湿烟羽形成机理与消散技术数值分析

Numerical Analysis of Wet Plume Formation Mechanism and Dissipation Technique

湿烟气由烟囱出口进入温度较低的环境空气会形成湿烟羽现象,产生视觉污染。分析了湿烟羽的形成机理和消散技术,采用数值计算研究了不同湿烟羽消散技术的特点。结果表明,烟气直接加热、烟气直接降温和烟气降温再热可以消散湿烟羽;烟气降温再热消散湿烟羽使用范围最大,烟气直接加热次之,烟气直接降温最小;环境温度低于10℃,环境相对湿度大于40%时,烟气直接加热和烟气直接降温消散湿烟羽的升温幅度和降温幅度较大,湿烟羽消散难度大;环境温度低于5℃时,只能采用烟气降温再热消散湿烟羽。

Wet plume forms when the wet flue gas from the chimney exits into the ambient air,which would lead to visual pollution.The mechanism of wet plume formation and dissipation is analyzed.Characteristics of different wet plume elimination techniques are studied with numerical calculation.The results show that,direct heating of flue gas,direct cooling of flue gas and cooling and reheating of flue gas can eliminate wet plume.Application scope of cooling and reheating of flue gas is the largest,and direct cooling of flue gas is the smallest.When the ambient temperature is lower than 10 ℃ and the relative humidity is larger than 40%,heating and cooling extent applying direct heating of flue gas and direct cooling of flue gas is too large to eliminate wet plume;when the ambient temperature is lower than 5 ℃,only cooling and reheating of flue gas can eliminate wet plume.