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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

这种支持使我们能够进行三种类型的实验和五种类型的理论分析，每一种都为理解旋转空化做出了宝贵的贡献。作为实验的第一步，建立了 LE-7 LOX 诱导轮和空化隧道的比例模型，并在广泛的操作条件下观察到包括旋转空化和空化浪涌在内的空化不稳定性。这导致了吸力性能图表中这些不稳定性的映射。此外，通过套管壁非稳态压力测量与为此目的新开发的数据采集系统相结合，可以将空腔从一个叶片到另一个叶片的传播可视化。观察二维瞬态叶尖泄漏流中的空化，作为叶尖泄漏空化的基础研究。研究发现，如果空穴增长效应适当地纳入计算中，则可以通过二维涡流计算来模拟空穴的增长。在此计算的基础上，我们计划建立一个三维叶尖泄漏空化模型，用于评估叶尖泄漏空化的非定常特性。为了评估叶片表面和叶尖泄漏空化的非定常特性，搭建了振荡箔试验装置。作为初步实验，固定箔的空化试验已经完成。结果发现，与传统的部分空化不稳定性一样，会出现更高频率的空化不稳定性。该装置将用于研究空化不稳定问题以及最初的目的。通过对旋转空化的非线性模拟发现，入口压力降低导致的空化柔量的增加是决定旋转空化振幅的一个因素。两个平行板之间或两个同心圆柱体之间的三维致动器盘分析表明，几何形状和腔体的 3D 效应对基本展向模式影响很小。有限节距空化级联分析的二维稳定性分析表明，在这种更详细的流动模型中不会出现旋转空化。因此，从各种打印角度来看，由于正质量流量增益因子，再次证实旋转空化基本上是一种二维局部流动不稳定。然而，详细的理论分析表明了尚未通过实验发现的其他类型的旋转空化的可能性。对这些模式的研究被作为未来的问题继续进行。较少的