Investigation of micro vortex generators on controlling flow separation over SCCH high-lift configuration

For the problem that the flow separation on the flap lowers the aerodynamic performance of high lift system,an investigation was carried out on using micro vortex generators(VGs) to control the separation on flap of the swept constant chord half-model(SCCH) high-lift configuration,at a small to medium angle of attack,by experimental and numerical methods.The basic flow characteristics of SCCH landing configuration were analyzed by using numerical method to provide required information for the design of micro VGs.Then,by keeping the cruise configuration intact,the preliminary design procedure and design methods of micro VGs were established.In addition,the micro VGs were designed.The effects of VG's arrangement and geometric parameters,such as the arrangement mode,chordwise position,arrangement angle,height and spanwise distance,on controlling efficiency were investigated by using numerical method.Then the parameters of preliminary VGs were adjusted as the basis configuration for wind tunnel test.The experiments were accomplished in NH-2 wind tunnel for validating the numerical method,as well as obtaining the design principles and methods of micro VGs.The parameters of VGs were also optimized based on the experiments.The experimental results showed that the numerical design method can serve as an efficient and accurate design tool.The lift and drag were increased by 10% and 14%,respectively in landing state,which satisfied the requirements for landing.Finally,it was concluded that the established design principles and methods for micro VGs in this investigation can be used in engineering application.

Effect of the micro vortex generator on the characteristics of vaporized RP-3 kerosene combustion in supersonic flows

To investigate the characteristics of vaporized RP-3 kerosene combustion in a scramjet combustor enhanced by the micro vortex generator(MVG),a series of experiments are carried out based on the advanced combustion diagnosis technique.The high-enthalpy incoming flow is accelerated to supersonic through a Mach 2.52 nozzle,the total pressure and temperature of which are 1.6 MPa and 1486 K,respectively.The effect of MVG on the ignition process,flame distribution,and combustor pressure along the bottom wall is well revealed,and the effects of the position and number of MVGs on stable combustion performance are analyzed.The results indicate that the development processes of the initial flame kernel with and without an MVG during ignition process show a similar behavior.The installation of an MVG can lift the shear layer,promote the penetration of flame deeper into the mainstream,and expand the area of the reactive region.Reducing the distance between the MVG and the injection position and increasing the number of MVGs are regarded as effective ways of improving the mixing degree of fuel and air with a resultant intensification of chemical reactions and flame luminescence.The effect of mixing and subsequent combustion is enhanced by shortening the distance between the MVG and the injection position.As the layout schemes of the MVG vary,the pressure distribution between the injection position and the leading edge of the cavity changes considerably,while that in the cavity remains almost constant.Increasing the number of MVGs is also beneficial for improving the premixed degree of fuel and incoming flow and results in more violent chemical reactions downstream of the cavity.