中文摘要：

选取了跟随性能以及散射性能都上佳的二氧化钛粒子,利用了粒子图像测速仪（particle imagevelocimetry,PIV）对不同落压比下的非对称喷管（single expansion ramp nozzle,SERN）流场进行了测量,成功获取了相应流动结构,以及沿程上壁面压力分布和速度场等.在测得的图像中,可以清晰地观察到由于过膨胀产生的激波与膨胀波系,并进一步获得出口速度分布.运用计算流体动力学数值模拟方法,对实验状态下的非对称喷管进行了模拟.对比结果发现：PIV实验测得流场结构能很好地与其吻合,这互相验证了CFD计算和PIV实验的正确性及可靠性.

英文摘要：

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.