排序方式: 共有68条查询结果,搜索用时 296 毫秒
11.
汽车传动轴跳动图解析计算法 总被引:1,自引:1,他引:1
本文旨用解析几何计算替代传统的几何画法求解汽车传动跳动图,使得解析计算求解法成为求解传动轴跳动图的有效方法;通过建立传动轴跳动的数学模型,运用计算机仿真技术在计算机屏幕上模拟传动轴跳动,使得传动轴跳动图更具有直观性。 相似文献
12.
13.
Genetic algorithms (GAs) can powerfully search for parameters in a large multidimensional design space. Thus, the principle
can be applied to preliminary series propeller design problems with multiple considerations. In the present study, B-series
propeller design was conducted using a GA for both hydrodynamic efficiency and vibration consideration. The objective function
was set by users who could freely weight the relative importance of efficiency and vibration. GAs were successfully shown
to be able to obtain an optimal set of parameters leading to efficient performance and low vibration. 相似文献
14.
对锰铜合金螺旋桨表现热涂涂层的性能进行了试验,并对采用热喷涂涂层防止螺旋桨腐蚀的可行性进行了研究。试验结果表明:采用高速氧燃料喷涂技术形成的Cu95超涂层人有优良的耐空蚀,耐海水腐蚀性能,可作为锰铜系合金螺旋桨表面的防腐涂层。 相似文献
15.
16.
Bu-Geun Paik Jin Kim Young-Ha Park Ki-Sup Kim 《Journal of Marine Science and Technology》2007,12(2):72-82
The vortex structure of the wake behind a marine propeller was investigated in terms of loading variation by using particle
image velocimetry. One hundred and fifty instantaneous velocity fields were ensemble averaged to study the spatial evolution
of the wake and the behavior of the tip vortices in the region ranging from the trailing edge to one propeller diameter downstream.
The trailing vorticity was found to be related to the radial velocity jump, and the viscous wake was affected by the boundary
layers developed on the blade surfaces. A vortex identification method using the swirling strength was employed to extract
the location of the tip vortex. The loading on the blade made a clear difference to the contraction angles. Slipstream contraction
occurred in the very near wake region, and unstable oscillation occurred because of reduced interaction between the tip vortex
and the wake sheet behind the maximum contraction point for each loading condition. The maximum tangential velocity around
the tip vortex center revealed the average radius of its core, which was used for calculating the vortex strength. Additionally,
variation of the average radius of tip vortices with the change of blade loading was related to vortex tube stretching in
the wake region. The nearly constant vortex strength continued up to one diameter downstream for light loading and design
loading conditions. 相似文献
17.
18.
此研究从N-S基本方程出发,采用亚格子尺度模型,运用大涡模拟方法,通过数值计算研究了船舶螺旋桨机翼型桨叶在低马赫数下的粘性绕流情况,其中包括创建模型、网格划分等,获得了速度场、压力场和涡量场等图像,对减小船舶阻力、降低振动噪声和提高船舶螺旋桨的设计水平具有十分积极的现实意义。 相似文献
19.
20.
依靠图谱和经验进行船用螺旋桨的设计已经不能适应时代的要求,运用数字化手段进行设计与制造已经成为当前的主要发展趋势。本研究创新了一种船用螺旋桨边界曲线改型方法,改型过程中通过移动导边侧约束面和随边约束面的位置来控制边界曲线的形状,从而实现螺旋桨的改型设计。通过fluent软件模拟,发现随边侧约束面沿拉伸方向的移动可以有效提高螺旋桨推进效率,最高可以达到53.2%,而导边侧约束面的移动在一个相对较小的范围内对螺旋桨效率的提高有明显的作用。因此,这种拉伸式的逆向改型方法对设计具有高效率的螺旋桨具有重要的应用价值。 相似文献