Data base accumulation for gas-liquid two-phase flow structures based on a construction of PIV parallel computation station

本研究构建了PIV(粒子图像测速系统)并行计算平台，并将其应用于多相流中的湍流结构分析。关于PIV并行计算站的建设：A-1我们开发了一种新的PIV和CFD混合系统，该混合系统包括求解Navier-Stokes方程的数值分析技术和PTV的速度梯度张量技术，证实了该混合系统可以计算Savonius型风力机周围的压力场。用三维PTV讨论了泡状流中的A-2气泡相互作用。本文提出了一种新的反分析方法，并将其应用于高含气率的气泡流，进而提出了一种计算液体…的新方法B.关于气液两相流动的湍流结构分析：B-1建立了高速高分辨率摄像机和剪应力传感器同步的新系统，并利用PIV测量结果阐明了壁面滑动泡状流的摩擦阻力修正机理。利用一种新的浅焦距PTV系统测量了近平壁气液两相流边界层中雷诺应力的分布，讨论了雷诺应力与边界层减阻之间的关系。为了研究螺旋管内泡状流和弹状流的湍流结构，研制了一套新的CT图像测量系统。结果发现并讨论了离心力对两相流和气泡分布产生二次流的影响，并发表在参考文献较少的学术期刊上的25篇论文

The present research has been carried out to construct a system of PIV (Particle Image Velocimetry) as a parallel computing station, and has been applied to analyze turbulent structures in multiphase flows. As a result, the following remarks were concluded ;A. Concerning construction of PIV parallel computing station :A-1 After we developed a new hybrid system of PIV and CFD which was a combined system consisting numerical analysis technique for solving Navier Stokes equation and VGT (Velocity Gradient Tensor technique for PTV, it was confirmed that the hybrid system could compute the pressure field around a Savonius type of wind turbine.A-2 Bubble-bubble interaction in bubbly flows were discussed with 3-D PTV. It was made clear that attractive forces were acted in the vertical direction and exclusive forces were acted in the horizontal direction.A-3 A new inverse analysis has been devised and applied to bubbly flows at high void fraction, and then a new technique for computing liquid … More phase flow field from PIV/PTV measurement using the inverse analysis has been developed.B. Concerning analysis of turbulent structure of gas-liquid two-phase flows :B-1 A new system for synchronizing a high speed high resolution vide camera and a shear stress sensor was constructed, and the friction drag modification mechanisms in wall sliding bubbly flows were elucidated with PIV measurement results.B-2 Effective viscosity, turbulent flow characteristics and additional viscosity were discussed in Taylor-Couette bubbly flows in a gap between coaxial double circular cylinders, and then the transition phenomenon from ring vortex to spiral vortex was visualized and discussed.B-3 Reynolds stress distribution in boundary layers of gas-liquid two-phase flows close to the flat wall was measured using a new shallow focal PTV system, and consequently the relation between Reynolds stress and friction drag reduction in the boundary layer of the two-phase flow was discussed.B-4 In order to elucidate the turbulent structures of bubbly flows and slug flows in a helical coil tube, a new CT image measurement system was developed. As a result, formation of secondary flows due to the centrifugal force effects on the two-phase flows and bubble distribution were newly found and discussed.All the above results were published as 25 papers in the academic journals described in the references Less