船舶螺旋桨进流补偿导管

螺旋桨的进流品质对螺旋桨效率与船舶推进性能有很大的影响。螺旋桨的进流补偿导管是以改善螺旋桨进流为主,从而改进船舶的推进性能,它本身亦产生附加推力,有节能效果,视船型和方形系数不同达5～11％。本文介绍江海直达1000吨沿海货船“闽海102”采用补偿导管的模型试验和实船试航结果。     

带前置定子导管桨非定常力特性计算分析

本文采用数值求解RANS方程的方法对带前置定子导管桨进行了数值模拟,计算了非均匀来流下带前置定子导管桨的非定常力,研究了来流周期数和转定子叶数对带前置定子导管桨转子非定常力的影响规律.结果表明:转子的非定常力主要由转子的进流决定;转子的进流同时受到非均匀来流和定子叶片数的影响;高周期数的非均匀来流诱导的非定常侧向力幅度要小于相同脉动幅度的低周期数的非均匀来流诱导的非定常侧向力幅度;转定子叶数要适配以减小转子的非定常力.本文的研究结果可为低激振导管桨设计及其非定常力特性分析提供基础.     

补偿导管推力的试验研究

补偿导管于１９８４年３月１４日首次装船至今，已有数百艘实船采用了该节能装置投入营运，实船使用证实了船模试验所的节能效果４－１０％，本文介绍在一般５０００号多用途货船模型阻力自航试验过程中进行补偿导管推力的试验研究。该船模所安装的补偿导管上测得正和，表明其推力大于自身的阻力，其量级很小，不是补偿导管产生节能效果的主要原因。     

抑制桨-船连体涡空泡的措施及讨论

文章介绍在中国船舶科学研究中心大型循环水槽的一集装箱船模型空泡试验中观测到了连体涡空泡(PHVC)。为此,结合三个新设计桨方案和附体(涡流发生器、预旋导轮和伴流补偿导管)开发了四套用于抑制连体涡空泡的措施。其中,三套达到了工程应用的要求。基于这些工作以及在实验室积累的模型试验数据的基础上,提出了水动力相互作用强度因子I_H,并建议I_H≤3.2作为连体涡空泡评判的保守准则。当船舶螺旋桨的进流足够好或者控制得足够好时,可以在I_H3.2时不发生连体涡空泡。     

矢量泵喷推进器水动力性能

传统水下航行器采用鳍舵装置控制航向和航速，舵的存在降低了推进器的进流品质，增强了推进器直发声，引起艇体结构振动。为解决这一问题，设计一种全新的泵喷推进方式，在泵喷推进器的导管尾缘处加装一段能够调整和控制方向的尾喷管。基于STAR-CCM+软件进行数值计算，结果显示：此种矢量泵喷推进器可以产生较大的横向操纵力，可以实现舵的操纵效果。     

喷水推进器进水流道进流面形状研究

采用动量法预报喷水推进器的推力和效率时,进水流道进流面的动量和能量的精确求取是影响预报精度的关键因素之一.当喷水推进器的流量以及船体边界层速度分布已知时,还需确定进流面的形状才能求取进口的动量和能量.有关进流面形状及其对推进性能的影响程度,目前还存在争论.本文采用CFD方法对进水流道的流场进行了数值模拟,通过求解一个用户自定义标量方程获取了不同进口速度比(IVR)条件下的流管及进流面形状.计算结果表明:①对于常见的平进口式矩形进水口,流管和进流面宽度约为进水流道宽度的2倍,且随进速比IVR的变化不明显;②随着IVR减小,进流面深度逐渐减小,进流面形状从饱满的半椭圆形逐渐变平坦,IVR很小时(IVR<0.3)进流面在中心线附近有所内陷;③同一工况下,进流面形状在进水口之前船体首尾方向不同的位置处基本不变.     

某伴流补偿导管对螺旋桨空泡及 空泡剥蚀性能影响研究

文章介绍了中国船舶科学研究中心大型循环水槽中开展的某散货船有、无伴流补偿导管下螺旋桨空泡、空泡剥蚀性能对比试验研究,并深入分析某伴流补偿导管对空泡形态、空泡剥蚀性能影响及导管设计过程中需注意的问题。试验结果表明:前置伴流补偿导管会增加螺旋桨表面空泡面积及空泡诱导的船体脉动压力一阶叶频分量,且不合适的伴流补偿导管安装方式会增加桨叶空泡剥蚀风险。     

船体节能措施的新进展

联邦德国研究技术部(BMFT)于1978年制订了一项为期5年的船舶技术科研发展规划。在此时期,一批船舶科研项目取得了重大突破。一些多年停留在理论研究的项目获得了实际应用。这些成果推动了联邦德国船舶技术的发展,在国际船舶市场受到了普遍的重视。本文仅就格林姆导轮、整流鳍和进流均衡导管作一介绍。     

伴流补偿导管,舵球与节能研究

本文着重介绍了作者近几年来在水动力附加节能装置方面的研究成果，特别对伴流补偿导管及舵球的节能技术和机理作了进一步的探讨，提出伴流补偿导管的纵向安装位置有时是能否取得节能效果的关键参数、指出了舵球节能效果最佳垂出安装位置并不一定在桨轴中心线上的观点，这对进一步开展水动力附加节能装置的研究有一定的参考意义。     

矢量泵喷推进器水动力性能

传统水下航行器采用鳍舵装置控制航向和航速,舵的存在会降低推进器的进流品质,增强推进器的直发声,引起艇体产生结构振动。为解决该问题,设计一种全新的泵喷推进方式,在泵喷推进器的导管尾缘加装一段能调整和控制方向的尾喷管。基于STAR-CCM+软件进行数值计算,结果表明:该矢量泵喷推进器可产生较大的横向操纵力,可实现舵的操纵效果。     

Estimation and prediction of effective inflow velocity to propeller in waves

A free running test using a container ship model clarified properties of effective inflow velocity to propellers in waves. The analysis assumes that thrust and torque vary keeping their relation to the effective inflow velocity as represented by open-water characteristics of a propeller in a steady calm water condition. Measurement in regular waves confirmed the variation of average values of the effective wake coefficient and ship speed depending on wavelength and wave encounter angle. Comparison with the longitudinal flow velocity measured at the sides of the propeller using an onboard vane-wheel current meters confirmed that one can estimate the effective inflow velocity based on thrust or torque data. Theoretical estimates in regular waves based on a strip method are provided and compared with the experimental data. A prediction model of the future inflow velocity is proposed to cope with a time delay of a propeller pitch controller for higher propeller efficiency in waves.     

Numerical calculations of propeller shaft loads on azimuth propulsors in oblique inflow

This paper evaluates various computational methods used to compute propeller performance, hydrodynamic side force and bending moment applied to an azimuth propulsor propeller shaft in oblique inflow. The two non-viscous models used are the BEM method and the blade element momentum theory (BEMT). RANS calculations are used to compute the loads on the propeller and the nominal wake velocity from the thruster body to be used in the BEMT model. The effect of the ship hull is also considered in the calculation by implementing the measured nominal wake of a ship hull at different propeller azimuthal positions. All the models are compared and validated against the experimental results, and the discussions are presented.     

考虑桨前预旋流的自航试验分析及实船预报

本文根据有关文献提出的预旋流的概念,给出了包括横向非对称船型及多桨船型在内的多种船型的桨前流动的预旋转速(或称切向伴流相当转速)的精确计算方法,以及船模预旋转速实船预旋转速间的关系和考虑预旋流动的实船预报,文中还讨论了十八届国际水池会议给出的计算双桨船模型桨前流动的预旋转速的近似性,最后以程序计算的形式,把预旋流概念同时引入自航试验分析和实船预报中。     

Statistical consideration of propeller load fluctuation at racing condition in irregular waves

Propeller load fluctuation in rough sea conditions is caused by two components: one is the fluctuating inflow velocity and the other is the emergence of the propeller disk from the water. Such disturbances cause large fluctuations in engine power and revolutions, and can lead to the failure of the propulsion plant, which is unacceptable in extreme seas. However, due to strong nonlinearity in the effect of propeller emergence and nonlinear interactions with the inflow velocity in the propeller torque fluctuation, the procedure for obtaining the statistical properties of the propeller torque in extreme sea conditions is not clear. If the statistical properties of propeller torque fluctuation—such as the variance and the probability density function—are known, the corresponding statistics of the response of the engine can be obtained, allowing the safe operation of ship propulsion plants in extreme irregular seas to be assessed.     

Prediction of ship steering capabilities with a fully nonlinear ship motion model. Part 1: Maneuvering in calm water

This paper introduces a new method for the prediction of ship maneuvering capabilities. The new method is added to a nonlinear six-degrees-of-freedom ship motion model named the digital, self-consistent ship experimental laboratory (DiSSEL). Based on the first principles of physics, when the ship is steered, the additional surge and sway forces and the yaw moment from the deflected rudder are computed. The rudder forces and moments are computed using rudder parameters such as the rudder area and the local flow velocity at the rudder, which includes contributions from the ship velocity and the propeller slipstream. The rudder forces and moments are added to the forces and moments on the hull, which are used to predict the motion of the ship in DiSSEL. The resulting motions of the ship influence the inflow into the rudder and thereby influence the force and moment on the rudder at each time step. The roll moment and resulting heel angle on the ship as it maneuvers are also predicted. Calm water turning circle predictions are presented and correlated with model test data for NSWCCD model 5514, a pre-contract DDG-51 hull form. Good correlations are shown for both the turning circle track and the heel angle of the model during the turn. The prediction for a ship maneuvering in incident waves will be presented in Part 2. DiSSEL can be applied for any arbitrary hull geometry. No empirical parameterization is used, except for the influence of the propeller slipstream on the rudder, which is included using a flow acceleration factor.     

螺旋桨噪声的无量纲化研究

实船和船模的螺旋桨噪声存在一定的相似性,通过无量纲分析船模螺旋桨噪声可以预报实船的螺旋桨噪声。本文利用无量纲分析方法,得到影响螺旋桨噪声的一些因素,如雷诺数、桨直径、桨转速、频率、空泡数等。在此基础上对这些因素进行分析,并提出修正方法。     

船桨干扰定常空化性能数值模拟

文章采用CFD技术计算了船桨干扰定常空化性能。首先计算了不同空化数下的NACA66(MOD)水翼和DTRC4381螺旋桨的定常空化性能,同时预报了KCS船的伴流场、阻力性能和船体表面压力分布。为了验证计算船后螺旋桨空化流的可行性,文中对KCS船和KP505螺旋桨进行了整体考虑,并计算了不同空化数下的船后螺旋桨的空化覆盖面积。计算表明,文中采用的计算方法合理,计算结果与试验结果吻合。     

船舶回转过程内、外桨负荷的仿真分析

船舶在回转过程中,一般内桨的负荷要大于外桨的负荷.但在某新研制船舶的回转试验中,观察到外桨负荷高于内桨负荷这一看似有悖常理的现象.为了解释这个现象,利用船舶推进系统的数学模型和三自由度平面运动数学模型(MMG模型),分别对定距桨和调距桨推进船舶的典型回转工况进行了仿真分析.研究结果表明:在负荷控制功能起作用的情况下,船舶回转时通过减小柴油机设定转速或减小调距桨的螺距,内桨的负荷比外桨小是完全可能的.在相同回转工况下,负荷限制线的设置和负荷控制规律对船舶内、外桨的负荷有很大的影响.控制系统的负荷控制功能是改变船舶回转工况内、外桨负荷的一个重要因素.