中心分级燃烧室头部冷态流场特性实验研究

Experimental Study on Characteristics of Cold Flowfield in a Centrally-Staged Combustor Dome

关键词:  燃烧室  旋流数  粒子图像测速仪  流场  耦合作用  回流区

Key words:  Combustor  Swirl number  Particle image velocimetry  Flow field  Coupling effect  Recirculation zone

摘要:

为了深入研究中心分级燃烧室的流场特性，采用PIV方法对其头部冷态流场开展了实验研究，重点分析了中心分级燃烧室头部流场的结构特征以及主燃级旋流数对头部流场的影响。实验结果表明：中心分级燃烧室头部典型流场结构形成一个较大的中心主回流区、较小的端部回流区及角回流区，主、预燃级气流的相互耦合过程分为独立射流、气流掺混和气流合并三个阶段。主燃级旋流数对头部流场结构影响较大，随主燃级旋流数增大，主、预燃级气流耦合作用减弱，回流区分布形态发生较大变化，新的流场结构特征为中心主回流区范围明显收缩，端部回流区向下游延伸，在主、预燃级之间剪切层形成较长回流区。针对该中心分级燃烧室头部，主、预燃级气流由耦合流动变为解耦流动的临界主燃级旋流数为0.8~1.0。

Abstract:

In order to investigate in-depth the flowfeld characteristics of a centrally-staged combustor， PIV test was carried out to study the characteristics of cold flowfield in a centrally-staged combustor dome. Emphasis is mainly focused on the characteristics of flowfield structure and the impact of swirl number of main stage on the flowfield. Experimental results show typical flowfield of the centrally-staged combustor dome includes a main recirculation zone， a smaller tip recirculation zone and a corner recirculation zone， and the interaction between the main stage flow and pilot stage flow is divided into three stages： independent jet， airflow mixing and airflow merging. The swirl number of main stage has a significant impact on the flowfield. As swirl number of main stage increases， the coupling effect between the main stage flow and pilot stage flow becomes weak， the recirculation zone changes greatly. The main recirculation zone shrinks obviously and the tip recirculation zone extends downstream forming a longer recirculation zone in the shear layer between the main stage and pilot stage. For this centrally-staged combustor dome， the critical swirl number of main stage， in which the main stage flow and pilot stage flow change from a coupled flow to a decoupled flow， is between 0.8 and 1.0.