花瓣喷嘴引射器引射系数的数值分析  

Numerical Simulation of Entrainment Ratio of Steam Ejector with Petaliform Nozzle

作　　者：张奕[1] 陈丹丹[1] 石嵩[1] 

机构地区：[1]南京师范大学能源与机械工程学院,江苏南京210042

出　　处：《南京师范大学学报（工程技术版）》2012年第1期29-32,共4页Journal of Nanjing Normal University(Engineering and Technology Edition)

摘　　要：花瓣喷嘴引射器可以为火炬气燃烧器提供燃烧所需要的空气,引射系数是这种引射器最重要的运行性能参数.使用可压缩流体模型,建立了引射器中蒸汽、空气及混合气体的运动方程、能量方程和组元方程.通过对这些方程的数值计算,分析了引射系数与蒸汽流量、喷嘴出口轴向位置(NXP)及混合室结构的关系.引射器运行时存在最佳蒸汽流量工况,在此流量下引射系数最大.管内蒸汽流量太大时,喷嘴出口产生激波,造成引射系数降低.喷嘴出口位于混合室内的引射系数比位于混合室外的大,出口离混合室越远,引射系数越小.混合室后接缩放管的引射系数比接直管时大50%.研究结果可对花瓣喷嘴引射器运行参数选择和结构设计提供依据.Steam ejector with petaliform nozzle can provide flare gas burner with air.Entrainment ratio is the most important operating parameter of the ejector.Compressible fluid conservation equations of momentum,energy and species are used to compute flow process in the ejector.It is found that the ejector achieves a maximum entrainment ratio when it operates at an optimal primary steam flow.Shock wave appears at exit of petaliform nozzle when steam flow is too large,which leads to the decrease of the entrainment ratio.When the nozzle exit position（NXP） is located in mixture room,the ejector gains a greater entrainment ratio than out of mixture room.The farther NXP from mixture room is,the less the entrainment ratio is.When a converging-diverging tube is connected to the mixture room,the entrainment ratio is as 1.5 times large as that connected to a straight tube.The results can be useful for the choice of the operating parameters and design of steam ejector with petaliform nozzle.

关 键 词：引射器 引射系数 花瓣喷嘴 数值计算 

分 类 号：TK413.2[动力工程及工程热物理—动力机械及工程]