共查询到20条相似文献,搜索用时 0 毫秒
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为了分析复合材料螺旋桨的变形对桨后尾流场分布的影响,利用商业软件FLUENT和ANSYS有限元建立了一种流固耦合方法,基于此方法分析了桨叶变形对螺旋桨压力分布以及尾流场分布的影响。研究结果表明,变形后桨叶两侧压差增大;在螺旋桨尾流场中,变形对各速度分量周向分布的影响随半径增大而增大;在0.9R(R为螺旋桨半径)处,切向速度在变形后减小约30%,轴向诱导速度减小约20%,径向速度增值在0.1m/s内。变形后轴向速度低速度区域增大,径向速度正速度区域增大,叶根处切向速度增大,叶稍处切向速度减小。 相似文献
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Taek S. Jang Takeshi Kinoshita Hajime Yamaguchi 《Journal of Marine Science and Technology》2001,6(1):23-30
Based on Hilbert space theory, an infinite-dimensional optimization method to find the optimal pitch distribution of marine
propellers was developed. Thereby, the three-dimensional effect of induced velocity could effectively be controlled in an
optimal way; i.e., an investigation was carried out to learn whether the present method is applicable to the design of marine
propellers, especially pitch distributions, by maximizing the propeller efficiency functional. In addition, with the help
of Hilbert space theory, it was successfully shown that the optimization method developed has a unique mathematical solution.
In this work, only the pitch distribution was optimized, while other parameters such as the camber and thickness of the trial
propeller remained as in the original. With a numerical study, it is shown that the present optimization method gives an optimal
pitch distribution, the open-water characteristic curve being superior to the original curve.
Received: August 24, 2000 / Accepted: July 16, 2001 相似文献
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基于流固耦合的螺旋桨性能分析及参数优化 总被引:1,自引:0,他引:1
为了研究某型螺旋桨水动力及强度特性.首先建立螺旋桨实体模型,再在CFX中设置计算条件,运用CFD有限元方法计算与分析不同进速下螺旋桨的推力系数、转矩系数、敞水效率以及桨叶压力分布等水动力参数特性及其变化趋势;然后通过Workbench平台应用流固耦合方法,将CFX求解得到的螺旋桨表面压力载荷加载到螺旋桨结构强度分析模型上,对螺旋桨的强度进行计算.最后通过改变纵倾角和螺距对螺旋桨结构进行优化,并将仿真结果与原桨比较,结果表明适当增大纵倾角能增大螺旋桨强度,适当降低螺距能提高螺旋桨敞水效率、提高抗空泡性能并增大螺旋桨强度. 相似文献
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The aim of this work is to analyze the hydroacoustic behavior of a marine propeller through the acoustic analogy and to test the versatility and effectiveness of this approach in dealing with the many (and relatively unexplored) issues concerning the underwater noise and its numerical prediction. In particular, a propeller in a noncavitating open water condition is examined here by coupling a Reynolds averaged Navier–Stokes hydrodynamic solver to a hydroacoustic code implementing different resolution forms of the Ffowcs Williams–Hawkings (FWH) equation. The numerical results suggest that unlike the analogous aeronautical problem, where the role played by the nonlinear quadrupole sources is known to be relevant just at high transonic or supersonic regime, the pressure field underwater seems to be significantly affected by the flow nonlinearities, while the contribution from the linear terms (the thickness and loading noise components) is dominant only in a spatially very limited region. Then, contrary to popular belief and regardless of the low blade rotational speed, a reliable hydroacoustic analysis of a marine propeller cannot put aside the contribution of the nonlinear noise sources represented by the turbulence and vorticity three-dimensional fields and requires the computation of the FWH quadrupole source terms. 相似文献
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针对船舶电气系统常见的并联冗余设计,与传统的二状态可靠性分析方法不同,应用多状态可靠性理论,建立了船舶电气多状态并联冗余系统的可靠度数学模型,并进行了优化设计。实例给出了常见的三状态船舶电气并联冗余系统的可靠度表达式,证明由于短路失效的存在,即使采用更多的并联冗余支路组成的三状态船舶电气并联冗余系统,也不能有效地提高系统的可靠度。相反,过多并联支路反而会使并联冗余系统可靠度下降。与二状态不同,三状态船舶电气并联冗余系统常用的继电器辅助触点多支路冗余设计,最优冗余数仅为2。研究结果不仅适用船舶电气并联冗余系统,也适用于一般三状态并联冗余系统,具有普遍性。 相似文献
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通过对船舶电力推进系统螺旋桨负载的实时监测,提高对船舶电力推进系统的状态监测和故障分析判断能力,提出一种基于高阶统计量特征提取和串行D/A转换控制的船舶电力推进系统螺旋桨负载监测方法。采用振动传感器进行船舶电力推进系统螺旋桨的振动信号采集,振动信号能有效反映电力推进系统的负载特征,对采集振动信号进行时频分析和高阶统计量特征提取,以提取的特征量为测试集,进行负载监测的信号分析。在此基础上,基于ADSP21160处理器系统进行负载实时监测系统的硬件设计,通过D/A转换控制方法提高负载监测的实时性和准确性。仿真结果表明,该方法进行船舶电力推进系统的负载监测的实时分析能力较强,信号采集和输出的准确性较好。 相似文献