燃烧室内自激励振荡燃烧的数值研究

采用数值方法研究了Langhorne型燃烧室内自激励燃烧驱动振荡的不稳定现象．应用非稳态雷诺平均法、雷诺应力紊流模型和涡团耗散燃烧模型,捕获了该类型燃烧室内两种当量比条件下的不稳定燃烧特性．数值模拟结果给出振荡燃烧发生时燃烧室内的压力振荡频率和幅值,并同实验结果进行了比较．证明了在两种当量比下分别存在着“强振荡”和“弱振荡”,并给出了两种当量比条件下不稳定燃烧时火焰的周期影像,详细分析了振荡发生时燃烧室内的火焰发展情况．

Numerical Study on Self-Excited Oscillation Combustion in a Combustor

Computational fluid dynamics (CFD) technology is used to study self-excited combustion driven instability in Langhorne tube combustor. Reynolds-averaged approach, Renolds stress model and eddy dissipation model are used to capture the characteristics of the combustor in two types of air/fuel ratios. Detailed results such as frequencies, amplitudes of pressure and outlet velocity are given when oscillation occurs. Numerical results are measured by experiment data , and the difference between predicted and measured frequency is discussed. Periodic images of flame in two air/fuel ratios are given, and the development of flames in combustor when oscillation occurs is analyzed. The existence of two types of self-excited oscillation,which were named "weak buzz" and "established buzz" is proven.