科研之友
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摘要
Acoustic damping induced by a gas-liquid scheme injector is investigated numerically for acoustic stability by adopting an acoustic analysis. The injector consists of four parts of a main cylindrical passage, an inlet blockage, an induction bulge, and a recess at the injector outlet. Purely acoustic behavior in the combustor with a single injector is investigated for acoustic tuning of the injector and the effect of each part of the injector on acoustic damping is studied for high-temperature condition. Sinusoidal and short impulse acoustic oscillations are excited. Damping capacity of the injector is evaluated by the quantitative parameter of damping factor. From the numerical results, it is found that each injector has its own tuning length for maximum damping. An induction bulge and a recess deform the wave-form inside the injector appreciably near the inlet and the outlet, respectively. The deformation of a half-wave form makes the tuning length longer. All the wave-forms inside the optimally tuned injectors show similar forms to that of a half-wave. All the injectors have the same damping mechanism as that of a half-wave resonator. The smaller the amplitude level of the wave is at the injector outlet, the larger damping is induced by the injector. As a recess increases, both the optimal tuning length and the maximum damping factor increase. For application of the injector to an actual combustor, the optimal tuning length needs to be corrected considering high-speed flow inside the injector and high-temperature field in a chamber.
- 出版日期2014-9
