Experimental study on heat transfer characteristics of a condenser in the presence of air

In this study, the heat transfer characteristics of a condenser in the presence of air were investigated experimentally. A condenser system with a 450 mm × 447 mm × 630 mm chamber was designed and constructed. The condensing tube was copper coil tube each with a total length of 4650 mm, and the number of tube rows was 17. The experiments were conducted with different air mass fractions, inlet cooling water temperatures, cooling water flow velocities, and heat loads. With regard to the overall performance of the condenser, experimental results showed that the overall heat transfer coefficient decreased, whereas the condenser pressure and terminal temperature difference of the condenser both increased with an increase in the air mass fraction. With regard to the local heat transfer characteristics, the experimental results showed that the condensation heat transfer coefficients initially decreased slightly, then rapidly, and finally slightly again as the number of the tube row became higher in the flow direction of the steam when air leakage occurred in the condenser. The variation rate of the condensation heat transfer coefficient with the tube row significantly changed twice in the condenser. As the air mass fraction and the cooling water velocity increased, the critical rows, where the variation rate of the condensation heat transfer coefficient with the tube row significantly changed, generally moved upward. By contrast, the critical rows generally moved downward with increases in the inlet cooling water temperature and heat load.