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为准确预报螺旋桨的空泡性能和脉动压力性能,以某科考船螺旋桨为研究对象,分别在空泡水筒和减压水池进行空泡和脉动压力模型试验。对荷兰MARIN减压水池的试验方案进行论述,并对比分析空泡水筒和减压水池的试验结果。试验结果表明:目标船螺旋桨的空泡性能优秀,在11 kn航速工况下,螺旋桨无任何型式的空泡出现;在11 kn和15 kn航速工况下,螺旋桨的脉动压力非常小,该船的螺旋桨不会引起振动问题。螺旋桨应能满足挪威船级社DNV-GL Silent-R的低噪声要求。 相似文献
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文章分析了由螺旋桨空泡诱导的脉动压力对船体振动的影响及计算方法。为了进一步研究螺旋桨空泡对脉动压力的贡献量,以某船用螺旋桨为对象,分别进行了设计和压载工况下的空泡及无空化时的脉动压力试验。试验结果表明,在相应的测量点处,无空泡下时的对应阶次脉动压力值都低于发生空泡下的值,尽量减小或避免空泡的发生,将可有效减小螺旋桨诱导的脉动压力值,从而减缓船体的振动。 相似文献
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螺旋桨诱导船体表面脉动压力预报的试验研究 总被引:1,自引:0,他引:1
研究了螺旋桨诱导的船体表面脉动压力试验预报值随空气含量变化的规律及螺旋桨模型空泡形态随含气量变化的规律,并与实桨空泡对比分析;探索了脉动压力试验预报与实桨测量值最接近的空气含量控制准则;比较了螺旋桨模型在船模伴流场和修正后的伴流场中工作时,螺旋桨诱导的船体表面脉动压力预报值及螺旋桨模型空泡形态,与实船测量观察结果进行对比,并就伴流场修正对螺旋桨诱导的船体表面脉动压力试验预报的影响作了探讨;研究了螺旋桨诱导的船体表面脉动压力的预报值随桨模试验转速变化的规律。 相似文献
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参考国际拖曳水池会议(International Towing Tank Conference,ITTC)推荐规程,对螺旋桨空泡脉动压力试验的不确定度进行分析.根据脉动压力试验流程,确定试验过程中的误差源;根据不确定度传递函数,确定误差源对试验结果的影响.基于某油船的螺旋桨对3种工况进行10次重复性试验,并通过误差源分... 相似文献
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Investigation of cavitation inception characteristics of hydrofoil sections via a viscous approach 总被引:1,自引:0,他引:1
Unlike traditional approaches based on potential theory, this work investigated the cavitation inception characteristics of hydrofoil sections by solving Reynolds-averaged Navier–Stokes (RANS) equations. The viscous effects at high Reynolds numbers were taken into account through calculation of the eddy viscosity using a k- model. This viscous approach delivers the lift and drag forces in a more self-contained way, which cannot be obtained directly from the potential theory. A comparison with smooth surface measurements validates the proposed numerical method. Two approaches to include the roughness effects are also described. The predictions of cavitation bucket characteristics based on potential theory are more conservative than those reached by the proposed viscous computations. Hydrofoil sections with different camber ratios, foil thicknesses, and Reynolds numbers were studied numerically. A decrease in the Reynolds number tends to increase the cavitation-free region without changing the shape of the steep region. An increase in foil thickness gives a range increase in the angle of attack where no cavitation is expected. An increase in the camber ratio moves the cavitation-free location of the angle of attack, and slightly increases its range. 相似文献
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系列头体的空泡试验研究:初生空泡与发展空泡形态 总被引:11,自引:0,他引:11
学了掌握空泡形态及空泡水动力特征,为工程设计提供依据,本文对五个典型头体在不同空泡数,不同攻角条件下肩空泡形态特征进行了水洞试验研究,建立了平头系列轴对称体在不同攻角条件下的初生空泡数和发展空泡特征几何参数的工程计算公式。 相似文献
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翼剖面优化理论在螺旋桨设计和减荷切削中的应用 总被引:2,自引:1,他引:1
用Epller的叶剖面设计方法与螺旋浆升力面理论相结合的方法进行了水翼剖面的优化,并将其应用到螺旋桨减振降噪设计中获得了显著的效果,在螺旋桨减荷切削中用优化水翼剖面获得了出奇制胜的成功。 相似文献
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Hiroharu Kato Yuichi Oe Makoto Honoki Tetsuji Mochiki Taichi Fukazawa 《Journal of Marine Science and Technology》2006,11(2):131-138
This article presents the possibility of using a high-speed water jet for the dispersion of spilled oil at sea. Laboratory
experiments showed that a high-speed water jet is very effective in dispersing heavy oil. Two methods were examined and compared
using freshwater. The first method was to disperse an oil layer on the water surface using a cavitating jet ejected upward
at an angle of 45°. A target plate was placed at the interface of the water and oil layer to enhance the collapse of cavitating
bubbles. The second method was to eject a high-speed water jet vertically downward from the air. A guide plate with a guide
hole was placed under the oil layer with no target plate as such. The second method showed an improved dispersion ability
and thus its effectiveness was examined using an oil layer on seawater. The dispersion of oil was better in seawater than
in freshwater, probably because seawater contains natural surfactants. 相似文献
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A spherical and a nonspherical bubble dynamics models were developed to study cavitation inception, scaling, and dynamics in a vortex flow. The spherical model is a modified Rayleigh–Plesset model to account for bubble slip velocity and for nonuniform pressures around the bubble. The nonspherical model is embedded in an unsteady Reynolds-averaged Navier–Stokes code with appropriate free-surface boundary conditions and a moving chimera grid scheme around the bubble. The effect of nonspherical deformation and bubble/flow interaction on bubble dynamics is illustrated by comparing spherical and nonspherical models. It is shown that nonspherical deformations and bubble/flow interactions are important for an accurate prediction of cavitation inception. The surface-averaged pressure-modified Rayleigh–Plesset scheme is a significant improvement over the conventional spherical model, and is able to capture the volume changes of a bubble during its capture. It is also a fast scheme for studying scaling. In a preliminary study, the scaling effects on cavitation inception were examined using two different Reynolds numbers owing to two different chord lengths. The nuclei-size effect on the prediction of cavitation inception was also studied, and its important effects are highlighted. 相似文献
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The primary objective of this paper is to present cavitation tunnel tests performed on an optimised shape-adaptive composite hydrofoil and compare the results to other composite hydrofoils. The optimised composite hydrofoil was designed based on prior literature and was manufactured using an optimised ply orientation schedule and a pre-twist. In the same experiment schedule a composite hydrofoil that has a ply orientation that is opposite to the optimised hydrofoil was also tested. In addition to the cavitation tunnel experiments, the paper also presents results predicted from FEA and CFD simulations for the optimised hydrofoil and compares the results from numerical methods to experiments. The results show that the optimised hydrofoil has an improved L/D ratio and a delayed stall phenomenon compared to other hydrofoils. Furthermore, due to the pre-twisted optimised geometry, the hydrofoil does not suffer from loss of lift at low angles of attack. The experimental results demonstrated the importance of characterising the performance of flexible shape-adaptive hydrofoils based on the actual velocity of the flow in addition to the conventional characterisation based on Reynold's number. Additional numerical simulations were performed to investigate the hydrofoils observed load dependant deformation behaviour. These results clearly show that for the same Reynold's number, the hydrofoil can have an appreciably different response if the flow velocity is different. 相似文献
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高升阻比翼型优化及其节能轴支架设计 总被引:1,自引:1,他引:0
用Eppler的叶剖面设计方法与解N-S方程相结合的方法进行水翼剖面的优化,并给出了将其应用到螺旋桨节能轴支架设计中获得的显著节能效果的试验结果,空泡试验结果也证明了这种设计方法是成功的。节能轴支架的设计思想还被推广应用到单桨船上,开发出了扇形预旋导管。 相似文献