Non-adiabatic flamelet modeling for combustion processes of oxy-natural gas flame

In order to realistically predict the combustion characteristics of the oxy-fuel flame, the present study employs the non-adiabatic flamelet approach. In this combustion model, the detailed equilibrium chemistry is utilized to accurately account for the thermal dissociation as well as to properly include the radiative cooling effects on the detailed chemistry. Numerical results indicate that the present approach has the capability to correctly capture the essential features and precise structure of the oxy-fuel flames. In this work, the detailed discussion has been made for the characteristics of oxy-fuel flames, the capability and defect of the present approach and also uncertainties of experimental data.     

On the method for hot-fire modeling of high-frequency combustion instability in liquid rocket engines

This study presents the methodological aspects of combustion instability modeling and pro-vides the numerical results of the model (sub-scale) combustion chamber, regarding geometrical dimensions and operating conditions, which are for determining the combustion stability boundaries using the model chamber. An approach to determine the stability limits and acoustic characteristics of injectors is described intensively. Procedures for extrapolation of the model operating parameters to the actual conditions are presented, which allow the hot-fire test data to be presented by parameters of the combustion chamber pressure and mixture (oxidizer/fuel) ratio, which are customary for designers. Tests with the model chamber, based on the suggested scaling method, are far more cost-effective than with the actual (full-scale) chamber and useful for injector screening at the initial stage of the combustor development in a viewpoint of combustion instabilities.     

增压锅炉烟气发生器燃烧流场与污染排放数值分析

为了考察设计方案中增压锅炉烟气发生器的阻力大小及流场条件能否满足系统设计要求,采用FLUENT程序,对增压锅炉烟气发生器设计结构方案的燃烧流场及阻力进行了数值分析,同时考察了发生器的污染物排放性能。数值模拟时采用了RNGk-ε湍流模型、P-1辐射模型、液体燃料喷雾燃烧过程的颗粒轨道模型和PDF燃烧模型,对设计方案的压力场、温度场及NOx排放进行分析,得到了设计方案的阻力特性、温度分布和排污特性。结论表明:该方案的阻力大小及出口温度能够满足设计要求。该工作为优化烟气发生器结构和污染控制具有重要的指导意义。