塔内排烟对空冷塔热力性能的影响

为研究塔内排烟对空冷塔热力性能的影响机理,以2×600MW机组空冷塔为对象,结合实测数据建立了恰当的数学模型。采用了数值模拟方法,计算了不同环境温度条件下,空冷塔内有、无排烟装置时散热量的变化情况,并根据流场图分析了塔内烟气的流动状态及其对空冷塔热力性能的影响方式。结果表明,随着外界环境温度的变化,无论塔内有、无排烟装置时,空冷塔散热量都随环境温度呈现出近似线性的变化趋势。塔内排烟有利于空冷塔的散热,但促进作用有限,且随着外界环境温度升高而逐渐减小。塔内热流体沿逆压梯度方向流动,烟气与热空气流动分层较为明显,二者在塔出口位置扩散并融合为一整体。研究结果对空冷塔的设计和应用有一定的参考意义。

Influence of Flue Gas inside Tower on the Thermal Performance of Air-cooled Towers

In order to study the influence mechanisms of flue gas inside tower on the thermal performance of air-cooled towers , air-cooled towers of 2×600MW units were chosen as research object, and the appropriate mathematical model was established based on the measured data. Through the methods of numerical simulation, the changes of heat dissipation of air-cooled towers with or without smoke exhaust devices inside were calculated under different ambient temperature conditions . Meanwhile , flow status of the flue gas inside towers and its influence ways on the thermal performance of air-cooled towers were analyzed according to the flow field diagram. Results showed that, with the varies of the ambient temperature , there was an approximate linear trend between the heat dissipation of air-cooled towers and ambient temperature , no matter whether the tower is equipped with smoke exhaust devices. What's more, flue gas inside tower was beneficial to the heat dissipation of air-cooled towers, but the promotion function was limited and gradually decreased with the increase of ambient temperature. The thermal fluid inside tower flowed against the direction of pressure gradient. There was obvious stratification between flue gas and heated air, which of the two were diffused and integrated into a whole one. The results would be of some reference significance for design and application of air-cooled towers.