Development of Marine Propellers with Improved Cavitation Performance

利用二维翼型设计理论和升力面理论，研制了一种改善空化性能的新型船用螺旋桨。并对螺旋桨附面层和有限跨翼进行了计算和实验研究。得到以下结论：1。为了减小空腔体积，研制了压力均匀分布的螺旋桨。对新型和传统MAU型螺旋桨的实验表明，新型MAU型螺旋桨的空腔体积减小到MAU型的1/2 ~ 1/3，波动压力减小到MAU型的一半左右。由于具有上述压力特性的螺旋桨在叶段尾部的载荷分布变大，除非经过精心设计，否则推力会低于计算值。为了稳定板腔，针对M…More AU型螺旋桨产生云空化现象，研制了一种压力分布为三角形的螺旋桨。3 .新螺旋桨未见云穴现象，油漆试验未见MAU型螺旋桨出现的油漆剥落现象。提出了一种能够以较高精度实现目标压力分布的计算方案。提出了一种准三维近似的螺旋桨叶片边界层理论计算方法。虽然现阶段与实验的定量一致性还不够高，但由于计算结果能够反映实验中所观察到的螺旋桨边界层特性的差异，可以说这种方法是很有前途的。通过对各种有限跨度箔的理论计算，验证了等效二维箔概念的充分性。此外，提出了一些简单的方程，以获得修正的等效二维箔，其厚度比等效二维箔的厚度小，从而提高了计算精度。少

New marine propellers with improved cavitation performance were developed by using two-dimensional foil section design theory and lifting surface theory. Moreover, both calculation and experiment on propeller boundary layer and finite-span foil were performed as related research. The following conclusions were obtained.1. In order to diminish cavity volume, propellers with flat pressure distribution were developed. The experiment using both the new and conventional MAU type propellers showed that cavity volume of the new propellers reduced to 1/2-1/3 of that of the MAU type one, and the fluctuating pressure became about half of that due to the MAU type one.2. Since the load distribution of the propellers with the above-mentioned pressure characteristics becomes higher in the aft part of the blade section, the thrust becomes lower than the calculation unless carefully designed.3. In order to stabilize sheet cavity, a propeller with triangular pressure distribution was developed when a M … More AU type propeller generates cloud cavitation. The cloud cavitation was not observed on the new propeller, and the paint test showed that the paint peeling off which was observed in thr case of the MAU type propeller was not observed.4. A calculation scheme where target pressure distribution can be realized with relatively high accuracy was developed.5. A theoretical calculation method of boundary layers on propeller blade was developed, using quasi-three-dimensional approximation. This method can be said very promising sinve the calculated results could show the difference of the propeller boundary layer characteristics observed in the experiment although quantitative agreement with the experiment is not sufficiently high in the present stage.6. Adequacy of the concept of equivalent two-dimensional foil was verified from theoretical calculations on various finite-span foils. Moreover, some simple equations were proposed in order to obtain modified equivalent two-dimensional foil whose thickness is reduced than that of the equivalent two-dimensional one so as to make the calculation accuracy higher. Less