Abstract

Results of heat transfer and pressure drop investigation during flow boiling of R22 and R134a inside smooth tubes and selected enhanced tubes are presented. Corrugated and microfnned tubes served as enhanced tubes. The experiments have been conducted for average saturation temperature 0°C. Inlet vapour quality was set to 0 and outlet quality: 0.7. Mass flux density varied from about 250 to 500 kg/(m²s). The experimental results have been compared with heat transfer coefficients calculated from selected correlations. The test stand and experimental procedure are described. Higher average evaporation heat transfer coefficierrts and plessure drops for enhanced tubes have been observed. Refrigerant R22 has an evident superiority over R134a for each tested type of tube.