船体伴流对直翼推进器水动力性能的影响

目的]直翼推进器是一种特种推进器,其借助从船舶底部伸出并围绕垂直轴往复式摆动的桨叶产生精准且无级可调的推力,有必要研究敞水和伴流条件下直翼推进器的水动力性能。方法]首先,通过分析直翼推进器的工作原理,推导出叶片的多重运动规律公式;然后,基于RANS方程和k-ε湍流模型,采用滑移网格技术计算直翼推进器的敞水性能;最后,与试验值进行比较,验证直翼推进器水动力性能预报方法的准确性,并在考虑船体伴流影响的情况下,研究直翼推进器的非定常水动力性能。结果]由整桨瞬时载荷和单桨叶瞬时载荷变化规律的分析,显示叶片瞬时载荷存在明显的叶频特征,且随着进速系数的减小,桨叶主推力和转矩的波动幅值增大;船体伴流对直翼推进器主推力和转矩的影响较小,但侧向力变化显著。结论]研究结果对于分析直翼推进器的桨叶强度以及叶型优化具有借鉴意义。

Influence of ship wake on hydrodynamic performance of cycloidal propeller

Objective]The cycloidal propeller is a special propeller which generates thrust by means of profiled blades that protrude from the hull of the vessel and rotate around a vertical axis,allowing precise and stepless thrust generation.It is necessary to study the hydrodynamic performance of cycloidal propeller in open-water and hull wake conditions.Methods]By analyzing the operating principle of the cycloidal propeller,a formula for the multiple motion laws of the blades is derived.The open-water performance of the cycloidal propeller is then calculated using the RANS equations and turbulence model based on a sliding mesh.Comparison with the experimental data verifies the accuracy of the hydrodynamic performance prediction method of cycloidal propeller.The propellor’s unsteady hydrodynamic performance in a ship’s hull wake is also investigated.Results]The results show that the force on the cycloidal propeller and singular blade has blade frequency characteristics;the fluctuation amplitudes of the thrust and torque increase with the increase of the advanced coefficient;and the lateral force is significantly affected by the hull wake,while the thrust and torque are slightly affected.Conclusions]The results of this study have important reference value for research on blade strength evaluation and blade design optimization.