中心分级多点直喷燃烧室冷态流动特性研究

Non-Reaction Flow Characteristic of Concentric Staged Multi-Point Direct Injection Combustor

关键词:  燃烧室  中心分级  多点直喷  流动特性  周期性边界  发散冷却

Key words:  Combustor  Concentric staged  Multi-point direct injection  Flow characteristic  Periodic boundary  Effusion cooling

摘要:

为了探究中心分级双旋流多点直喷燃烧室冷态流动特性，采用数值计算和实验方法进行研究，建立了回流区主要特征参数定量描述方法，分析了主/副模旋流的发展过程，并获得了头部之间相互干涉以及冷却空气与旋流空气之间的相互作用规律。结果表明：在中心分级双旋流矩形燃烧室（模型A）中形成了稳定的中心回流区，回流区扩张角为30°，有利于小工况下的火焰稳定；在带周期性边界的燃烧室（模型B）中，头部之间的相互干涉导致角回流区涡心位置向下游移动，涡心间距减小，角回流区尺寸明显增大，抑制了中心回流区的发展，最终形成了两个较小的中心回流区，一次回流区扩张角减小为20°；在带发散小孔冷却的燃烧室（模型C）中，冷却空气抑制了角回流区的发展，在中心截面角回流区基本消失，形成了尺寸更大中心回流区，回流区扩张角增大至35°。

Abstract:

The non-reaction flow characteristic of the concentric staged dual swirl multi-point direct injection combustor was investigated by numerical simulation and experiments. A quantitative description method of the main characteristic parameters of the recirculation zone was established. The development process of pilot/main module swirl flow in the combustor was analyzed. The mutual interference between the domes as well as the interaction between the effusion cooling air and the swirling air were obtained. According to the results， a stable central recirculation zone （CTRZ） is formed in the concentric staged dual swirl rectangular combustor （model A）， and the expansion angle of CTRZ is 30°， which is beneficial to the flame stabilization under the low conditions. In the combustor with periodic boundary condition （model B）， the vortex center in the corner recirculation zone （CORZ） moves downstream because of the mutual interference between domes. The size of CORZ significantly increases while the vortex center distance is decreased， which inhibits the development of the CTRZ. Therefore， two smaller CTRZs are formed and the expansion angle of the first CTRZ is reduced to 20°. In the combustor with effusion cooling holes （model C）， the effusion cooling air suppress the development of the CORZ， which disappears at the central section. A larger CTRZ is formed and the expansion angle of the CTRZ increases to 35°.