Numerical study on supersonic combustion of kerosene-air premixed flow

对以高温燃气作为引导火焰的煤油．空气预混气流超声速燃烧进行了数值模拟，系统研究了预混气流的温度、压力、当量比，以及预混气流与高温燃气的压力匹配关系等多种重要因素对超声速燃烧的影响。结果表明：随着预混气流静温、静压的升高，着火点诱导的压缩波增强，最高燃烧温度升高，火焰传播角相应增大；预混气流的当量比为化学恰当比时，燃烧温度最高；与静压匹配的情况相比，静压不匹配情况下的火焰传播角增大，当预混气流的静压高于高温燃气的静压时，着火点前移，反之，着火点则后移；此外，在多种情况下，燃烧室下壁面边界层都出现了自燃现象

煤油-空气预混气流超声速燃烧数值研究

对以高温燃气作为引导火焰的煤油-空气预混气流超声速燃烧进行了数值模拟，系统研究了预混气流的温度、压力、当量比，以及预混气流与高温燃气的压力匹配关系等多种重要因素对超声速燃烧的影响。结果表明：随着预混气流静温、静压的升高，着火点诱导的压缩波增强，最高燃烧温度升高，火焰传播角相应增大；预混气流的当量比为化学恰当比时，燃烧温度最高；与静压匹配的情况相比，静压不匹配情况下的火焰传播角增大，当预混气流的静压高于高温燃气的静压时，着火点前移，反之，着火点则后移；此外，在多种情况下，燃烧室下壁面边界层都出现了自燃现象

大速差同向射流——一种新型火焰稳定与强化燃烧的空气动力学原理

本文介绍了一种稳定火焰和强化燃烧的新型空气动力学原理——大速差同向射流技术。单股或多股高速小射流(空气、蒸汽或其它气体)与低速的主气流(燃料和空气混合物)同方向射入燃烧室,可以产生高湍流强度的大回流区,从而可以使可燃混合物与高温回流烟气有效地混合,以维持燃烧室内稳定而强化地燃烧,甚至对于着火性能很差的燃料也是如此。这是继传统的旋流燃烧器和钝体燃烧器之后又一种新型的有效而实用的火焰稳定方法。基于这种原理研制的煤粉燃烧器更具有优良的性能,并且在结构上也很简单。这种类型的煤粉预燃室,已经在电站和工业锅炉上安装使用。目前,使用这种预燃室可以在冷风条件下成功地启动贫煤(V~f30％)锅炉及低负荷情况下仍能维持燃烧。这项新技术所展示的火焰稳定和强化燃烧原理在燃烧界引起了广泛的关注和兴趣

Coflow jets with large velocity difference - a new aerodynamic principle of flame stabilization and combustion intensification

A new aerodynamic principle of flame stabilization and combustion intensification, the coflow jets with large velocity difference, is described. One or more small high-velocity jets of air or steam, injected off the axis and in the same direction as the low-velocity main fuel-air flow into the combustor, create a large recirculation zone of high turbulence intensity in which the combustibles and high temperature gases are effectively mixed, so that stable and intensive combustion can be maintained even for fuels with poor ignition. A pulverized coal combustor based on the principle mentioned above is shown to be characteristic of excellent combustoom and a simple structure. A number of precombustors of this type are in operation at some power stations and industrial boilers of China. Using such precombustor, successtul startups and part-load operation of the boilers have become available under conditions of unpreheated air and low-grade coal with volatiles as low as 15% and ash content as high as 30%. This principle shows good promise as an attractive new technology of combustion