Boiling of R-134a in horizontal mini tube

this work presents the results of an experimental study carried out with r-134a to characterize heat transfer and pressure drop during flow boiling in a horizontal smooth tube of 2.6 mm id. the experimental tests included (i) heat fluxes in the range from 10 to 100 kw/m2, (ii) the refrigerant mass velocities set to discrete values in the range of 240-930 kg/m2s and (iii) saturation temperatures of 12 and 22°c. the study analyzed the heat transfer through the local heat transfer coefficient along the flow and pressure drop, under the variation of these different parameters. it was possible to observe the significant influence of heat flux on the heat transfer coefficient and mass velocity on the pressure drop, and the effects of saturation temperature. moreover, it was possible to produce a complete database.