基于数值模拟的螺旋桨吸气及水动力性能研究

Propeller ventilation and hydrodynamic performance based on numerical simulation

[目的]为探究螺旋桨吸气带来的危害,在船舶设计阶段考虑防止螺旋桨产生吸气现象,开展CFD数值模拟研究。[方法]计算不同浸深比和进速系数下某螺旋桨模型的水动力性能,分析螺旋桨吸气现象的特点及其推力和扭矩变化,以及对比桨叶非定常载荷的变化。[结果]结果显示:浸深比h/D=1.0时,螺旋桨未产生吸气现象,其推力和扭矩无明显变化;浸深比0.6≤h/D<1.0时,螺旋桨受自由液面的影响,其推力和扭矩有一定的降低;浸深比h/D<0.6时,尤其在低进速系数时,螺旋桨产生了明显的吸气现象,其推力和扭矩显著下降。[结论]研究表明,当浸深比较小、进速系数较低时,螺旋桨容易出现吸气现象,并伴随着推力和扭矩的突变及桨叶受力脉动增大。

[Objectives]In order to explore the hazards of propeller ventilation and to prevent that during the ship design stage,a study of CFD numerical simulation is carried out.[Methods]The hydrodynamic performances of a propeller model with different immersion ratio and advance coefficients are calculated.The ventilation characteristics and the changes of propeller thrust and torque are analyzed.The changes of the nonconstant loads of a blade are compared.[Results]The results show that,for the immersion ratio h/D=1.0,the propeller has no ventilation,and its thrust and torque also have no significant change.For 0.6≤h/D<1.0,the propeller is affected by the free surface,and the thrust and torque have a certain reduction.For h/D<0.6,especially at lower advance coefficients,the propeller has a significant ventilation phenomenon and see a large decrease in the thrust and torque.[Conclusions]The study shows that,it's possible the ventilation happens in small immersion ratios and at lower advance coefficients,accompanied with the thrust and torque descending rapidly and pulsing steeply.