Experimental Study On The Heat Transfer Performance In Direct Air-cooled Condenser Of Power Plant

In this paper, the snake-fin flat tube which is used in direct air-cooled condenser of power plant was used as the element of the experiment and parts of the wind tunnel experiment system was designed and put up. Heat transfer and flow characteristics for the vertical and inclined 30°arrangement of finned-tube, have been experimentally investigated. Convective heat transfer coefficient and flow resistance of the shake-plate-fin tube at different wind speeds were obtained. And the corresponding correlations and the curves of Nu with Re and factor f with Re were also obtained. The curves of Nu and factor f with Re for the two arrangement can be seen that with Reynolds number Re increases, Nu value increasing constantly, it is to say with the air speed increases, air side heat transfer ability of the finned tube was also increased; But with Reynolds number increases,f value continuously decreasing.At the same time, the flow flied at the outlet of inclined 30°arrangement of finned-tube was shot and its flow situation was got. By shooting picture results can be seen that smoke flowing into the finned space was cut by the fin, forms apparent parallel uniform flow, flows out of the finned space.The numerical simulation on the vertical and inclined 30°arrangement of finned-tube was carried on, respectively. Air-side flow flied situation was obtained in both cases. By simulation results can be seen after rectified by the fin, air forms parallel flow at finned tube outlet, and will remain relatively long distance, although at the rear of the tube, backflow was produced, but its area is lesser, and its speed is low, accordingly its influence on mainstream is not obvious.According to the experimental and simulated results of the single-row tube, numerical simulation on the space of the adjacent A unit was carried on and the distribution of the hot air flow was obtained. By simulation results can see:in adjacent A unit, air flow in symmetric state into the air space, and no eddy current generated.