a small diameter tube

Flow Condensation of Pure and Oil Contaminated Refrigerant HFC134a in a Horizontal Tube

Investigation of Using Nonazeotropic Refrigerant Mixture as the Replacement for R12

This paper investigates the effects of nonazeotropic refrigerant mixtures (NARMs) as replacement of CFCs. The thermodynamic propert1es of NARM R22/R142b which is harmless to ozone layer are analyzed. The tests about water-to-water heat pump and dual-evaporator refrigerator-freezer using R22/R142b as alternative to R12 are introduced. The test results show R22/Rl42b is of energy conserving effec...

Two Phase Heat Transfer Characteristics in a Vertical Small Diameter Tube at Sub Atmospheric Pressure

Two-phase heat transfer is experimentally examined through vertical small diameter tubes, D =1.45 and 2.8 mm using water under a pressure of 50 to 81 kPa and a natural circulation condition. The pool boiling correlation by Stephan-Abdelsalam and the thermosyphon boiling correlation by Imura, et al. predict the measured experimental data in the 2.8 mm tube with an error of -30%. A large heat tra...

Flow visualization and pressure drop for refrigerant phase change and air-water flow in small hydraulic diameter geometries

A comprehensive study of two-phase flow mechanisms and pressure drop in horizontal small hydraulic diameter tubes was conducted. Co-current flow of air-water mixtures in four round tubes and one rectangular tube with hydraulic diameters ranging from 5.5 mm to 1.3 mm were investigated. Bubble, dispersed, elongated bubble, slug, stratified, wavy, annular-wavy, and annular flow patterns were obser...

Capillary flow of oil in a single foam microchannel.

When using appropriate surfactants, oil and aqueous foam can be intimately mixed without the foam being destroyed. In this Letter, we show that a foam, initially free of oil, can draw an oil drop under the action of capillary forces and stretch it through the aqueous network. We focus on the suction of oil by a single horizontal foam channel, known as a Plateau border. In such confined channels...