船用三叶涵道螺旋桨气动特性的数值模拟与分析

Numerical simulation and analysis of the aerodynamic characteristics of a marine three-blade ducted propeller

为研究某型在研应急救援气垫船上搭载的三叶涵道螺旋桨的气动特性,基于滑移网格方法建立涵道螺旋桨流场数值预报模型。设计3套不同疏密程度的非结构与结构混合网格方案进行不确定度分析,将NASA涵道螺旋桨的数值计算结果与实验数据进行比较,验证本文建立的数值模型具有较好的可靠性和准确性。基于建立的数值模型,分别计算了孤立螺旋桨和涵道螺旋桨在不同转速下的复杂流动。结果表明,相同转速下,涵道螺旋桨总推力系数较孤立螺旋桨增加10%,工作效率提高25%;涵道扩大了螺旋桨前部低压区的分布范围;涵道壁改变了螺旋桨桨尖流线特性,抑制了桨尖涡的形成,减少了能量损失;该型螺旋桨孤立状态下静推力为470 N,不能满足该型气垫船设计要求,加上涵道后其静推力为516 N,航行状态下推力为327 N,均能满足设计要求。

In order to study the aerodynamic characteristics of a marine three-blade ducted propeller carried on a hovercraft,established a numerical prediction model of the flow field of the ducted propeller based on the slip grid method.Three sets of unstructured and structural hybrid grid schemes with different grid density are designed for uncertainty analysis,and the numerical calculation results of NASA's ducted propeller are compared with the experimental data to verify that the model has good reliability and accuracy.Based on the established model,the complex flows of open propeller and ducted propeller at different rotating speeds are calculated respectively.The results show that at the same rotating speed,the total thrust coefficient of ducted propeller is 10% higher than open propeller,the working efficiency is 25% higher.The duct broadens the distribution range of low pressure areas before the propeller.The duct wall changes the streamline characteristics of the propeller tip,inhibits the formation of the tip vortex,and reduces the energy loss.The static thrust of this type of propeller in isolated state is 470 N,which cannot meet the design requirements of this type of air cushion vehicle.After adding the duct,static thrust is 516 N and the thrust is 327 N under sailing conditions,which can meet the design requirements.