Research On Numerical Simulation Of Flow Structure And Flame Stabilization In A Novel Combustor With Slotted Swirler

Maintaining flame stabilization is the fundamental condition to ensure the regular operation of combustors. Once fuel couldn't be burnt in a stable state after being ignited,phenomenon such as blow off or flashback may come out. Swirl flow is one of the most effective methods to ensure flame stabilization and swirler is the source of generating swirl flows. Recirculation zone is formed when air passes through swirler and fuel becomes mixed fully in the recirculation zone,where stable and efficient combustion occurs.The model we focus in the present paper is a novel swirler——Slotted Swirler. Compared with traditional axial swirler,the slotted swirler has six slits around the nozzle. And the slits play a vital role in optimizing structure of recirculation zone and intensifying combustion. Numerical simulations for non-reacting flow and non-premixed combustion in combustors with slotted swirler(CSS) and traditional swirl combustors(TSC) have been done by using Fluent,then velocity field and temperature field are compared. For slotted swirlers,size of the slits and position of the slits are in consideration in terms of its effects on flow and combustion. The numerical results illustrate that:(1) For low swirl flow and high swirl flow, after applying slits to swirlers,the length of recirculation zone and the velocity in the recirculation zone decrease. Turbulence intensity increases in the outlet of slits. And temperature in same position in the main combustion area grows.(2) For low swirl flow generated by slotted swirler,,the temperature is relatively lower and distributes uniformly near the outlet of swirler. The same applied to the 45°slotted swirler and 60°slotted swirler. For slotted swirlers with angle of 40°,50°and 55°,there exists obvious high temperature zone near the outlet of slits,which is considered as the source of ignition.(3) The length of recirculation zone stays the same when the position of the slits moves. When the slits stay in the middle,the temperature in the main combustion area is relatively higher and the temperature near the wall keeps the same wherever the slits are. The larger the size of the slits is, the shorter the length of recirculation is. When the slits are small,the high temperature region is along the outlet of swirler to the wall. Once the slits become larger,this area has a massive distribution.