Analysis and Modeling of Transport Phenomena in a Complex Multiphase Flow by High Resolution Opt-electrical Measurements

围绕阐明多相流中输运过程的复杂机理，开展了一系列关于新型湍流模型数值预报的分析和实验研究，即离散多相流的多尺度数值预报，高分辨率激光传感系统仪器的研制，以及利用在线计算网络的信号处理系统。激光多普勒技术被扩展到利用阴影成像来捕捉颗粒的形状，我们称之为阴影多普勒测速技术。将阴影多普勒方法应用于受限射流中的流场，其中非球形颗粒由于颗粒取向引起的升力比球形颗粒分散得更多。对于气泡流动的测量，在…中评价分析使用了更多的高速数码相机，时间分辨率更高。对剪切层中气泡的变形和行为进行了实验研究。用数字粒子图像测速仪分析了气泡边界附近的流动结构，并利用红外阴影成像技术对激光诱导荧光粒子和瞬时形状进行了补充。指出气泡诱导的湍流主要由气泡的摆动和尾流中诱导的涡量所决定，发展了一种测量流场中第三速度分量的流粒子图像测速仪，并在二维斜喷流中对测量误差进行了评估。根据这些实验结果，结合多时间尺度对湍流多相流进行了充分的模拟。通过对均相两相湍流的直接数值模拟，揭示了颗粒与流体之间能量传递的基本结构。较少

Focusing on the clarification of the complex mechanism of transport processes in multiphase flows, a series of analytical and experimental investigations has been carried out concerning numerical prediction with a new type of turbulence models, i. e. , multiple scale for dispersed multiphase flows, the concerned development in instrumentation of high resolution sensing system by laser technique, and a signal processing system using on-line computing network.Basic development of instrumentation has been performed by a combined technique such as flow and temperature or concentration field measurements. A laser Doppler technique was extended to capture the particle shape using Shadow Imaging ; We called the technique as "SHADOW DOPPLER VELOCIMETRY". The Shadow Doppler method was applied to the flow filed in confined jet where non-spherical particle dispersed more than spherical particles due to their larger lift force caused by particle orientation.For the measurements of bubble flows, hi … More gh-speed digital camera was employed for the evaluation analysis with higher time resolution. Experiments have been conducted on bubble deformation and behavior in shear layer. The flow structure in the vicinity of the bubble boundary was analyzed by Digital particle image velocimetry supplemented the laser induced fluorescence particle and instantaneous shape by infrared Shadow Image Techniques. It was pointed out that the bubble-induced turbulence is primarily determined by bubble wobbling and stretch itself by the induced vorticity in the wake.The Streo-Paricle Image Velocimetry was developed to measure the third velocity component in the flow field, which was tested in a two-dimensional oblique jet evaluating the measurement error in the direction to the depth.From these experimental results, an adequate modeling has been done by combining the multiple time scaling for turbulent multiphase flows. Also, the direct numerical simulation on homogenous two-phase turbulent flow showed the fundamental structure of energy transfer between particle and fluid. Less