中心分级燃烧室流场特性研究

STUDY OF THE FLOWFIELD CHARACTERISTICS OF A CENTRAL STAGED COMBUSTOR

王泽

11849103

硕士

航天工程

甘晓华

2020-05-28

2020-07-13

哈尔滨工业大学

深圳

本论文针对中心分级燃烧室的流场特性开展了数值研究。通过基于雷诺应力平均的数值方法，研究了主燃级旋流器叶片偏转角、预燃级套筒出口扩张角以及台阶高度对中心分级燃烧室流场特性的影响。通过基于大涡模拟的数值方法，对中心分级燃烧室动态流场特性及流场形成机制进行了研究。本论文主要结论如下： (1)在主燃级叶片角和燃烧室出口耦合影响下，流场下游存在的低压区域对预燃级流动影响明显，主燃级叶片角增大，预燃级气流张角减小。 (2)预燃级套筒扩张角主要决定了预燃级气流的初始扩张角，从而影响主燃级气流和预燃级气流汇合的位置，但对流场整体的影响较小。 (3)台阶高度影响主燃级和预燃级气流的耦合作用，台阶高度较小时，主燃级气流与预燃级气流快速汇合；当台阶高度增大到一定程度，预燃级气流只有部分与主燃级气流汇合，另一部分受下游低压区域的影响流向燃烧室出口。 (4)简化几何构型的大涡模拟计算表明，中心分级燃烧室理论上存在五种流场结构，其中“圆形主回流区”型、“U状主回流区”型、“双主回流区”型在模型燃烧室中已捕捉。\par (5)流场上游正向流动的气流与回流气流存在较强的剪切和对冲作用，形成大量漩涡结构。预燃级气流在流场中十分不稳定，流动方向多变。燃烧室出口低压区主要是由于气流加速流动及余旋流动形成，低压越强对上游预燃级流动影响越显著。

In this paper, a numerical investigation is carried out to study the characteristics of the flow field in the centrally staged combustor. Through the numerical method based on the Reynolds averaged N-S equation, the effects of the main vane angle, the expansion angle of the pilot's sleeve, and the lip height on the flow characteristics of the centrally staged combustor were studied. Through the numerical method based on large eddy simulation, the dynamic flow field characteristics and flow field formation mechanism of the centrally staged combustor were studied. The main conclusions of this paper are as follows: (1) Under the coupling effect of the main vane angle and the contractive combustor outlet, there is a low-pressure area downstream of the flow field, which has a significant effect on the pilot airflow. The main vane angle increases while the pilot airflow opening angle decreases. (3) The lip height affects the coupling effect between the main and the pilot airflow. When the lip height is short, the main airflow and the pilot airflow merge quickly. When the lip height increases to a certain extent, a part of the pilot airflow is merged with the main airflow, and the other part flows to the outlet of the combustor under the influence of the downstream low-pressure area. (4) A large-eddy simulation study on the flow field characteristic of a simplified central staged combustor shows that there are theoretically five flow field structures in the centrally staged combustor, including "circinal primary recirculation zones," "U-shaped primary recirculation zones," and "dual primary recirculation zones," which have been captured in the model combustor. (5) There are intense shearing and countering effects between the axial airflow and the recirculated airflow upstream of the flow field, forming a chain of vortex structures. The pilot airflow is very unstable with its flow direction varying with time rapidly. The low-pressure area near the contractive outlet of the combustor is mainly due to the accelerating effect and the swirl effect of the airflow. The lower the pressure is in the low-pressure area, the more significant the impact on the upstream pilot airflow.

中心分级燃烧室 流场特性 数值模拟 大涡模拟

centrally staged combustor flow field characteristics numerical simulation large eddy simulation

中文

联合培养

南方科技大学

王泽. 中心分级燃烧室流场特性研究[D]. 深圳. 哈尔滨工业大学,2020.