Flow-boiling of R22, R134a, R507, R404A and R410A inside a smooth horizontal tube

Flow boiling heat transfer coefficients of R22, R134a, R507, R404A and R410A inside a smooth horizontal tube (6 rum I.D., 6 in length) were measured at a refrigerant mass flux of about 360 kg/m(2) s varying the evaporating pressure within the range 3-12 bar, with heat fluxes within the range 11-21 kW/m(2). The experimental data are discussed in terms of the heat transfer coefficients as a function of the vapour quality. The experimental results clearly show that the heat transfer coefficients of R134a are always higher than those pertaining to R22 (from a minimum of + 6 to a maximum of + 45%). (C) 2005 Elsevier Ltd and IIR. All rights reserved.