Condensation heat transfer of R1234ze(E)/R152a in horizontal tube and development of correlation

The flow condensation heat transfer performances of NCUR01, composed of R1234ze(E) and R152a by mass ratio 40:60, in horizontal smooth tubes with the inner diameter of 4 mm and 6 mm were investigated experimentally. Condensation heat transfer coefficients were measured in the region of mass flux from 100 to 200 kg m−2 s−1, heat flux from 5 to 10 kW m−2, saturation temperature from 303.15 K to 313.15 K and vapor quality from 0.1 to 1. The influence of mass flux, heat flux, saturation temperature, vapor quality and diameter on condensation heat transfer coefficients were analyzed. Experimental values of condensation heat transfer coefficient of smooth tube were also compared to the predicted values obtained by some well-known existing correlations. The mean absolute deviations of six selected correlations, for the condensation heat transfer coefficient of smooth tube, were estimated to be more than 30%. So, based on experimental data and some dimensionless parameters such as equivalent Reynolds number Reeq, condensation number Co and Bond number Bd, a new correlation was proposed to predict the condensation heat transfer coefficients of NCUR01. The mean absolute deviation of the new correlation is only 15.15% and absolute deviation within 30% occurs in 82% of data predicted by the proposed correlation.