Velocity Measurement Investigation of Rarefied Flow Field by Pulse Electron Beam Fluorescence Technique

The PEBF(pulse electron beam fluorescence) technique is a nonintrusive method for velocity measurement in rarefied flow field. In this paper, some experiments were implemented to measure radial flow velocity distribution at a cross section 150 mm away from the nozzle exit under the condition that P₀ is 2 MPa and T₀ is 650 K in a Φ0.3 m low density wind tunnel with a Mach 12 contoured nozzle. The repeatability deviation of the 7 experiments at each measurement point was about 10% and the maximum relative uncertainty was 4%. The deviation of average velocity at the center position was only 1%, compared with the average value of 4 velocities obtained by PEBF measurement method, Pitot tube measurement method, Rayleigh scattering measurement method and N-S/DSMC numerical simulation method. The above results show the reliability of PEBF technique in measuring flow velocity.