共查询到20条相似文献,搜索用时 9 毫秒
1.
2.
3.
本文根据我国一些建造数量较多或做过试航鉴定、吃水在1.2米以下的内河螺旋桨拖输,在线型设计方面加以总结。文中首先介绍了这些拖输的主要尺度、船型系数、性能指标、使用情况和存在问题。然后对浅水拖输的绕型设计进行分析研究。根据我国航道条件就现有浅水拖输艏艉线型形状进行了探讨,从阻力和推进观点出发对满载水线、横剖面形状、半进水角和各种墜洞以及它们对螺旋桨的影响等加以分析、比较。根据这些拖输在实际使用中的优缺点,提出比较适当的艏艉线型形状和墜洞类型。文中还探封了船体各种主要参数与线型设计的关系。讨论了各种主要尺度比、船型系数对阻力和推进的影响以及它们在浅水拖输设计中的常用范围。此外还讨论了与线型设计有关的稳性和操纵性问题。最后得出了简短的结论。 相似文献
4.
随着沉管和沉箱体积的大型化,浮运船舶尾流作用不容忽视,但目前国内相关研究较少。根据外文资料中计算螺旋桨射流作用的方法,分析船舶尾流作用范围及其流速变化,并计算其在沉管或沉箱上的尾流作用力,为沉箱、沉管浮运提供计算依据。 相似文献
5.
针对拖轮拖带沉管浮运航道宽度的既有设计方法具有局限性的问题,基于数值仿真进行了浮运航道宽度设计的研究.采用数值仿真模拟结果计算的深中通道沉管浮运航道宽度随拖轮就位时间增加而增加、随纠偏力增大而变小,较参考《海港总体设计规范》计算数值小约17 m.基于数值仿真的浮运航道宽度设计方法考虑了拖轮协同操纵因素,丰富了拖轮拖带沉... 相似文献
6.
Propeller blade width measurement has been extensively studied in the past using direct and indirect methods, and it plays a great role in determining the quality of the finished products. It has surveyed that previous techniques are usually time-consuming and erroneous due to a large number of points to be processed in blade width measurement. This paper proposes a new method of measuring blade width using two images acquired from different viewpoints of the same blade. And a new feature points matching approach for propeller blade image is proposed in stereo vision measurement. Based on these, pixel coordinates of contour points of the blade in two images are extracted and converted to real world coordinates by image algorithm and binocular stereo machine vision theory. Then, from the real world coordinates, the blade width at any position can be determined by simple geometrical method. 相似文献
7.
8.
一、概述以往一般均采用切割叶梢的方法来减轻螺旋桨负荷,然而切割叶梢后必将引起螺旋桨效率的降低,特别当切割叶梢较多时,效率降低更多。(这种方法只有在螺旋桨的设计负荷略 相似文献
9.
当航道上修建了桥梁并限制通航高度时,雷达桅就可能超高而阻碍拖轮通行。这时可以将雷达桅放倒,待通过桥梁后再将其恢复到正常工作状态。为此,需要设计一种使用简单快捷的可倒式雷达桅。 相似文献
10.
推拉杆式可调螺旋桨的轴系设计 总被引:1,自引:0,他引:1
推拉杆式调距桨由于其工作受力状况的特点,变距力对轴系的影响是不可忽视的。本文对考虑变距力后的轴系设计问题进行了探讨,并对“ZC”规范中的某些设计问题提出修改建议。 相似文献
11.
《船舶与海洋工程学报》2016,(2)
Fishing is a major local industry in Malaysia, particularly in rural areas. However, the rapidly increasing price of fuel is seriously affecting the industry's viability. At present, outboard petrol engines are the preferred choice for use in small-scale fishing boats because they deliver the advantages of high speed and low weight, they are easy to install, and they use minimal space. Petrol outboard engines are known to consume a greater amount of fuel than inboard diesel engines, but installing diesel engines with conventional submerged propellers in existing small-scale fishing boats is not economically viable because major hullform modifications and extra expenditure are required to achieve this. This study describes a proposal to enable reductions in fuel consumption by introducing the combined use of a diesel engine and Surface-Piercing Propeller(SPP). An analysis of fuel consumption reduction is presented, together with an economic feasibility study. Resulting data reveal that the use of the proposed modifications would save 23.31 liters of fuel per trip(40.75%) compared to outboard motors, equaling annual savings of RM 3962 per year. 相似文献
12.
13.
Hassan GHASSEMI 《船舶与海洋工程学报》2009,8(4):267-274
Demand for high-speed marine vehicles (HSMVs) is high among both commercial and naval users. It is the duty of the marine
vessel’s designer to provide a hull and propulsion system that diminishes drag, improves propulsive efficiency, increases
safety and improves maneuverability. From the propulsor side, surface piercing propellers (SPPs) should improve performance.
Unlike immersed propellers, behavior of the SPP is affected by depth of immersion, Weber number and shaft inclination angle.
This paper uses a practical numerical method to predict the hydrodynamic characteristics of an SPP. The critical advance velocity
ratio is derived using the Weber number and pitch ratio in the transition mode, then the potential based boundary element
method (BEM) is used on the engaged surfaces. Two models of three and six-bladed SPPs (SPP-1 and SPP-2) were selected and
some results are shown. 相似文献
14.
15.
船舶螺旋桨的射流冲刷作用是透空式码头结构的主要危害之一,现行的国内港口与航道工程规范并未涉及相关流速的计算和防护块石稳定性的设计.国内关于螺旋桨射流的防冲刷设计研究也主要集中在直立式码头结构,对透空式码头的防冲刷设计研究较少.通过分析国外规范和螺旋桨射流研究成果,并以某LNG码头防冲刷块石尺寸计算为例,总结归纳了船舶主... 相似文献
16.
17.
18.
19.
受长江航道的自然地形水深和南京长江大桥通航净空的限制,港口物流服务的腹地纵向延伸和广域化辐射受到较大阻碍,因此,在长江下游河段新建的港口宜尽量兼备承接上游来船转运出海的功能和由海轮转驳江轮的功能。现行规范对于挖入式港池宽度已有较为详细的规定,但对于船舶进出于两码头之间的挖入式港池口门宽度还没有明确的规定和要求,从航道角度出发,引入航行漂角和偏航角概念,着力于阐述船舶进出于两码头之间的挖入式港池口门宽度的计算确定方法。 相似文献