点火位置对中心分级燃烧室点火过程影响的研究

Effects of Ignition Position on Ignition Process of Internally-Staged Combustor

关键词:  燃烧室  点火  火焰传播  数值模拟  点火位置

Key words:  Combustor  Ignition  Flame propagation  Simulation  Ignition position

摘要:

燃烧室点火可靠性关系到发动机的整体性能，而点火位置对点火结果具有较大的影响。为此，对点火位置在回流区边缘中游的点火过程进行实验研究，对冷态流场和燃烧过程进行数值模拟并与实验结果对比，验证了数值模拟的准确性，研究了不同点火位置的火焰传播过程。结果表明，点火初始时刻，在流场的作用下，火核首先在燃油浓度较高的周向进行传播，同时在流场的作用下沿轴向向燃烧室下游传播，最终在回流区的作用下运动至燃烧室头部。当点火位置位于回流区中上游时，点火成功的关键是火焰传播到靠近头部燃油浓度较高的区域，而点火位置位于回流区下游时，其点火成功的关键是火焰传播到燃烧室中心位置并具有较高的能量。最佳点火位置位于回流区边缘的中游位置。

Abstract:

The ignition reliability of the combustor is related to the overall performance of aeroengine， and the ignition position plays an essential role in the ignition results. The flame propagation of the ignition position located at the midstream of recirculation zone edge has been investigated with experimental method. Then the numerical simulation method is used to investigate the cold flow and flame propagation， which is compared with the experimental results to verify the accuracy of the numerical simulation. Finally， the flame propagation at different ignition locations is studied by numerical simulation. The results indicate that the ignition kernel expands along the circumferential direction with higher fuel concentration and spreads along the axial direction under the function of flow field， and ultimately moves to the head of combustor under the action of recirculation zone. When the ignition location is located at upstream and midstream of the recirculation zone， the key of ignition success is that the flame propagates to the recirculation zone of high fuel concentration near the combustor head. For the ignition position located at the downstream of the recirculation zone， the key to ignition success is that the flame propagates to the central section of the combustor with higher heat release. The optimal ignition position is located at the midstream of the recirculation zone edge.