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

为了阐明多相流中输运过程的复杂机理，本文对一种新型湍流模型-湍流模型-进行了一系列数值预报的分析和实验研究。e.介绍了多相流测量的多尺度技术，激光技术高分辨率传感系统和在线计算网络信号处理系统的有关进展，以及流场、温度场或浓度场测量的组合技术的基本进展。本文将激光多普勒技术扩展到阴影成像技术，我们称之为“阴影多普勒成像”。本文采用阴影多普勒方法对受限射流中非球形颗粒的分散情况进行了研究，非球形颗粒的分散程度比球形颗粒的分散程度高，这是由于颗粒的取向性使颗粒受到较大的升力，而非球形颗粒的分散程度比球形颗粒的分散程度高。 关于我们 使用高速数码相机进行评价分析，具有较高的时间分辨率。对气泡在剪切层中的变形和行为进行了实验研究。采用数字粒子图像测速技术，辅以激光诱导荧光粒子和红外阴影成像技术，对气泡边界附近的流动结构进行了分析。指出气泡诱导湍流主要是由气泡在尾流中的诱导涡量引起的气泡摆动和拉伸所决定的，并发展了一种用于测量流场第三速度分量的Streo-Paricle Image Velocimetry，在二维斜射流中进行了实验，评价了沿深度方向的测量误差，实验结果表明，气泡诱导湍流的产生是由于气泡在尾流中的诱导涡量引起的。通过结合湍流多相流的多时间标度，已经完成了适当的建模。同时，对均质两相湍流流动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。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