Investigation of flow boiling heat transfer characteristic of mixture refrigerant L-41B in a horizontal smooth tube

The saturated flow boiling heat transfer characteristics of L-41b, R1234ze(E)/R32 (27/73 mass%), inside an 8 mm ID horizontal tube were investigated. The experiment were carried out at the saturation temperature of 10 to 20°C with heat flux ranging from 5 to 10 kW/m2 and mass flux ranging from 200-500 kg/m2s. The influence of mass flux, heat flux, and quality on the heat transfer coefficients were examined and discussed. The experimental data of local heat transfer coefficients were compared with four well-known correlations available in literatures. Additionally, a new vapour-phase multiplier correlation to predict the local heat transfer coefficients of L-41b flow boiling inside smooth tubes was developed. The results show that the deviations of the new correlation are within –24.98% to +14.68% to the experimental data and that the 95% prediction values are within ±15%.