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Basic Investigation on Rotating Cavitation

旋转空化的基础研究

基本信息

批准号：
06452175
负责人：
TSUJIMOTO Yoshinobu
金额：
$ 4.86万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

项目摘要

This support enabled us to carry out three types of experiments and five types of theoretical analyzes, each of them resulting in valuable contributions for the understanding of rotating cavitations.As the first step of experiments, a scale model of LE-7 LOX inducer and a cavitation tunnel were built and cavitation instabilities including rotating cavitation and cavitation surge were observed in a wide rnage of operating conditions. This resulted in a map of those instabilities in the suction performance chart. In addition, the propagation of cavity from one blade to another could be visualized from a casing wall unsteady pressure measurement combined with a data acquisitions system newly developed for this purpose.The cavitation in a two dimensional transient tip leakage flow was observed as a basic study of tip leakage cavitation. It was found that the growth of cavitation can be simulated by a 2-D vortex calculation if the cavity growth effect is properly incorporated in the calcula … More tion. Based on this calculation, we are planning to build a 3-D tip leakage cavitation model which can be used to evaluate the unsteady characteristics of tip leakage cavitation.To evaluate the unsteady characteristies of blade surface and tip leakage cavities, and oscillating foil test device was built. As a preliminary experiment, a cavitation test with fixed foil has been finished. It was found that a higher frequency cavitation instability occurs as well as the conventional partial cavitation instability. This device will be used to study the cavitation instability problems as well as the original purpose.It was found by a non-linear simulation of rotating cavitation that the increase of cavitation compliance due to decrease of inlet pressure is a factor to the determine the amplitude of rotating cavitation. Three-dimensional actuator disk analyzes between two parallel plates or between two concentric circular cylinders showed that the 3-D effects of the geometry and cavity have little effects on fundamental span wise mode. A 2-D stability analysis of finite pitch cavitating cascade analysis showed that rotating cavitations disoccur in such a more detailed flow model.Thus it was reconfirmed that rotating cavitation is basically a 2-D local flow instability due to positive mass flow gain factor from various prints of view. However the detailed theoretical analyzes showed the possibilities of other types of rotating cavitations which have not been experimentally found. Studies of those modes were carried over as the future problems. Less

作为实验的第一步，我们建立了LE-7液氧诱导器的缩比模型和空蚀风洞，并在较宽的工况范围内观察到了包括旋转空蚀和空蚀喘振在内的空蚀不稳定性。这导致在吸入性能图中的这些不稳定性的映射。此外，还利用机匣壁面非定常压力测量技术和新开发的数据采集系统，对空泡从一个叶片到另一个叶片的传播过程进行了可视化研究，并对二维瞬态叶顶泄漏流中的空泡现象进行了观察，为叶顶泄漏空泡的研究奠定了基础。结果表明，如果在计算中适当地考虑空泡增长效应，空泡的增长可以用二维涡计算来模拟。 ...更多信息是的。在此基础上，建立了三维叶顶泄漏汽蚀模型，并建立了叶片表面和叶顶泄漏汽蚀的非定常特性试验装置，研究了叶片表面和叶顶泄漏汽蚀的非定常特性。作为初步的试验，进行了固定翼片的空化试验。结果发现，更高频率的空化不稳定性发生，以及传统的部分空化不稳定性。通过对旋转空化的非线性模拟发现，入口压力降低引起的空化柔度增加是决定旋转空化振幅的一个因素。对平行平板间和同心圆柱间作动盘的三维分析表明，几何形状和空腔的三维效应对基展向模态的影响很小。对有限螺距空化叶栅的二维稳定性分析表明，在这种更详细的流动模型中，旋转空化现象是不存在的，从而从不同的角度再次证实了旋转空化基本上是一种由于正的质量流量增益因子引起的二维局部流动不稳定性。然而，详细的理论分析表明，其他类型的旋转空泡的可能性，还没有实验发现，这些模式的研究被作为未来的问题进行。少