PPTC VP1304可调螺距螺旋桨敞水性能数值计算与尺度效应分析毕业论文

 2021-07-13 12:07

摘 要

调距桨是一种能在多航行工况下都可充分利用主机功率的推进器。它通过联合调节螺距和转速来适应船舶工况的变化,使船舶具备更好的机动性、操纵性和多工况适应能力,在船舶上具有广泛的应用。本文采用计算流体力学的手段来计算和研究PPTC VP 1304调距桨的敞水性能,并进行了尺度效应的相关分析。

论文的主要工作包括以下几个部分:

(1)将VP 1304调距桨的流场分为内域和外域两个部分,利用三维建模软件Solidworks对该螺旋桨的计算域进行了几何建模。

(2)运用ICEM程序进行螺旋桨流场计算域的网格划分。内域采用四面体非结构化网格划分,在桨叶表面尤其是导边、随边和叶稍区域进行了网格加密;外域采用六面体结构化网格进行划分。为了确保数值计算结果的网格无关性,生成了网格数量从小到大不等的一组网格。

(3)基于RANS方程和SST k-ω湍流模型,采用CFX程序对缩尺比分别为1、6和12的三个调距桨模型进行了数值计算,得到了该调距桨的速度矢量、压力分布等流场特征信息,以及推力系数、扭矩系数和敞水效率等外特性数据。

(4)比较了CFD数值计算结果和实验结果,验证了CFD预报调距桨敞水性能的有效性。通过对比缩尺模型和实尺模型的推力特性曲线,初步分析了调距桨的尺度效应。

通过本文的研究,可为调距桨的设计提供性能分析用的一种有效手段。

关键词:调距桨;CFD;敞水性能;尺度效应

Abstract

CPP (Controllable-Pitch Propeller) is a high-performance propulsion which can make full use of the main engine power in various conditions. It’s widely used for ship propelling, as the advantage of adjustable pitch and rotate speed along with the change of working condition. The open water performance of the PPTC VP 1304 propeller was obtained by CFD method, and compared with experimental data for scale effect analysis.

The main works in this paper are as follows:

(1) The computational domain was divided into two parts, the inner part and the outer, and the propeller model was set up using the 3D modeling software-Solidworks.

(2) The ICEM software was used to generate a three-dimensional mesh. Due to the complexity of the geometry, an unstructured mesh with tetrahedral elements was created around the propeller, and the mesh was refined. A structured mesh with hexahedral elements was used for outer field. In order to test and verify the grid independence of numerical simulation results, this paper generated a variety of mesh with different numbers.

(3) The RANS (Reynolds-averaged Navier-Stokes) equations along with the turbulence model were used in the simulation. To investigate the effect of scale model, the scale ratiowas set as 1, 6 and 12, and the pressure distribution of the controllable pitch propeller, the flow field characteristics, as well as the thrust coefficient, torque coefficient characteristic data and open water efficiency were obtained.

(4) The CFD numerical results were compared against experimental results which were available in the literature, the difference showed a good agreement. By comparing the thrust characteristic curves, the scale effect of CPP was preliminarily analyzed.

Through the study, this paper provided an effective method for performance analysis of CPP design.

Key words: Controllable-Pitch Propeller; CFD; Open water performance; Scale effect

目录

摘要 I

Abstract II

第一章 绪论 1

1.1 课题研究背景和意义 1

1.2 可调距桨研究现状 3

1.2.1 调距桨发展现况 3

1.2.2 螺旋桨水动力性能CFD研究现状 4

1.3 本文任务 6

第二章 计算流体力学基础 7

2.1 CFD简介 7

2.2 流体控制方程 7

2.3 湍流控制方程 8

2.4 边界条件 11

2.5 数值离散方法 12

2.6 本章小结 13

第三章 调距桨水动力性能CFD计算方法 14

3.1 几何模型 14

3.2 计算域构建 14

3.3 网格划分 16

3.4 边界条件设定 18

3.5 收敛判断 20

3.6 本章小结 20

第四章 调距桨数值分析结果 21

4.1 网格无关性验证 21

4.2 缩尺模型数值计算结果 21

4.3 实尺模型数值计算结果分析 24

4.4 叶片表面压力分析 26

4.5 叶片表面速度矢量分布 28

4.6 流线图 30

4.7 尺度效应分析 31

第五章 结论与展望 35

5.1 结论 35

5.2 展望 35

致谢 36

参考文献 37

第一章 绪论

1.1 课题研究背景和意义

可调距桨是一种通过设置与桨毂中的操纵机构,使桨叶能够转动而调节螺距的螺旋桨。与固定螺距螺旋桨相比,调距桨有以下优点[1]

(1)机动性好。调距桨能够在不改变螺旋桨和发动机转向的情况下,仅用改变桨叶螺距的方法得到从最大正值到最大负值的各种推力值,既可省去换向装备,又可缩短船舶换向航行的时间。

(2)经济性好。对于多工况船舶调距桨可以在各种工况航行时均充分利用主机功率,若同时改变主机转速和螺距比并使之配合适当,可以使船舶在单位时间内消耗的燃料最少。

(3)可以使船舶微速前进。对于某些低速性能要求较高的船舶(例如海洋调查船、布缆船、 猎扫雷舰等工程船和军用辅助船)要求船舶能够微速稳定航行,但装置定距桨的船最低 航速受到主机最低稳定转速的限制,而且要实现低速航行还要反复脱开和连接离合器,这不仅操作麻烦,而且有损于主机寿命。而调距桨只需改变螺距角即可在保持主机转速不变的条件下实现船舶的微速航行。

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