火焰稳定器后动态流场研究

南京航空航天大学

硕士学位论文

火焰稳定器后动态流场研究

姓名：刘宜临

申请学位级别：硕士

专业：工程热物理

指导教师：何小民

20090101

南京航空航天大学硕士学位论文

摘要

加力燃烧室火焰稳定器的火焰稳定性和燃烧效率除了依赖燃气浓度分布以外，很大程度上决定于钝体后流体的流动特性，目前，几乎所有关于燃烧稳定问题的分析都是从时均场角度进行分析的。而火焰稳定器后的流场是一个典型的钝体绕流，这里面的二次回流，旋转破碎的现象十分明显。了解稳定器后近尾迹瞬态流场的详细特性，对于认识燃烧现象的本质很有帮助。

本文先应用压力传感器对V型稳定器、双V稳定器、薄膜蒸发稳定器、吸入式稳定器、和各种不同槽宽和顶角的V型钝体在不同流速进行了涡脱落频率测量。结果表明相同槽宽是决定漩涡脱落频率的唯一几何条件；随着来流速度的增大稳定器后漩涡脱落频率不断增大。

在动态频率测量的基础上，本文在利用高速摄影仪和流场显示技术，对以上各种稳定器后动态冷态流场进行了拍摄。分析了各个稳定器的瞬态流场特点。并和计算机仿真结果进行了对比和验证。掌握了以上各种稳定器的动态流动特征并对其动态流动机理进行了分析，从非定常观点提出了稳定器稳焰机理。

本研究一方面为稳定器的设计提供参考和依据，另一方面对我们了解稳定器后近尾迹瞬态流场的详细特性具有极大的帮助。研究为下一步开展火焰稳定器后动态燃烧场的研究奠定了基础。

关键词：火焰稳定器非定常冷态流场涡脱落

火焰稳定器后动态流场研究

Abstract

Besides gas concentration distribution, the flame stability and combustion efficiency of flame holder also depend on flow behavior of blunt body and fluid. Nowadays, almost all of combustion stability analysis emphasize on time-averaged. However, the flow field behind flame holder is a typical flow around blunt body, and the rotation crush of secondary back-flow here is very clear. So to have a general understanding of detailed features in near-wake transient flow field behind flame holder is very helpful for us to know the essence of Combustion Phenomena.

Pressure sensor is used to measure vortex shedding frequency at difference flow speed in

V-gutter flame holder, double V-gutter flame holder, film evaporation flame holder, suction flame holder, and V-gutter blunt body with different gutter width and angles. It is showed that the same gutter width is the only geometric condition to determine vortex shedding frequency, and the vortex shedding frequency behind flame holder is increased by the increasing flow speed.

Based on dynamic frequency measurement, using high-speed camera and the display technique for flow field, this article records the dynamic cold flow fields behind the mentioned flame holders, analyzes the features of transient flow fields, and also takes a comparison and verification with the results of computer simulation research. With the features of dynamic flows in the mentioned flame holder, as well as the analysis of dynamic flow mechanism, by taking instantaneous viewpoint, this article brings forward the flame stability mechanism in flame holder.

As a reference for design of flame holder, this research is very helpful for us to have knowledge of detailed features in near-wake transient flow field behind flame holder, and also lays a good foundation for the further research of dynamic combustion field behind flame holder.

Key words: flame holder, instantaneous, cold flow field, vortex shedding