Numerical Simulation Of Kerosene Spray Combustion In The Dump Advanced Trapped Vortex Combustor

Advanced Trapped Vortex Combustor is a new concept Aircraft engine combustor proposed by the Ramgen company, Stable combustion is achieved by the use of low speed recirculation zones which provide the condition for ignition sources and igniting the high speed mainstream in cavity. The combustion chamber has a unique flame stability, high efficiency, simple structure and low pollutant emission, recently attracted much attention and research. In this paper, based on this, put forward the dump Advanced Trapped Vortex combustor, and numerical simulation software FLUENT was applied to systematic study the cold flow field and the thermal kerosene spray combustion.Under cold conditions, to determine the optimal length of front boss to achieve stable combustion, we studied the flow field and the total pressure loss coefficient of different front boss length of the combustion chamber. The results show that the front boss length had a great influence on flow field distribution of the combustion chamber.With the increase of L, the number of vortex and vortex core in the cavity are changed,however, the front boss length has little effect on the total pressure loss coefficient of combustion. The influence of three kinds of turbulence models on the combustion chamber flow field is analyzed, and the realizable k-epsilon turbulent model is more reasonable to predict the distribution of the flow field in the combustion chamber. The cold flow field in combustion chamber with the opening angle of the posterior bluff body and its opening angle and the combustion chamber with the flow guide vane and its horizontal position were studied, It is concluded that the vortex in the cavity of the open cavity of the posterior bluff body is outward shifted and is connected with the vortex in the back flow region of the posterior bluff body, the impact of opening angle is not obvious. The concave cavity vortex with a flow guide plate is mainly formed after the flow guiding plate and the transverse position of the flow guiding plate has great influence on the flow field distribution in the cavity.Under a hot state established kerosene spray combustion physical model, using the appropriate turbulence model, non-premixed combustion model and discrete phase model, CO generation model and detailed chemical reaction mechanism of combined combustion chamber of kerosene spray combustion numerical simulation. By using the Simple solution method, using two order upwind convection phase, the near wall regionusing the standard wall function.Analysis of the front boss length, inlet air temperature,turbulence model choice, the main fuel nozzle injection speed, main and auxiliary fuel nozzle flow distribution, vertical position of the auxiliary nozzle and the deflector lateral position effect on the combustion performance. The results show that the optimal L value is 30 mm. The inlet temperature of great effects on combustion performance,improve the inlet flow temperature for atomization of kerosene gasification, but the combustion efficiency decreases, the export of high temperature region growing.The realizable k-epsilon turbulent model and non-premixed combustion model(PDF) is suitable for the simulation of combustion chamber. The opening angle of the bluff body is 15 degrees. It is beneficial to improve the combustion efficiency of the combustion chamber to improve the injection speed of the main fuel injection nozzle; The temperature field and the distribution coefficient of the outlet temperature of the recirculation zone after the cavity and the posterior bluff body are obviously different,So it should be reasonable distribution of the main sub nozzle of the fuel flow; The vertical position of the auxiliary nozzle and the transverse position of the flow guiding plate have great influence on the temperature field and the discharge of the combustion chamber. Kerosene spray combustion flow numerical simulation results of the dump advanced trapped vortex combustion chamber are analyzed and compared, indicating that the physical model established in this paper can well simulate the combustion chamber of kerosene spray combustion performance and provide a reference for further advanced trapped vortex combustion chamber design and improvement.