加速导管和减速导管的性能比较

为了研究不同形式导管桨的载荷特点,采用计算流体力学(CFD)技术分析了加速、减速导管的水动力特性及其对螺旋桨水动力性能的影响。计算域被分为包含螺旋桨的柱形域、包含导管的大域2个部分,并采用全结构化网格技术对其进行离散,以便优化网格质量和提高计算精度。用交界面技术保证不同计算域之间流体速度和压力等物理量的连续性。首先分析了JD7704+Ka4-5508导管桨的水动力性能,然后将计算值与试验值进行对比,验证了本文模型和网格技术的合理性。在此基础上,分析了不同翼形剖面拱度和攻角的加速、减速导管的水动力特性,及其对螺旋桨载荷的影响。研究表明,通过改变拱度和攻角2种方式所得到的加速和减速导管具有不同的水动力特性,能极大地优化螺旋桨的工况和载荷特点。

Performance comparison of accelerating duct and decelerating duct

In order to study the loading characteristics of different forms of ducted propellers, this paper analyzes the hydrodynamic performance of accelerating duct and decelerating duct and their influences on propellers by using computational fluid dynamics (CFD) method. The computation domain is divided into two parts:cylindrical domain containing the propeller and outer domain containing the duct. The computation domain is discretized by using fully structured gridding technique to optimize the quality of grids and improve the accuracy of calculation. The continuity of physical quantities such as fluid velocity and pressure between different domains is guaranteed by using the interface technique. This paper analyzes the hydrodynamic performance of JD7704+Ka4-5508 first, and the according results are compared with those by experiments to verify the rationality of the model and the grids technique. On this basis, this paper analyzes the hydrodynamic performance of accelerating duct and decelerating duct with varied cambers and angles of attack, and their influences on the loading state of propellers. The study shows that the accelerating duct and decelerating duct due to the variation of the cambers and angles of attack have different hydrodynamic performance, and they can optimize the propeller's operating conditions and loading characteristics greatly.