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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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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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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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传统船舵在船舶螺旋桨流程的影响下会产生空泡效应,造成船舵结构的损坏和转向功率的下降,造成船舶运营成本的提高。为了解决这一问题,行业内针对高效扭曲舵的研究成为一项热点。不同于传统舵,扭矩舵具有更好的水动力特性,能够克服船舶螺旋桨的尾流影响。本文的研究方向是对高效扭曲舵的水动力学特性进行理论分析和仿真,实现扭曲舵的最优参数设计,对于改善现有船舵的性能有一定的指导意义。 相似文献
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为了确定“雉鸡”级高速巡逻艇操纵性的各项参数,进行了两艘“雉鸡”级高速巡逻艇的操纵性实尺度试验。该系列巡逻艇实尺度的选择是基于能使同等动力条件下操纵性的各项参数达到最优的模拟研究所得的数据之上。试验包括回转试验、不同航速和舵角下的逼近试验、螺旋试验、Z形试验及制动试验,所有操纵性试验都是在良好的天气状况下进行的。主要叙述和分析了该级巡逻艇实尺度试验的结果。 相似文献
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泵喷推进器已经逐渐成为现代潜航器的首选,矢量推进器也在航空航天领域得到了广泛的应用。为了解决传统依赖船舵控制在低航速下控制效率低的问题以及提高潜航器回转性能,矢量推进器在潜航器上的应用已逐步成为国内外关注的热点。本文考虑大舵角(喷管偏角)下潜航器各参数非线性的影响,建立潜航器水平面操纵运动的非线性模型。通过仿真研究分析船-舵-推进器、船-矢量推进器和船-舵-矢量推进器三种不同的控制方法下潜航器在低航速、控制泵喷推进器转速、控制潜航器轴向航速三种不同条件下作水平面回转运动时的回转性能,结果表明矢量泵喷推进器可以有效改进潜航器的回转性能。 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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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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本文针对大型高速客货船舵系空泡剥蚀现象,提出了在舵系设计阶段就应考虑的关键点,以及舵的模型试验验证的相似律和试验方案;介绍了扭曲导缘和随缘舵的设计思路,也介绍了发生舵系空蚀后的补救措施;同时本文还回顾了舵的空化机理和抗空化舵叶剖面等方面的知识。 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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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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对复合材料舵和传统钢质舵的振动特性进行试验研究和对比分析.通过设计相关试验模型,对复合材料舵和钢质舵的前三阶固有振动模态及10 Hz~1 kHz频段内结构的动态响应进行测试,并对试验结果进行对比分析.研究结果表明:复合材料舵与钢质舵的模态振型基本相同,但复合材料舵所对应的固有频率高于钢质舵;同时,在白噪声激励载荷作用下,10 Hz~1 kHz频段内,复合材料舵整体加速度总级较钢质舵降低可达15 dB,且复合材料舵在局部壳板振动抑制方面明显优于钢质舵.本文研究将为复合材料舵的优化设计和工程应用提供参考和指导. 相似文献
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Takafumi Kawamura Kazuyuki Ouchi Takeo Nojiri 《Journal of Marine Science and Technology》2012,17(4):469-480
Computational fluid dynamics (CFD) analyses of propeller boss cap fins (PBCF) were carried out for two different propellers at model and full scale Reynolds numbers with two different inflow conditions. Computations corresponding to the reverse propeller open test (POT) experiment were confirmed to be in a good agreement with the measurement. The results of computations at different conditions have shown that increased Reynolds number and presence of hull wake both positively influence the effects of PBCF. Due to the combined effect of the Reynolds number and the wake, the gain in the propeller efficiency at the full scale condition was found to be significantly larger than that at the model test condition. The detailed investigation of the results suggested that the fin drag becomes smaller and the reduction of the boss drag becomes larger at the full scale condition. However, the predicted gain is still smaller than the values reported in the sea trial and logbook analysis. The remaining gap may be attributed to the difference in the estimated and actual wake distribution or to other factors such as interactions with hull and rudder, surface roughness, unsteadiness and hub vortex cavitation. 相似文献
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Vishwanath Nagarajan Dong-Hoon Kang Kazuhiko Hasegawa Kenjiro Nabeshima Toshihiko Arii 《Journal of Marine Science and Technology》2009,14(3):296-309
The influence of a rudder’s axial force on the prediction of full-scale powering performance of a ship is investigated in
this paper. Axial force characteristics of different rudder types were investigated by open water experiments. Viscous scale
effects on the rudder’s axial force were investigated by carrying out open water experiments with different sizes of rudder.
Experiments were carried out in the towing tank for a model ship fitted with different rudder systems to investigate the influence
of rudder’s axial force on full-scale propulsion performance prediction. Based on the experiment results, a new prediction
method is proposed for estimating full-scale power that considers scale effect on rudder’s axial force. Good performance of
the proposed prediction method is demonstrated by estimating the engine power of a ship installed with a special high lift
twin-rudder system from model experiments and comparing it with the values measured on the ship during full-scale experiments. 相似文献