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船用柴油机拉缸事故屡有发生。本文从柴油机的制造,螺旋桨与柴油机的匹配,燃油与气缸油的匹配,跑合时间和负荷分配各方面分析了产生拉缸的原因,并介绍了避免发生拉缸的经验。 相似文献
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柴油机冷却水温度是船舶重要状态参数之一,水温过高影响柴油机的散热效果,导致柴油机零部件热负荷升高、部件强度降低,同时使滑油温度升高、黏度降低,润滑效果恶化,加大运动部件的磨损。长时间在超过最高允许温度条件下运行,还会出现密封件老化、缸套漏水,甚至出现拉缸、轴瓦烧损等严重事故。 相似文献
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文章以一起真实的柴油机曲轴箱爆炸事故为例,从机舱管理的角度分析拉缸引起曲轴箱爆炸的具体原因,并提出预防拉缸机损的对策. 相似文献
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This paper presents the uncertainty modelling of experimental results for a physical model of a tanker moored to a terminal inside a port. The physical model was built for an oil terminal at the port of Leixões in Portugal. The model incorporates the new modified port layout, as well as a future 300 m extension of the port outer north breakwater to enhance operational conditions. The physical model tests were performed on a scale of 1:80 in the Portuguese Civil Engineering Laboratory (LNEC). A generic mooring system of four mooring lines and two fenders is simulated using a nonlinear spring system. Decay tests are carried out to evaluate the natural periods of the moored model. Then, tests are carried out for the moored model in waves. The major aim of the experimental study is to obtain novel results for the wave elevation and direction at various locations inside the port, the ship motions at six degrees of freedom, and loads on mooring lines and fenders including the modified port layout. As the physical model measurements are subjected to different types of uncertainties, a systematic uncertainty analysis is carried out here, following ITTC guidelines and recommendations, to quantify all possible sources of uncertainties. The results are discussed, and several conclusions are reached. Based on the experimental results, the presented physical model study may replicate the results for waves and motions with uncertainties less than 9% of the significant amplitudes. The assessment of the applied nonlinear spring model reveals load predictions on the moorings, with uncertainties less than 4% of the maximum mooring loads. 相似文献
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文章分析了传统故障诊断系统的特点,介绍了一种高分辨率谱估计算法-MUSIC算法,并针对该算法特点,提出了一种基于ARM微处理器的异步电动机嵌入式故障诊断系统,重点阐述了系统硬件电路和软件系统的设计,并进行了实验验证。结果表明系统具有硬件电路简单、可操作性较强、实时性可靠等优点。 相似文献
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Characteristics of a bubble jet near a vertical wall 总被引:1,自引:0,他引:1
A numerical model of a coupled bubble jet and wall was built on the assumption of potential flow and calculated by the boundary integral method. A three-dimensional computing program was then developed. Starting with the basic phenomenon of the interaction between a bubble and a wall, the dynamics of bubbles near rigid walls were studied systematically with the program. Calculated results agreed well with experimental results. The relationship between the Bjerknes effect of a wall and characteristic parameters was then studied and the calculated results of various cases were compared and discussed with the Blake criterion based on the Kelvin-impulse theory. Our analyses show that the angle of the jet's direction and the pressure on the rigid wall have a close relationship with collapse force and the bubble's characteristic parameters. From this, the application range of Blake criterion can be determined. This paper aims to provide a basis for future research on the dynamics of bubbles near a wall. 相似文献
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Eiji Shintaku Yukio Fujimoto Kunihiro Hamada Tetsuya Takeuchi 《Journal of Marine Science and Technology》2000,5(1):40-47
This paper describes a stress sensor using a piezoelectric element which was developed to monitor features of the stress
history of a structural member. The sensor is 90 mm long, 60 mm wide, and 25 mm thick. A stress-level meter can turn on and
off different colored light-emitting diodes (LED) according to the changes in a stress level. A stress-level cross counter
can display the number of cycles which exceeds a specified stress level during a monitoring period. The sensor is bonded onto
a structural member using an adhesive agent. In order to see the performance of the prototype sensor, experiments were carried
out using a fatigue-testing machine. The sensor was bonded onto a smooth specimen and multiple repeated stresses were applied
to that specimen. There were three main findings. (1) The sensor can operate under a stress range from −150 MPa to 150 MPa,
and a frequency from 0.05 Hz to 5 Hz. (2) The stress-level meter can turn the lights of the LED on and off accurately under
any stress amplitude and frequency. (3) When the stress frequency is 1 Hz or less, the stress-level cross counter can count
accurately the number of cycles which exceed the predetermined stress levels.
Received: February 25, 2000 / Accepted: April 11, 2000 相似文献
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通过对运输决策问题中某种基本情况的研究,建立运力有限情况下单个需求点单一物资运输的研究模型,给出求解模型的算法,通过一个算例进行了验证。与目前文献资料中类似研究模型相比较,在决策中考虑运达概率对运输决策的影响是本文模型的一大突出特点。 相似文献
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为优化某船用柴油机的燃烧室的"油-气-室"匹配,降低有害物排放,运用AVL Fire对原型燃烧室改用不同燃烧室进行额定工况模拟.结果表明,高低型双涡流室双缩口燃烧室能在上涡流室形成"飞轮效应",相对于原型燃烧室,不仅能增加功率,而且能降低Nox和SOOT的排放.对高低型双涡流室双缩口燃烧室设置不同的高低涡流室的半径比r/R和喷油夹角进行计算.结果表明:随着r/R从0.3增加到1.3,Nox和SOOT的排放量均先减少后增多;当r/R为0.7时,Nox和SOOT的排放量均最少.当喷油夹角为140°~165°时,随着喷油夹角的增大,Nox的排放量先减少后增加,随后再减少,最后又升高;SOOT排放量先减小后增大,随后再减小. 相似文献
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某船用大型可拆卸式滚动轴承设计 总被引:1,自引:0,他引:1
《中国修船》2019,(5):12-14
文章以船用滚动轴承为研究对象,针对该滚动轴承工作中存在的缺点和不足,设计了一种船用可拆卸式滚动轴承,说明了该滚动轴承的工作原理和主要零部件,并利用三维建模软件UG进行了该滚动轴承的零部件及装配体建模,最后进行了滚动轴承装配体的干涉检查,结果表明,所设计的船用大型可拆卸式滚动轴承运行良好。 相似文献