折叠V形钝体火焰稳定器原型的稳燃机制研究

Flame Stability Mechanism of a Prototype Folded-V Bluff Body Flameholder

关键词:  加力燃烧室  火焰稳定器  折叠V形钝体  稳燃机制  槽向驻涡稳燃

Key words:  After burner  Flameholder  Folded-V bluff body  Flame stability mechanism  Widthwise stationary vortex enhancing flame stablity

摘要:

为了掌握折叠V形钝体这一新型火焰稳定器的稳燃机制，采用风洞实验与混合雷诺平均/大涡模拟结合的方法对常压条件下10组不同折叠角的折叠V形钝体火焰稳定器原型进行了冷态实验与热态数值模拟研究。其中冷态实验风速10～50m/s，热态数值模拟工况为进气温度700K、来流速度50～150m/s，当量比0.3～1。通过PIV实验测得了折叠V形钝体回流区冷态流动特征，并结合数值模拟方法研究并讨论了折叠V形钝体绕流尾迹区旋涡特征；通过数值模拟研究了燃烧条件下、折叠V形钝体下游槽向驻涡结构发展变化规律。研究初步探明折叠V形钝体总压恢复系数、阻力系数、抗吹熄能力与燃烧效率优于标准钝体的原因，并发现折叠角角度较小的折叠V形钝体，尾迹中心区域无典型回流区，但仍能通过槽向驻涡结构形成驻涡稳燃速度型，该速度型有利于冷态绕流流速的恢复与热态燃气的加速。

Abstract:

In order to obtain the flame stablity mechnism of a new proto type flameholder called Folded V bluff body， the cold experiments and combustion numerical simulation in atmospheric condition of 10 groups of folded V bluff body flameholders with different folding angles were carried out by wind tunnel and Hybrid RANS/LES method. The cold experimental wind speed is 10~50m/s， and the combustion numerical simulation conditions are： intake temperature 700K， inflow speed 50~150m/s， equivalent ratio 0.3 ~1. The characteristics of each groups’ wake flow were observed and measured by the PIV， and then disscussed with the help of numerical simulation. The development of widthwise stationary vortex in combustion phenomenon was further investigated by numerical method in detail. The mechanisms of the folded V bluff body’s advantages including total pressure recovery coefficient， resistance coefficient， blow out resistance and combustion efficiency compared with standard V type bluff body are verified. And it has been found that for the folded V bluff body with smaller folding angle， there is no typical recirculation zone in the center of the wake， but it can still form a stationary-vortex-steady-combustion velocity profile through the widthwise stationary vortex structure， which is conducive to the recovery of cold flow velocity and the acceleration of hot gas.