本文以固体火箭发动机尾焰这种高温、高速、高颗粒数密度及强背景噪音含颗粒射流为研究对象，对适用于此环境下的颗粒速度和粒径测量技术进行了研究，发展了适用于大粒径颗粒速度测量的粒子轨迹法，适用于浓密小颗粒速度测量的调制激光互相关测速法，并探讨了基于消光法进行颗粒粒径测量时复散射效应的影响。 在固体火箭发动机尾焰流场中同时存在浓密的小尺寸颗粒和稀疏的大尺寸颗粒。针对大尺寸颗粒亮度高、易于分辨、速度高的特点，本文提出采用高速摄像的方法，对流场中大颗粒进行粒子轨迹法速度测量。本文提出了确定轨迹长度的一维拟合算法，并采用计算合成图像检验了该算法的效率及精度，证实该算法得到的粒子轨迹长度不确定性为亚像素尺度。利用发展的粒子轨迹法测速技术对某固体火箭发动机尾焰流场进行了实验测量，获得了尾焰流场中大尺寸颗粒的全场速度信息，揭示了尾焰流场中大颗粒运动特征。 对于固体火箭发动机尾焰流场中浓密的小颗粒速度的测量，针对发动机尾焰中颗粒数密度高，并且存在高背景噪音光的特点，本文在传统互相关测速技术基础上提出了调制激光互相关测速技术，该技术中对入射激光进行光强调制，并对接收到的颗粒散射光信号进行带通滤波降噪后再进行互相关计算以得到颗粒通过两探测区所用时间。对速度在 1 × 10?3 m/s 到 3 × 102 m/s 之间的颗粒运动进行的实验测量表明该方法可以有效消除背景噪音及颗粒高浓度的影响，在所测试的速度范围内，该方法的最大测量误差不超过 5%。为探究复散射效应对消光法粒径测量的影响，本文采用已知粒径的标准颗粒，进行了变颗粒粒径、颗粒数密度及光程的透射率测量实验，并在实验中严格限制探测器接收角及保持颗粒悬浮以消除颗粒沉降对透射率的影响。实验结果表明当颗粒群光学厚度大于 2 时，利用消光法进行粒径测量时需要考虑颗粒的复散射效应。本文结合多通量理论模型，定量分析了复散射效应对消光法测量颗粒粒径的影响。基于此结果，利用双波长消光法对某固体火箭发动机尾焰中颗粒粒径进行了测量，获得了该尾焰中颗粒的粒径分布。

The plumes of Solid Rocket Motors (SRMs) are typically high-speed high-temperature particle-containing jets with high particle number density and intense background noise. This thesis reports techniques developed for measuring the velocities and sizes of particles in the plumes of SRMs, including a Particle Streak Velocimetry (PSV) method for measuring the velocities of sparse, large-sized particles in the plumes and a Modulated Laser Cross-Correlation Velocimetry (MLCCV) method for measuring the velocities of dense, small particles. The effects of multiple scattering on the laser extinction method for measuring particle sizes of dense particle clouds were also analyzed.In the plumes of SRMs, there are simultaneously dense, small particles and sparse, large particles. To take advantages of the high-brightness and high-speed of large particles, we measured the velocity of large particles in the plumes using particle streak velocimetry (PSV) by direct imaging with high-speed cameras. For PSV, a one-dimensional fitting algorithm was proposed to determine the lengths of particle trajectories on the images of plumes. Tests with synthetic images of particle trajectories showed that the algorithm is efficient in computation and is of sub-pixel accuracy in the trajectory lengths obtained by the measurements of the plume of a full-scale SRM using the PSV developed in this thesis provided the full velocity field of large particles in the plume and revealed important flow characteristics of large-particles in the plume of the SRM. To measure the velocities of dense, small particles in the SRM plumes of SRMs, one must take into account of the high particle number density and the intense background noise light in the SRMs plume. To that end, a modulated laser cross-correlation velocimetry (MLCCV), based on the traditional cross-correlation velocimetry, was proposed. In MLCCV, the incident laser beam is modulated such that its intensity varies at a given frequency. This modulated laser incidence is scattered by the particles in the plume and the scattered lights at two closely separated locations are recorded by two detectors. The received signals are band-filtered and then cross-correlated to obtain the time-lag between them, which is the time for the particles to pass through the two detection regions.Experimental tests using particles with velocities in the range between 1 × 10?3 m/s and 3 × 102 m/s indicated that the MLCCV method effectively removed the effects of high background noise light and performed well in situations with high particle number densities. The measurement uncertainties of the MLCCV are less than 5% within the entire range of velocities tested. To quantify the effect of multiple scattering on the laser extinction method for measuring particle sizes of dense particle clouds, a series of measurements of laser transmittance through clouds of standard particles of various known sizes, number densities and optical path lengths were carried out, all under the condition that the acceptance angle of the detector was limited to nearly zero and the particle settling by gravity was eliminated to maintain constant particle number densities in the experiments. The results showed that when the optical thickness of the particles is greater than 2, the multiple scattering effect of the particles must be considered when measuring the light extinction by particle clouds. Combined with a multi-flux model, the effects of multiple scattering on the laser extinction method for particle size measurement were analyzed quantitatively. Based on this result, the size of particles in the plume of a testing SRM was measured using the dual-wavelength extinction method, and the particle size distributions of the plume were obtained.