Design Of Supersonic Combustion Spray Gun Test Rig And Characteristic Analysis Of It's Flame Flow

Thermal barrier coatings(TBCs)are the preservative technology of advanced aeroengine and the critical insulating techcology in the international aeronautics program.Therefore,TBCs have been widely used as components in hot end of aeroengine.Due to their complex structures and severe service circumstances coupled with thermal,mechanical and chemical loading,TBCs occur spallation failure easily.Hence,it's very difficult to undersand the failure analysis of TBCs by traditional experimental methods such as tensile test?bending test.Through developling the device to simulate the actual service conditions of TBCs to undesantd the failure analysis of TBCs is important.And the core tecology is the secret of turbine engine power.In this paper,the development process of supersonic combustion spray gun to simulate the service circumstances coupled with thermal,mechanical and chemical loading of TBCs will be introduced in detail.This paper also caculate the flame flow characteristic in supersonic combustion spray gun through the CFD software.The main contents in this thesis are listed as follows:Firstly,according to the general principles of nozzle design,the supersonic combustion nozzle that exit Mach number is 2 has designed.Convergent curve uses quintic curve,in addition,throat and expansion curve use circular curve.The whole design process is made by Matlab programming to realize.At the same time,the CFD software has been used to simulate the vecolity?temperture?pressure and Mach number distribution.The simulation results show that exit Mach number is 1.92,which is close to 2,has proved the feasibility of supersonic combustion nozzle.Finally,selecting an appropriate process flow scheme to machines the nozzle.Secondly,the gas path system?fuel system and power feeding system have been designed.The gas path system includes oxygen gas path and air gas path.The oxygen gas path provides oxidant to spray gun and the air gas path provides cooling air to surface cooling and back cooling of sample.And a small part of air participates in the combustion process.The fuel system inlcudes pressure adjusting gas path by controlling nitrogen pressure and kerosene supplying path.The kerosene pressure into spray gun is adjusted by controlling the pressure of nitrogen into kerosene tank.By this means,the exit Mach number is changed within a narrow range.The kerosene supplying path provides kerosene to spray gun and power feeding system provides erosion particles and CMAS to test rig.Thirdly,the geometric model of supersonic combustion nozzle was established and appropriate combustion model was choosed.Then the flame flow characteristic was analyzed.The simulated results show that the maximum temperature is affceted by the mass flow rate n of oxygen and kerosene.And the total mass flow rate of kerosene and oxygen Q has little impact to the maximum temperature of the flame flow.The velocity of flame flow is affceted by the pressure into the spray gun.The higher pressure into the spray gun is the faster velocity of flame flow is.When pressure into the spray gun is 0.8 MPa,the speed of flame flow doesn't reach the supersonic speed.But when pressure into the spray gun is 1.2 MPa,the speed of flame flow reach the supersonic speed and the exit Mach number is 1.33.Compared to the photograph under actual parameter conditions,it can be seen visually that there is no phenomenon of supersonic flow.