Abstract
To develop a comprehensive performance evaluation model of heat transfer tube, the flow condensation heat transfer experiment of R1234yf inside the tube was operated. In this article, the effect of mass flux, condensation temperature, and fin structural parameters on the heat transfer characteristics was studied, and then corrections of heat transfer coefficient and pressure drop predictive effect were checked. Results show that the heat transfer coefficient and pressure drop increase with increasing mass flux and condensation temperature, and the heat transfer enhanced ratio is 2.53∼3.67 while the pressure drop deterioration ratio was 1.95∼2.49 for the micro-fin tube; the Yu and Koyama correlation has a best predictive effect for the heat transfer coefficient with the average and mean deviation of 0.77% and 10.84%, and the Han et al. correction shows the best predictive effect for the pressure drop with the average and mean deviation of 1.82% and 6.23%. Finally, the heat transfer coefficient per unit pressure drop was selected as evaluation index of heat exchanger comprehensive performance, a model was developed based on the Yu and Koyama correlation, and it can predict the heat transfer coefficient per unit pressure drop with a mean absolute prediction error of −1.65%.
Highlights
For the last few years, high efficiency compact heat exchangers are gaining widely popular within industrial sectors, due to it does not create much additional resistance with increasing the heat transfer coefficient
The condensation heat transfer coefficient of R1234yf inside the smooth tube under different condensation temperatures and mass fluxes is shown in Figure 7(a); the heat transfer coefficient increases with increasing mass flux and reducing condensation temperature
The influencing mechanism of mass flux is the vapor and liquid velocities all become bigger with the increment of mass flux, and the velocity difference between vapor and liquid becomes bigger due to the difference between vapor and liquid densities; they all can enhance fluid turbulence and enhance heat transfer effect
Summary
For the last few years, high efficiency compact heat exchangers are gaining widely popular within industrial sectors, due to it does not create much additional resistance with increasing the heat transfer coefficient. The influence of mass flux, saturation temperature, and vapor quality at the inlet and outlet of test section on the heat transfer characteristics inside the tube is mainly studied.
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