无轴轮缘推进器水动力性能分析及桨叶强度校核

Hydrodynamic Performance Analysis and Blade Strength Verification of Shaftless Rim-driven Thruster

基于CFD数值计算,计算某无轴轮缘推进器轮缘内外表面、前后端面的摩擦扭矩值,并与经验公式值进行对比,结果表明,轮缘总摩擦扭矩与经验公式值的误差在1.3%之内。通过采用相同的方法计算JD75+Ka4-70导管桨的水动力性能,并与试验值进行对比,验证该方法的正确性。在此基础上,通过单向流固耦合方法对桨叶的结构强度进行计算分析,并对原型桨的桨叶厚度分布进行改变,分析桨叶厚度分布改变对无轴缘推进器水动力性能及桨叶强度的影响。结果表明:再设计桨的质量、推力、扭矩均有所下降,效率提高了2.1%。虽然桨叶最大变形量及最大等效应力均有所增加,但仍满足强度要求。在满足强度要求的条件下,可以通过有限元计算方法选择较为合适的桨叶厚度分布,提高无轴轮缘推进器的敞水效率。

Based on the CFD numerical calculation, the friction torque values of the inner, outer, front and end surfaces of the rim of shaftless rim-driven thruster(RDT) are calculated and compared with the empirical formula values. The results show that the error of the rim’s total friction torque of calculated value and the analytical value is within 1.3%. By using the same method to calculate the hydrodynamic performance of JD75+Ka4-70 ducted propeller, and comparing with the experimental results, the correctness of the method is verified. On the basis, the structure strength of the blade is calculated and analyzed through the unidirectional fluid solid coupling method. Then, the blade thickness distribution of the blade is changed, and the influence of the blade thickness distribution on the hydrodynamic performance and the blade strength of the propeller are analyzed. The results show that the quality, thrust and torque of the redesigned RDT have decreased, and the efficiency has increased by 2.1%. Although the maximum deformation and maximum equivalent stress of the blades increase, they still meet the strength requirements. Under the condition of satisfying the strength requirement, a more suitable blade thickness distribution can be chosen by the finite element method(FEM) to improve the open water efficiency of RDT.