当量比和初始混合模式对无焰燃烧的影响  

Effects of Equivalence Ratio and Premixing Pattern on Flameless Combustion

作　　者：李鹏飞[1] 王飞飞[1] 米建春[1] 梅振锋[1] 

机构地区：[1]北京大学,湍流与复杂系统国家重点实验室,能源与资源工程系,北京100871

出　　处：《工程热物理学报》2011年第9期1592-1596,共5页Journal of Engineering Thermophysics

基　　金：国家自然科学基金项目(No.10772006);煤燃烧国家重点实验室开放基金资助项目(No.FSKLCC0801)

摘　　要：对燃料-空气非预混、完全预混与部分预混三种混合模式下的无焰燃烧状态进行了实验和数值模拟研究。采用了详细化学反应机理和已被实验验证的算法进行数值模拟。研究发现三种混合模式下无焰燃烧状态的区别是由初始反应物的射流总动量的不同决定的。当炉内大尺度流场结构类似时,初始反应物射流总动量越大,炉内烟气循环越剧烈,温度分布越均匀,峰值温度越低,NO_x越低。数值模拟发现OH自由基峰值位置与温度峰值位置基本重合;而H_2CO峰值位置主要分布在主反应区中的低温区域。实验测量了当量比对无焰燃烧炉内温度和NO_x排放值的影响,并发现部分实验还发现,部分预混、非预混和完全预混无焰燃烧时,NO占NO_x总量的百分比分别为94.3%、91.9%和76.9%。This paper experimentally and numerically investigates the fuel-air premixing patterns （non-premixed, fully premixed and partially premixed） on flameless combustion. The detailed reaction mechanism and the verified algorithm are used in the numerical simulation. It is found that the performance of flameless combustion depends more on the initial reactant jet momentum than on the premixed pattern. Also, the internal fue-gas recirculation is accelerated by increasing the initial reactant jet momentum; as a result, the temperature distribution is more uniform, the peak temperature and NOx emission decrease. Numerical simulations show that the peak concentration of OH radical coincides approximately with the peak temperature. Moreover, the peak H2CO radical is distributed in the low temperature zone of the main reaction region. The influences of equivalence ratio on flameless combustion and NOx emissions are examined by experiments. The percentage of NO in total NOx is found experimentally to be 94.3%, 91.9% and 76.9%, respectively, for the partially premixed, non-premixed and fully premixed combustion.

关 键 词：无焰燃烧 高温空气燃烧 预混 NOx 当量比 

分 类 号：O362[理学—流体力学]