The experiment choose TiO2 which had good following performance as well as scattering property.The flowfield of the single expansion ramp nozzle (SERN) under different pressure ratios was researched by particle image velocimetry (PIV) and numerical method.In the experiment

the structure of the flowfield

the pressure on the upper expansion wall

the velocity vector

and so on have been successfully obtained.From the processed images

the shock and expansion wave can be observed clearly

and the velocity at the outlet has been further analysized.The experimental data agreed very well with the data from the computational fluid dynamics (CFD).Therefore

the accuracy and reliability of the PIV experiment and the CFD result were both validated.