基于贫油预混蒸发(LPP)的多点喷射低污染燃烧室头部方案研究

Study of a Dome for Low Emission Combustor with Multipoint Injection Based on LPP

对设计的基于贫油预混蒸发(LPP)的多点喷射低污染燃烧室头部方案,对其性能进行了数值研究。头部为中心分级燃烧,设计为同心圆式主、副模分区燃烧方式。主模燃油为多点喷射。应用CFX软件,从冷态流动、热态燃烧和污染物生成等三方面,对该燃烧室模型进行了研究。结果表明:冷态流动时慢车工况的回流区大于起飞工况,从设计上有效避免了回火与自燃的发生;慢车工况燃烧时因为直混燃烧,局部温度可达2 400 K以上;起飞工况燃烧时,主模燃油蒸发较好,但混合不是十分均匀,主、副模分区燃烧,主模火焰最高温度低于副模。对头部冷却和火焰筒中间1/3壁面应增大冷却效果。燃烧室燃烧效率非常接近100%。两个工况的污染物均集中于副模高温区,但总体生成量均很小。

Numerical simulation was done to discover the performance about a new type of combustor combined LPP and multi-point injection which may achieve ultra-low NOx emission.Staged combustion was achieved in the dome by co-axial main and pilot module with multipoint injection in main module.The investigation was conducted by ANSYS CFX from cold flow fields,combustion and emissions.Results show that the recirculation zone of idling condition is larger than that of taking off condition,and the problem of flashback or auto-ignition disappeared.Thetemperature at some points was above 2 400 K due to direct mixing combustion of idling condition.Good pre-vaporization and poor premixing were discovered in the main module,while the combustion of the main and pilot module was separate,with the higher temperature in pilot flame during taking off condition.Enhanced cooling technique should be applied to dome and middle 1/3 of liner.The combustion efficiency was as high as to nearly 100％.All emissions of both conditions are stacked in pilot flame,with the low quantity of total emission.