旋流板对烟囱流场及除湿特性影响的数值研究

Numerical Simulation of Effect of Rotating-Steam-Tray on Chimney Flow Field and Dehumidification Characteristics

大型燃煤电站机组湿法脱硫后的烟气温度低、含湿量大,易与SO_2等气体形成酸液,对烟囱内壁造成严重腐蚀。在烟囱中加装旋流板装置进行烟气脱水,可以避免烟囱腐蚀。为分析旋流板对烟囱内部流动及除湿特性的影响,基于CFD方法,通过求解RANS方程、RNG k-ε湍流模型和DPM离散相模型对某电站锅炉烟囱加装旋流板装置前、后的流场特性及液滴运动特性进行了模拟和分析,在此基础上进一步比较了旋流板不同角度、高度、级数等参数对烟囱内部流场以及除湿效率的影响。结果表明:综合考虑压力损失和除湿效果两方面因素,叶片仰角为45°、安装高度为30 m的单级旋流板为最优选择。

With the application of wet flue gas desulphurization （WFGT） technology in large coal-fired power plant, the corrosion of chimney appears especially severe due to the acid liquor caused by the combination wet flue gas and SO2 gas. Rotating-Steam-Tray （RST） is an effective device to dehydrate and alleviate corrosion. In order to analyze the internal flow characteristics of flue gas in chimney with RST and its dehydration efficiency, the flow field of chimney and trajectories of droplets were simulated by solving the RANS equations combined with RNG k-c turbulence model and discrete phase model. In addition, the effects of the RST installed position, swirl angle and RSR stage number on the dehydrate efficiency are obtained. The optimum RST geometry parameters are given for the simulated chimney.