| In recent years,direct air-cooled technology has been rapid development. It is the key to the effective operation of the direct air-cooled power plants that the direct air-cooled condenser‘s reliable heat transfer performance. The DACC’s heat transfer performance seriously affected by environmental wind.In this paper, Based on the operating characteristics of direct air-cooled unit, we propose a device used in the air-cooled platform, that is called the expansion pressure deflector. The expansion pressure deflector has two kinds of type. One is diffuser type, the other is diffuser diversion type. We hope it could reduce the impact of environmental wind on the DACC that by improving the DACC’s flow field. According to the factors that affect the diffuser tube, presented 11 different sets of structural parameters for the expansion pressure deflector. Reference to a domestic power plant’s 600 MW Direct Air-Cooled Unit, Based on the Computational Fluid Mechanics(CFD), calculating the heat transfer performance of air-cooled condenser that installed 11 groups of expansion pressure deflector.The results show that, the expansion pressure deflector could eliminate the vortex effectively that in the flow field of DACC, but also could reduce the average temperature of the fan inlet, Among them, the improve effect of the windward side DACC is particularly evident. The expansion pressure deflector could improve the overall DACC’s heat transfer performance, especially the windy conditions. The diffuser type device is better than the straight hole and the diffuser diversion type device, under the same conditions. Comparative results, The fifth is the best in the 11 sets of parameters for the expansion pressure deflector. We suggest that choose the expansion pressure deflector that have the diffuser type and high open rate. Thickness of the device is recommended 0.2 m, diffuser ratio is recommended 1.4, the angle diffuser is recommended about 14° or greater than 14°. |
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