Development of Marine Propellers with Improved Cavitation Performance

应用二维翼型截面设计理论和升力面理论，研制出空泡性能得到改善的新型船用螺旋桨。此外，还对螺旋桨边界层和有限跨度翼片进行了计算和实验研究。得出了以下结论：1.为了减小空腔体积，开发了压力分布平坦的螺旋桨。用新型和常规MAU型螺旋桨进行的试验表明，新型螺旋桨的空腔体积减小到MAU型螺旋桨的1/2~1/3，脉动压力约为MAU型螺旋桨的一半。由于具有上述压力特性的螺旋桨在叶片截面后部的载荷分布较大，除非精心设计，否则推力将低于计算值。为了稳定片状空腔，研制了一种三角形压力分布的螺旋桨，当M-…更多的AU型螺旋桨产生云空泡。在新螺旋桨上没有观察到云空泡，油漆试验表明没有观察到在MAU型螺旋桨上观察到的油漆剥落。提出了一种能以较高精度实现目标压力分布的计算方案。提出了一种基于准三维近似的螺旋桨叶片边界层理论计算方法。这种方法可以说是非常有前途的正弦，计算结果可以显示出实验中观察到的螺旋桨边界层特性的差异，尽管现阶段与实验的定量一致性还不够高。通过对各种有限跨度翼片的理论计算，验证了等效二维翼片概念的充分性。此外，还提出了一些简单的公式，以求得到修正的等效二维箔，其厚度比等效二维箔的厚度要小，从而使计算精度更高。较少

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