| With the increasing attention of people pay to environmental protection and the growing scarcity of water resources, traditional water-cooled thermal power is facing serious challenges, because it consumes more water and has negative influence on the environment. Therefore, in recent years, air-cooling system has been widely used in the poor water and plentiful coals in North China. SCAL indirect air-cooling system combines the advantages of Heller and Harmon air-cooling system, the radiators are arranged vertically around the tower, and use the surface condenser. Its cooling performance is affected by some factors, including the structure, environmental condition, circulating water parameters, and the crosswinds causes people’s attention increasingly. Based on the actual operation, the cooling performance is influenced greatly by the crosswinds, especially when the ambient temperature is high, the condenser’s back pressure rises because the circulating water cannot be sufficiently cooled, so the economical efficiency would reduce, or the load would be limited.The paper establishes a more sophisticated three-dimensional numerical model of the tower by means of CFD to study the flow patterns and heat transfer performance under the crosswinds. The results show that heat dissipating capacity and ventilation reduce with the increase of wind speed, and their changing tendency are similar. With the wind speed increasing, the flow around cylinder play a leading role, it would led the inside and outside differential pressure of the side radiator and the ventilation reduce; the heat dissipating capacity of windward radiator will increase, but it is not enough to make up for the losses in other radiator; leeward side radiator is affected by the air flow and air swirl.In order to clarify the study direction of anti-wind measures, the quantitative analysis for the influence of the crosswind effect at top and bottom of the tower was carried on, results show that flow around the radiator is the main reason to lead ventilation reduce, so the exploration of anti-wind measures should be focused on the bottom of the tower. This paper analyzes three kinds of anti-wind measures, results show the measure of adjusting louver can not achieve the desired effect. In comparison, the measure of wing wall can ease the impact caused by crosswinds, results show that the wing wall which is arranged perpendicular to the incoming flow with the width of 23.6m and the porosity of 0.6 is the most feasible solutions. Considering the limited space, this paper presents the sub-sector water distribution scheme, according to the proportion of heat dissipating capacity of different sectors to distribute the circulating water, which can ease the influence of crosswinds without installing any device.The heat dissipating capacity is the main parameter of the cooling performance, but it is not enough to know the economic indicators. In order to evaluate the economic benefit of anti-wind measures intuitively, this paper establish the off-design mathematic model according to the conventional thermal balance methods, combining with the results of numerical simulation, the economic indicators were analyzed, the results show that when the wind speed is high enough (v≥12m/s), sub-sector water distribution scheme can obtain good economic benefit. The wing wall can obtain good economic benefit in common wind speed (v=8m/s), comparing with the situation of lacking any anti-wind measures, in the condition of THA, the back pressure reduces 1.54 kPa, the standard coal consumption rate for generating reduces 2.06 g/kW-h, and the generated energy raises 4.57MW. |
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