Investigation On PIV Velocity Measuerment Technology Of Supersonic Flow Field

Aiming at the inflow condition of flight Mach 5.5,the entrance to the flow Mach 2.52,total temperature 1486 K,total pressure 1.6MPa,the paper studies flow field velocity measurement of the scramjet supersonic combustion.The particle concentration,the uniformity of particle seeding,the interference of high temperature radiation flame and other issues were solved.PIV,high-speed photography and schlieren were used to investigate the flow field velocity measurement of high total temperature and the flow field velocity field measurements of supersonic combustion,and velocity flow field by extracting the speed types of X,Y cross sections of different times and different positions was analyzed.Firstly,experimental research on flow field velocity measurement of high total temperature by using PIV technology was conducted.The particle concentration,the uniformity of particle seeding and other issues were solved,the uniformity of particle seeding were achieved by adding nanoparticles to alcohol,the problem of particle concentration by adjusting the ratio of nanoparticles and alcohol continuously was solved.It shows that particles concentration of alcohol is crucial,it will affect the result of PIV numerical,such as,accuracy and uniformity of flow field velocity;Mainstream area rate of high total temperature velocity field measured by this method is 1200m/s magnitude;velocity flow field by extracting the speed types of X,Y cross sections of different times and different positions was analyzed,boundary layer velocity present gradient distribution,the speed of 2mm distance away from the wall is 500m/s magnitude.Mainstream area rate present different levels in the Y direction.Secondly,experimental research on flow field velocity measurement of supersonic combustion by using PIV technology was conducted.The particle concentration,the uniformity of particle seeding,the interference of high temperature radiation flame and other issues were solved.The uniformity of particle seeding was achieved by adding nanoparticles to alcohol,the problem of particle concentration by adjusting the ratio of nanoparticles and alcohol continuously was solved,the problem of high temperature radiation flame by adding filters in front of the camera lens was solved.For fuel injection equivalent ratio and injection location had carried on the experimental study,velocity flow field of supersonic combustion were measured,injection location away from the leading edge of the cavity was 30 mm,the equivalent ratios in which of ethylene were 0.26 and 0.36;injection location away from the leading edge of the cavity was 10 mm,the equivalent ratios in which of ethylene were 0.26 and 0.36;injection location away from the leading edge of the cavity were 30 mm and 10 mm at the same time,the equivalent ratio in which of ethylene was 0.36.Velocity flow field by extracting the speed types of X,Y cross sections of different times and different positions was analyzed.Finally,the impact of the ratio of ethylene injection on the structure of the flow field was analyzed,the impact of the injection location of ethylene on the structure of the flow field was analyzed,the impact of the injection location of ethylene and the ratio of ethylene injection on the size of jet wake zone,the position of the jet wake zone,the speed fluctuations of jet wake zone,the thickness of boundary layer,boundary layer velocity,flow field continuity,flow lines and so on,based on the speed cloud and X,Y cross sections speed types.