Research On Performance Of Oblique Flow Trapped Vortex Combustor In Turboshaft Engine

Based on the concept of trapped-vortex stabilized flame,oblique flow trapped vortex combustor(OFTVC)is proposed to apply in turbo-shaft aero-engine.Both flame stability,combustor radial space and axial length are considered.Compared with reverse flow combustor,OFTVC can reduce liner cooling area;compared with straight flow combustor,OFTVC can reduce axial length.Typical high-temperature-rise combustor parameters of turbo-shaft aero-engine are used in design in this paper.Combustor preliminary design,numerical simulation and experimental research are carried out.This paper firstly introduces basic principle of oblique flow trapped vortex combustor briefly,and then finishes structure parameter and flow distribution calculation.After model builded,numerical simulation study is carried out.The calculation results show: flow characteristics of typical plane satisfy the design requirements.Cavity flow structures are less sensitive to inlet conditions like inlet velocity and temperature,and the cores of main vortex are located at the same position.Experimental investigation under normal pressure condition is conducted.The results reveal:(1)Total pressure loss coefficient increases with increase of the inlet velocity,while the flow resistance coefficient remains constant(2.4).(2)Under normal temperature condition,ignition fuel air ratio and lean blowout fuel air ratio remain stable when inlet velocity increases from 30m/s to 50m/s.Ignition fuel air ratio changes from0.0085 to 0.009,and lean blowout fuel air ratio is about 0.0045.Ignition fails when inlet velocity is60m/s.(3)When pressure swirl atomizers are applied in main flow,combustion efficiency decreases with increase of the inlet velocity.Rapid increase of inlet velocity leads to rapid decrease of combustion efficiency.Combustion efficiency increases with the inlet temperature and combustor fuel air ratio.In the experiment,aerodynamic multi-holes fueling scheme has better combustion efficiency than pressure swirl atomizer scheme.(4)Outlet temperature distribution factor(OTDF)increases with increase of the inlet velocity.When inlet velocity is less than 60m/s and inlet temperature is 443 K,OTDF value is less than 0.25.OTDF decreases when the inlet temperature and combustor fuel air ratio increases.