In view of the supercavitation effect, a novel device named the rotational supercavitating evaporator (RSCE) has been designed for the desalination. In order to improve the blade shape of the rotational cavitator in the RSCE for the performance optimization, the blade shapes of different sizes are designed by utilizing the improved calculation method for the blade shape and the validated empirical formulae based on previous two-dimensional numerical simulations, from which the optimized blade shape with the wedge angle of 45° and the design speed of 5 000 r/min is selected. The estimation method for the desalination performance parameters is developed to validate the feasibility of the utilization of the results obtained by the two-dimensional numerical simulations in the design of the three-dimensional blade shape. Three-dimensional numerical simulations are then conducted for the supercavitating flows around the rotational cavitator with the optimized blade shape at different rotational speeds to obtain the morphological characteristics of the rotational natural supercavitation. The results show that the profile of the supercavity tail is concaved toward the inside of the supercavity due to the re-entrant jet. The empirical formulae for estimating the supercavity size with consideration of the rotation are obtained by fitting the data, with the exponents different from those obtained by the previous two-dimensional numerical simulations. The influences of the rotation on the morphological characteristics are analyzed from the perspectives of the tip and hub vortices and the interaction between the supercavity tail and the blade. Further numerical simulation of the supercavitating flow around the rotational cavitator made up by the blades with exit edge of uniform thickness illustrate that the morphological characteristics are also affected by the blade shape.

中文翻译：

---

优化叶片形状的旋转超空化蒸发器对旋转自然超空化形态特征的数值研究

考虑到超空化作用，已经设计了一种新型的装置，称为旋转超空化蒸发器（RSCE），用于脱盐。为了改进RSCE中旋转空化器的叶片形状以优化性能，利用改进的叶片形状计算方法和基于先前二维数值模拟的经过验证的经验公式，设计了不同尺寸的叶片形状。 ，从中选择楔形角为45°且设计速度为5 000 r / min的优化叶片形状。开发了淡化性能参数的估计方法，以验证利用二维数值模拟获得的结果在三维叶片形状设计中的可行性。然后，以最优的叶片形状在不同的转速下，对围绕空化器的超空化流进行三维数值模拟，以获得旋转自然超空化的形态特征。结果表明，由于重入射流，超腔尾部的轮廓向超腔内部凹陷。通过拟合数据，获得了考虑到旋转量来估算超腔尺寸的经验公式，其指数不同于先前的二维数值模拟获得的指数。从叶尖和轮毂涡以及超腔尾部与叶片之间的相互作用的角度分析了旋转对形态特征的影响。