Mutual Interaction Between Turbulent/Laminar Separation Vortex and Cavitation Bubble

湍流/层流分离涡与空化气泡之间的相互作用

基本信息

批准号：
05650182
负责人：
SATO Keiichi
金额：
$ 1.47万
依托单位：
KANAZAWA INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05650182/
关键词：
Cavitation Separated Flow Vortex Interference Problem Bubbly Flow Critical Regime Turbulent Transition Bluff Body

项目摘要

For cavitation phenomena one of unsolved problems in the effect of flow characteristics due to occurrence of cavitation bubbles in the flow. In the present research the interference mechanism between cavitation bubbles and the flow characteristics was experimentally made clear from the viewpoints of flows about a bluff body which is one of typical vortex formation structures. In addition, the relation between hydrodynamic characteristics and impulsive force are discussed with the change of the flow field characteristics.In 1995, circular and triangular cylinders of various sizes were made as well as a circular cylinder with a splitter plate. The test cylinder was also made for examining the effect of the end plate. Bubble occurrence points, bubble types and cavitation shock pulses were measured under various air contents, flow velocities and test-section pressure. From the results, the flowabout a circular cylinder was qualitatively changed to a large extent due to the effect of the bubble occurrence with cavitation.In 1994, the flow visualization technique based on the dye injection into the flow was used in order to visualize the flow pattern, so that the flow characteristics of the double-peak cavitation process was caused by the transition from the laminar separation to the turbulent separation pattern. From the measurement of the base pressure of a circular cylinder, the transition of flow separation pattern due to cavitation creates the change of vortex strength and so repress the occurrence of cavitation itself. Next it was made clear that the splitter-plate effect weakens the interference of vortices and so reduces the occurrence of cavitation. Third, for the vortex cavitation the instantaneous measurement system between the bubble appearance and the impulsive force was successfully made to make clear the characteristics of these problems.

对于空化现象，由于流动中发生气泡气泡而导致流动特性的影响之一。在本研究中，从围绕一个典型的涡流形成结构之一的流动的角度来看，从空化气泡和流动特性之间的干扰机制清楚地表明了。另外，与流场特征的变化讨论了流体动力特征与冲动力之间的关系。在1995年，制作了各种尺寸的圆形和三角形圆柱，以及带有隔板板的圆形圆柱体。还制作了测试缸以检查端板的效果。在各种空气内容物，流速和测试部分压力下测量气泡发生点，气泡类型和气射击脉冲。从结果来看，由于气泡发生的气泡发生的影响。在1994年，基于染料注入到流动流中的流动可视化技术是为了可视化流动模式，因此，双峰式言论的流动过程是从层次分离引起的，因此使用了流动的流动模式，因此使用了流动可视化技术，从而在很大程度上改变了圆柱。从测量圆柱体的基本压力的测量，由于空化引起的流动分离模式的过渡会导致涡流强度的变化，从而抑制空化本身的发生。接下来，很明显，分离板效应会削弱涡流的干扰，从而减少了气蚀的发生。第三，对于涡流空化，气泡外观和冲动力之间的瞬时测量系统成功地表明了这些问题的特征。