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A Trial Manufacture of valves, which work safety in an extreme flow condition

试制极端流量条件下安全工作的阀门

基本信息

批准号：
04555041
负责人：
OBA Risaburo
金额：
$ 2.5万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04555041/
关键词：
Valve Butterfly-valve Cavitation Erosion Vortex Shear region Vibration Noise 上流キャビテータ

项目摘要

In order to make high reliability valves, which work safety in extreme flow conditions, we systematically observed the flow pattern and precisely measure the cavitation damage arisen around the butterfly-valve, the gate-slot and the hollow-jet-valve. In our study, we tool up the butterfly valve, because the butterfly valves are inexpensive, quite simple in construction, and can control the flow rate smoothly. We observed the flow pattern around a model of the butterfly-valve and measure the cavitation-induced-pressure-pulses by means of a pressure sensitive film and a hydrophone. The obtained results are summarized as follows :1. As a result of the observation of the flow pattern around the butterfly valves by means of a highspeed video camera, whose maximum framing rate is 40, 500 frames per second, the erosion on the surface of the downstream-pipe is closely related to the singular longitudinal vortex cavitation associated the high shear region between the orifice jet and the recirculating region. The vortex cavitation develops into the severely erosive cavitation in the recirculating region with combining the several vortex cavitations.2. The above-mentioned cavitation is weak as the projection is set on the orifice-side-surface of the butterfly valve, because the orifice jet becomes weak to be disturbed. We also make clear the cavitation-impulsive-pressures by means of the pressure sensitive film, and the cavitation noises by means of a hydrophone.3. In the case of the eccentric butterfly valve, in which it is very convenient to change the valve washer, there are two types on the setting to the flow direction, namely the convex part sets on the upstream or the downstream to the valve stem. It is shown that there is no difference on the flow rates between the two types of the setting.

为了制造出在极端流动条件下安全工作的高可靠性阀门，我们对蝶阀、门槽和中空射流阀门周围的流态进行了系统的观测，并对其空化损伤进行了精确的测量。在我们的研究中，我们制作了蝶阀，因为蝶阀价格便宜，结构简单，可以平稳地控制流量。我们观察了蝶阀模型周围的流态，并利用压敏膜和水听器测量了空化诱导的压力脉冲。1.利用最大取景速率为40,500帧/秒的高速摄像机对蝶阀周围的流态进行了观测，结果表明，下游管道表面的冲蚀与孔板射流与回流区之间的高剪切区的奇异纵向涡空化密切相关。结果表明：1.涡流空化在回流区发展为严重侵蚀空化，并与多个涡流空化相结合。当凸起设置在蝶阀的孔口侧面时，上述空化较弱，因为孔口射流变得不容易受到干扰。利用压敏胶片检测空化冲击压力，利用水听器检测空化噪声。对于偏心蝶阀，更换阀圈非常方便，在流向上有两种设置方式，即阀杆上游或下游的凸件设置。结果表明，两种装置在流量上没有差别。