共查询到18条相似文献,搜索用时 140 毫秒
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为验证扭曲舵的抗空化效果,在前期完成扭曲舵设计及实船换装工作的基础上,首次在国内开展了扭曲舵和普通舵的空化实船观测对比试验,对两种舵在设计航速和最大航速下固定舵角工况和直航自动舵工况的空泡进行了比较.结果表明:在相同航速工况下,扭曲舵的舵面空化起始舵角可提高10°左右,可以消除舰船常用航行状态下舵面的空化问题;在高航速大舵角工况时,扭曲舵的空化面积远小于常规舵;在扭曲舵优化的基础上,防腐蚀电极新型安装结构和舵下端导流罩可以有效解决防腐蚀电极和舵下端面的空化问题.通过扭曲舵空泡观测实船试验,证明了扭曲舵具有良好的抗空化性能,为抑制水面舰船舵空化剥蚀、降低船尾振动噪声提供了有效途径,具有优良的应用前景. 相似文献
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为深入研究空化后半悬挂舵非定常水动力性能的相关规律,采用结构化网格、DES湍流模型和VOF方法对某大型舰船的半悬挂舵空泡进行计算。探讨和分析舵空泡的周期性变化,同时简要分析半悬挂舵的间隙空化及端部空化产生的原因。基于空化和非空化2种状态对3个不同舵角下的舵空泡进行计算,总结了舵横向力、舵轴扭矩等非定常力的规律。结果表明:当空化区域较小时,空化对舵非定常力几乎没有影响,随着空化区域的增大,舵效显著降低;空化发生后,舵非定常力的脉动幅值将急剧增大,且空化区域越大,舵非定常力的脉动幅值越大。该研究结果可为评估空化状态下半悬挂舵的水动力性能及对舵进行优化设计提供技术支撑。 相似文献
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舵空化的精细流场及其非定常水动力性能数值计算 总被引:1,自引:0,他引:1
[目的]为深入研究舵空化时的精细流场及其非定常水动力性能的相关规律,[方法]针对某型船的桨、舵模型进行建模,采用结构化网格、SST k-ω湍流模型和流体体积(VOF)方法对舵空泡进行计算。针对舵空泡问题进行实船观测试验,将舵空泡的计算结果与实船舵空泡的观测结果进行对比,验证数值方法的可靠性。对舵空泡的周期性变化进行探讨和分析,并基于空化和非空化2种状态对3种舵角下的舵空泡进行计算。[结果]结果显示,当空化范围较小时,空化对舵力时均值的影响较小,随着空化范围的增加,空化对舵力时均值的影响明显变大,尤其是舵效显著降低;一旦发生空化,舵非定常力的脉动幅值将大幅增加,且空化范围越大,舵非定常力的脉动幅值越大。[结论]研究结果可为评估空化发生后舵的水动力性能及舵的优化设计提供技术支撑。 相似文献
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舵片是保证超空泡航行体运动稳定性和控制航行弹道的重要部分。文章基于均质平衡流模型和SST(Shear Stress Transport)湍流模型,计算了单独舵片的流体动力特性,并与试验数据进行了对比,结果符合较好,验证了计算模型的有效性。基于此方法,计算了单独舵片发生空化后在不同操舵状态下的非定常流体动力变化。结果表明,在攻角相同时,操舵状态下舵片的非定常升力系数和定常结果差别不大,而非定常阻力系数大于定常结果,并且操舵速度越快,阻力系数越大。另外计算了舵片发生空化后的流体动力系数,结果显示在攻角相同时,舵片的阻力系数和升力系数均小于其在全湿状态下的结果;在空化状态下,舵片升力系数的斜率小于全湿状态,并且舵片升力系数的斜率是变化的,存在某临界攻角,攻角大于此临界值时,升力系数的斜率减小,而此临界攻角恰好为舵片的吸力面刚刚出现空化时的攻角;操舵状态下舵片的阻力系数和升力系数的变化规律与定常结果一致,但是数值偏小。 相似文献
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文章介绍了换新舵系的安装工艺,着重论述了船舶舵系海损严重造成无基准的情况下,通过空心假轴进行舵系拉线,确保法兰座的定位,为整个舵系的安装提供了重要依据。 相似文献
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4250 TEU集装箱船舵空泡试验研究 总被引:1,自引:0,他引:1
大型集装箱船航速高,主机功率大,实船航运中半平衡舵上易产生由空泡引起的剥蚀危害。为改善这种状况,在船研所空泡水筒进行了4 250 TEU集装箱船舵空泡试验研究。观察操舵过程中舵空泡产生的情况,探讨降低舵剥蚀的方法,延长舵的有效使用年限。 相似文献
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This paper presents the numerical analysis of rudder cavitation in propeller slipstream and the development of a new rudder
system aimed for lift augmentation and cavitation suppression. The new rudder system is equipped with cam devices which effectively
close the gap between the horn/pintle and movable wing parts. A computational fluid dynamics code that solves the Reynolds-averaged
Navier–Stokes equations is used to analyze the flow field of various rudder systems in propeller slipstream. The body force
momentum source terms that mimic flow field behind a rotating propeller are added in the momentum equations to represent the
influence of the propeller and its slipstream. For detailed explication of the new rudder system’s lift augmentation and cavitation
suppression mechanism, three-dimensional flow analysis is carried out. Simulations clearly display the mechanism of the lift
augmentation and cavitation suppression. The computational results suggest that the Reynolds-averaged Navier–Stokes-based
computational fluid dynamics reproduces the flow field around a rudder in propeller slipstream and that the present concept
for a cavitation suppressing rudder system is highly feasible and warrant further study for inclusion of the interaction with
hull and mechanical design for manufacturing and operations. 相似文献
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Daewon Seo Seung-Hee Lee Sang-Hyun Kim Jungkeun Oh 《Journal of Marine Science and Technology》2012,17(1):18-29
Rudder cavitation causes serious damage to the rudder and affects the safety and cost-effectiveness of a ship. In recent applications,
a semicircular prismatic bar protruding beyond the concave surface of the horn facing the gap, located along the center-plane
of the rudder, has been used to lessen the gap flow between the horn and the movable portion of the rudder system. Previous
numerical studies with this single bar indicate that it can noticeably reduce rudder cavitation. In the present study, a pair
of bars for blocking the vertical gaps, which are attached symmetrically to the center-plane on opposite convex surfaces of
the movable portion, is suggested for circumventing the difficulties that arise in the practical application of single centre
bars. Placed near the outer edges of the gap, the bars are are easily accessible at the maximum rudder angle to allow simple
installation during routine ship maintenance. An additional blocking disk is inserted on top of the pintle block, blocking
the horizontal gaps. Three-dimensional computations are conducted with these combined devices and the results show that the
devices are remarkably efficacious in reducing rudder gap cavitation. 相似文献
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The flow around the gap of a semi-spade rudder was simulated as part of an effort to minimize gap cavitation. Simulations
were performed for various devices aimed at controlling the gap flow in two-dimensional and three-dimensional domains using
the Reynolds-averaged Navier–Stokes equations. A significant difference in the pressure field near the gap in two- and three-dimensional
computations was found. In particular, the pressure field of the gap, where the local flow is dominant, and that of the main
flow from the propeller were compared. Finally, a remedy for the gap cavitation that occurs between the horn and the rudder
was introduced. 相似文献
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船舶桨舵等装置均有水翼剖面组成,为了得到水动力性能更好的桨舵装置,需要对水翼进行优化设计。基于iSIGHT优化平台,采用粒子群优化算法,以保证水翼剖面升阻比和改善水翼表面压力分布为优化目标,进行多目标水翼优化。通过改变水翼剖面的拱度分布和厚度分布进行优化设计。优化后得到的最优剖面相对于原始剖面,明显增加了剖面的最小压力系数,并适当提高了升阻比,从而提高了水翼剖面的空泡性能和升力性能。因此,验证了利用多目标粒子群算法进行翼型优化设计的可行性。 相似文献
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在拖曳水池中进行了自航约束模舵力测量试验,对扭曲舵和普通舵的舵力进行了测量,比较分析了扭曲舵和普通舵的舵力特性。试验结果表明,在0°舵角时,扭曲舵上的受力状态得到明显改善,对舰船的直航性和舵机受力是有利的。在通过打舵使舰船发生回转时,扭曲舵不仅能使舵轴上的受力状态得到改善,而且能够提高舵的操纵力,改善舰船的回转性能。 相似文献