Study on influence laws of high-skew propeller parameters on blade vibration modes

Abstract

ObjectiveThis study analyzes different high-skew propeller blade parameters to obtain the laws of their influence on blade vibration modes. MethodsA certain high-skew propeller is taken as the research object, a series of variable parameter schemes is designed and the finite element calculations for the vibration modes are conducted. The numerical method is validated effectively by adopting model tests. Through an analysis of the calculation results, the influence laws of the different design parameters on the blade natural frequency, attenuation coefficient and mode shapes are obtained. ResultsThe calculation results show that the blade natural frequency increases with its sectional thickness, area ratio and hub ratio, and decreases with its skew angle. Furthermore, the sectional thickness and skew have the greatest influence among the research parameters. The fluid-structure interaction effect has the greatest influence on the first order attenuation coefficient. The increase of the sectional thickness overall or at the outside radius is beneficial for reducing the first order attenuation coefficient. On the contrary, the increase of the area ratio, inward movement of skew balance point and large rake angle design is negative for first order attenuation coefficient reduction. The first order mode shape is almost the same for the series design scheme, which means that changes of the design parameters such as sectional thickness and skew angle mainly influence the blade's high order mode shapes. ConclusionThe results of this study can provide guidance and references for vibration mode optimization control in the design process of high-skew propellers.

Keywords

• high-skew propeller
• vibration mode
• fluid-structure interaction
• design parameter
• natural frequency