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UNSTEADY HYDRODYNAMIC FORCES ON PARTIALLY SUBMERGED PROPELLERS

部分浸没的螺旋桨上的不稳定水动力

基本信息

批准号：
13650195
负责人：
FURUYA Okitsugu
金额：
$ 2.3万
依托单位：
KOGAKUIN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650195/
关键词：
PARTIALLY SUBMERGED PROPELLER VENTILATION HIGH SPEED SEA CRAFT HIGH PROPULSIVE FORCE WATER ENTRY VIBRATION 最適翼型非定常半没水型プロペラウォターエントリー翼の振動

项目摘要

Among all other candidate thrusters possibly used for high-speed sea crafts, a partially submerged ventilated propeller (PSVP) is said to have the highest propulsive efficiency theoretically. There exist two reasons: 1)a blade profile shape having a very high L/D such as 10〜15 was invented and proposed by Marshall Tulin in the early 50's, and 2)owing to the nature of PSVP, the propeller shaft and hub are above the water surface, and therefore are not subject to the hydrodynamic drag. However, the above nature also acts as a critical deficiency on the structure of PSVP ; at every rotation each blade enters into water surface and exits, causing a substantial mechanical vibration and thus damage to PSVP and its supporting system. It is for this reason that PSVPs are successfully used only up to 50 knots to date. The Tulin's blade section needs to have a sharp leading edge and thin blade thickness to achieve a high L/D value. It is naturally not a best, sturdy blade for use under this type of harsh conditions.During the research work conducted herein with use of two-dimensional blades entering into water tank, the following facts have been found. 1)The blade oscillatory characteristics matches with that of the waves of the separated free stream so that these waves are not of capillary or gravity type but those generated by the oscillation of the blade. 2)The Strouhal number based on the typical blade geometry, blade or wave frequency, and the blade entry velocity remains the same for all the cases tested. Although more elaborate experiments over many other parameters are needed, it seems that there exists the specific Strouhal number for this type of water entry blade. The later fact is important in designing a PSVP thrusting system for a sea craft ; it may be quite possible to avoid a severe vibration problem of the sea craft by considering the Strouhal number of the PSVP against the natural frequency of the propeller shaft, hub and/or the stern structure.

在所有其他可能用于高速海船的候选推进器中，部分潜水通风螺旋桨(PSVP)理论上据说具有最高的推进效率。这有两个原因：1)S在50年代初发明并提出了具有很高的L/D(10~15)的叶型，2)由于PSVP的性质，传动轴和轮毂都在水面上，因此不受水动力阻力。然而，上述性质也是PSVP结构的一个关键缺陷；在每次旋转时，每个叶片进入水面并离开水面，导致巨大的机械振动，从而损坏PSVP及其支撑系统。正是由于这个原因，到目前为止，PSVP只成功地使用了50节。土林的叶片截面需要具有锋利的前缘和较薄的叶片厚度，才能获得高的L/D值。这当然不是在这种恶劣条件下使用的最好的、坚固的叶片。在本文进行的使用二维叶片进入水箱的研究工作中，发现了以下事实。1)叶片的振动特性与分离的自由流的波动相匹配，因此这些波动不是毛细管型或重力型的，而是由叶片的振动产生的。2)基于典型叶片几何形状、叶片或波浪频率以及叶片入口速度的Strouhal数在所有试验情况下都保持不变。虽然还需要对许多其他参数进行更详细的实验，但对于这种类型的进水叶片，似乎存在特定的斯特劳哈尔数。后一个事实在设计船舶的PSVP推进系统时是很重要的；通过考虑PSVP的斯特劳哈尔数相对于传动轴、轮毂和/或船尾结构的固有频率，很可能避免船舶的严重振动问题。