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

摘要

Flow boiling heat transfer coefficients of R22, R134a, R507, R404A and R410A inside a smooth horizontal tube (6 mm ID, 6 m length) were measured at a refrigerant mass flux of about 360 kg/m2 s varying the evaporating pressure within the range 3-12 bar, with heat fluxes within the range 11-21 kW/m2 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%).