Convegni ATI - Accesso riservato soci CTI

Autore: G.A. Longo, A. Gasparella

Collana: CA - 62 - Fisciano 2007

Note:
This paper presents the experimental tests of HFC-410A condensation inside a brazed plate heat exchanger: the effects of refrigerant mass flux, saturation temperature and vapour super-heating are investigated.
At low refrigerant mass flux ( 20 kg/mqs) the heat transfer coefficients depend on mass flux and are well predicted by the Akers et al (1959) equation: forced convection condensation occurs. In the forced convection condensation region the heat transfer coefficients show a 30% increase for a doubling of the refrigerant mass flux. The condensation heat transfer coefficients of super-heat vapour are 8 – 10% higher than those of saturated vapour. The heat transfer coefficients show weak sensitivity to saturation temperature.
The frictional pressure drop shows a linear dependence on the kinetic energy per unit volume of the refrigerant flow and therefore a quadratic dependence on the refrigerant mass flux.