高浓度丙酮VOCs高温预热近极限贫燃预混火焰特性的数值分析

为进一步对一种丙酮挥发性有机化合物（VOCs）焚烧炉进行设计优化和运行参数调节，本文对其在不同的燃料当量比、预热温度下的火焰特性进行了数值模拟，分析了其绝热火焰温度、着火延迟时间、火焰传播速度和一维火焰产物分布特性。研究结果表明：典型当量比（约0.113）下的绝热火焰温度为850~900℃，属于中低温燃烧，绝热火焰温度随预热温度和当量比（0.06~0.4）的升高均线性升高。预热温度和化学当量比对着火延迟时间的影响十分敏感。在其典型贫燃条件下，层流火焰传播速度随预热温度升高呈指数函数关系增大，随化学当量比增大而缓慢升高，且其层流火焰传播速度不超过150cm/s。反应过程首先发生丙酮的分解和部分氧化，并持续时间较长，仅当混合物的温度升高一定程度后才发生较剧烈的CO氧化。

Numerical analysis of flame characteristics of preheated acetone VOCs mixture under extremely fuel-lean conditions

The flame characteristics of an acetone VOCs incinerator at different fuel equivalence ratios and preheating temperatures are simulated to optimize its design and operation parameters. The factors of adiabatic flame temperature, ignition delay time, flame propagation velocity and one-dimensional flame product distribution are analyzed. The results show that the adiabatic flame temperature at the typical equivalence ratio (about 0.113) is 850—900℃, which belongs to medium-to-low temperature combustion. The influence of preheating temperature and chemical equivalence ratio on the ignition delay time is very significant. Under the typical fuel-lean condition, the laminar flame propagation speed increases exponentially with the increase of preheating temperature and slowly with the increase of chemical equivalence ratio, and the laminar flame propagation speed does not exceed 150cm/s. The decomposition and partial oxidation of acetone take place firstly, which can last for a long time. Only when the temperature of the mixture increases high enough, the more intense oxidation of CO takes place.