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平光明 《山东海洋学院学报》1984,14(1):19-19
内河拖轮和拖网渔轮等各类船舶上采用了螺旋浆导管以后，能显著地提高推进效率，尤其是对重负荷螺旋浆，效果更为明显。但是却存在一个严重问题，即导管内壁侵蚀严重，妨碍了船舶经济效益和运营效率的提高， 相似文献
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平光明 《中国海洋大学学报(自然科学版)》1984,(1)
内河拖轮和拖网渔轮等各类船舶上采用了螺旋浆导管以后,能显著地提高推进效率,尤其是对重负荷螺旋浆,效果更为明显。但是却存在一个严重问题,即导管内壁侵蚀严重,妨碍了船舶经济效益和运营效率的提高, 山东海洋学院承担了原国家水产总局下达的《螺旋桨防蚀研究》的任务,在调研和 相似文献
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研究设计了一艘适用于浅海油田的高速交通艇，该艇采用深V线型和在侧斜螺旋浆，设有主动式减摇鳍。实船航行表明该艇具有优良的耐波性。 相似文献
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超导潜艇超导潜艇又称磁流体潜艇，是以超导技术为基础的电池推进潜艇，采用一种全新的、没有螺旋浆和减速箱等传动机械的推进方式。磁流体推进的基本原理是，通过潜艇内部电机产生强磁场，在与磁场垂直的海水中通以电流，那么在电磁的作用下，海水将产生运动，海水从潜艇运动的相反方向高速喷出，从而推动潜艇前进。超导潜艇具有较强的隐身能力，磁流体推进不需要螺旋浆、减速箱等一些机械装置，不仅减少了潜艇的载荷，而且极大地降低了潜艇的噪声，大大增强了隐身能力。该种艇的机动性能也是无与伦比的，它主要靠改变流体的电流强度和流向… 相似文献
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解决螺旋浆导管内壁侵蚀的重要措施之一是改进吸气导管防蚀装置。本文对导管内流场负压区的分布状况，为防止侵蚀所必需的最佳进气量以及防蚀区域范围的大小等方面，作了深入的分析研究，进而提出防蚀装置的合理结构参数。并对该装置的吸气管径尺度，气嘴的环向配置及其距导管内壁高度，影响结构参量的诸要素均作了详尽的论证，最后提出中小型渔船防蚀装置的最佳结构设计方案，同时还提出检验防蚀装置结构参量是否合理的衡量标准。 相似文献
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本文是在对两国渔业发展情况调查研究的基础上,对比了两国渔船在性能方面的差异,分析了日本渔船的发展趋势,提出了中国渔船近期发展的方向。日本渔船改为节能型后,两国渔船的船型相近,其稳定与适航性指标亦相差不大。日本渔船的装备优于中国的渔船,平均单船功率为46．5kW／艘,中国的平均单船功率为23．03kw／艘。日本渔船的助渔设备、机电设备、制冷设备均较先进,主机推进系统多采用可变螺距螺旋浆或多级减速,中国渔船的推进方式多为定距浆,现在正推广多级减速装置。日本渔船业的发展趋势为：控制规模,提高性能,确保安全,改善适居性。我国渔船的发展方向是：减少渔船的数量,适度发展外海和远洋作业渔船,改善渔船装备,改造小型渔船,大力发展FRP渔船。 相似文献
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缢蛏微卫星序列分离及特性分析 总被引：4，自引：0，他引：4
分析了缢蛏(Sinonovacula constricta)基因组文库中微卫星序列的特性及微卫星引物的遗传特征.采用磁珠富集珐和PCR 筛选法,以CA15为探针,快速分离含有微卫星序列的阳性克隆.结果表明,在筛选的210个白色菌落中,得到58个微卫星序列,阳性克隆率为27.6%,核心重复序列为两碱基和三碱基的微卫星居多,其中完美型占39.7%,非完美型39.7%,复合型占10.3%,非完美型与复合型共存的占10.3%.微卫星重复次数主要集中在20～40次之间,占66%,最高为63次.除探针中使用的CA重复单元外,还观察到AG/TC,AT/TA,AAC/TTG,CAA/GTT,TGA,AAT,AGAA,GTTT/CAAA,AAAT/TTTA,TTTC,CCTA,TCTA,TCCC,TGCC,GTTTCT,CTGTT,CACACC,TATACA,TTTTG的重复序列.利用Primer Premier5.0设计引物24对,经过初步筛选得到适合的微卫星引物18对,为今后未知微卫星标记的开发,群体遗传结构的分析,优良品种的选育提供基础. 相似文献
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The characteristics of the flow over the rudder’s pintle gap are investigated by using the particle image velocimetry (PIV) technique. The propeller and rudder models are scaled down to 1/28.5. Highly accelerated leakage outflows are separated at the discontinuities of the gap and generate strong cavitation at the suction side of the rudder. In the rudder and propeller configuration, the propeller wake sheet ahead of the gap entrance region starts to induce leakage flow over the lower pintle gaps of the suction side. The gap flow has a velocity magnitude as high as 0.4U0 in the high leakage flow condition, where the wake sheet locates over the gap entrance. The cross-flow of the propeller wake sheet interferes the gap entrance region and triggers gap cavitation. As the propeller wake sheet moves downstream and weakens, the gap flow velocity decreases over the gap entrance. 相似文献
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Bu-Geun Paik Ki-Sup Kim Jong-Woo Ahn Kyung-Rae Kim Sang-Uk Lee 《Ocean Engineering》2011,38(13):1495-1502
Rudders of large container ships are easily affected by cavitation, which is well known to be induced by significant axial flows behind a propeller and discontinuities in the rudder. Among several methods to prevent or reduce the cavitation erosion occurred in the rudder, painting is gaining a lot of attention because it can be employed easily and cheaply. To conduct erosion tests properly, the simulation of heavily erosive cavitation is necessary. This can be generated using an inclined propeller dynamometer in the medium-size cavitation tunnel of MOERI (Maritime & Ocean Engineering Research Institute). The inclined shaft of the propeller creates strong cavitation, which occurs around the root of the propeller blade. This cavitation creates impacts through the collapsing process that are very severe, and are useful for realistic and efficient cavitation erosion tests. In the present study, the newly developed cavitation erosion test method is successfully employed to evaluate marine coatings that is mainly composed of epoxy elastomer or silicone polymer material. Silicone polymer-type paint B was found to have three times larger endurance than epoxy elastomer-type paint A. 相似文献
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The horseshoe vortex generated around the sail-body junction of submarine has an important influence on the non-uniformity of submarine wake at propeller disc.The flow characteristics in the horseshoe vortex generated area are analyzed,and a new method of vortex control baffler is presented.The influence of vortex control baffler on the flow field around submarine main body with sail is numerically simulated.The wind tunnel experiment on submarine model is carried out,and it is proved that the vortex control baffler can weaken the horseshoe vortex and decrease the non-uniformity of the wake at propeller disc.It is shown from the experiment results that the effect of vortex control baffler depends on its installation position;with a proper installation position,the non-uniform coefficient of submarine wake would be declined by about 50%;the Reynolds number of submarine model has an influence on the effect of vortex control baffler too,and the higher the Reynolds number is,the better the effect of the vortex control baffler is. 相似文献
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基于C8051F021的智能化风传感器的设计 总被引：1，自引：0，他引：1
介绍了基于美国 Cygnal公司新型、高速 So C( System on Chip)单片机 C80 5 1F0 2 1研制的数字化风速风向传感器。它能自动完成风速、风向参数的采集及处理 ,并以 RS- 2 32 C(或 RS- 485 )的形式输出。实验证明 ,该传感器电路紧凑、性能稳定、功能完善 ,在海洋、陆地气象站有着广泛的应用前景。 相似文献
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Propeller modelling in CFD simulations is a key issue for the correct prediction of hull-propeller interactions, manoeuvring characteristics and the flow field in the stern region of a marine vehicle. From this point of view, actuator disk approaches have proved their reliability and computational efficiency; for these reasons, they are commonly used for the analysis of propulsive performance of a ship. Nevertheless, these models often neglect peculiar physical phenomena which characterise the operating propeller in off-design condition, namely the in-plane loads that are of paramount importance when considering non-standard or unusual propeller/rudder arrangements. In order to emphasize the importance of these components (in particular the propeller lateral force) and the need of a detailed propeller model for the correct prediction of the manoeuvring qualities of a ship, the turning circle manoeuvre of a self-propelled fully appended twin screw tanker-like ship model with a single rudder is simulated by the unsteady RANS solver χnavis developed at CNR-INSEAN; several propeller models able to include the effect of the strong oblique flow component encountered during a manoeuvre have been considered and compared. It is emphasized that, despite these models account for very complex and fundamental physical effects, which would be lost by a traditional actuator disk approach, the increase in computational resources is almost negligible. The accuracy of these models is assessed by comparison with experimental data from free running tests. The main features of the flow field, with particular attention to the vortical structures detached from the hull are presented as well. 相似文献
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本文介绍并叙述了AEL-1型风向、风速仪的设计原理,仪器各部分的电路设计,工作过程及系统软件。该仪器适用于气象台站、工矿企业、海上浮标及科研单位等部门。 相似文献
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SWAN模型中不同风拖曳力系数对风浪模拟的影响 总被引：1，自引：1，他引：0
本文以荷兰哈灵水道海域为实验区域,通过敏感性实验,研究了在14 m/s、31.5 m/s和50 m/s（分别代表一般大风、强热带风暴和强台风的极端条件）定常风速下SWAN模型中不同风拖曳力系数对风浪模拟的影响程度。结果表明,对于近岸浅水区域（水深小于20 m）,风拖曳力系数计算方案的选择对有效波高影响较小,而且当风速增加到一定程度后,波浪破碎成为影响波高值的主要因素;对于深水区域（水深大于30 m）,一般大风条件下风拖曳力系数计算方案的选择对有效波高影响仍然较小,随着风速的继续增大,风拖曳力系数计算方案的选择对有效波高的影响逐渐显著。对于平均周期,风拖曳力系数计算方案的选择和风速的改变对其影响均较小,而由水深变浅导致的波浪破碎对其影响较为显著。根据敏感性实验结果,本文对SWAN模型中风拖曳力系数计算方案的选择做出如下建议:计算近岸浅水区域风浪场或深水区域一般大风条件风浪场时,其风拖曳力系数可以直接采用模型默认选项;而对于深水区域更大风速条件,可首先采用模型默认选项试算,然后结合当地海域实测波浪资料进行修正。 相似文献
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The hydrodynamic characteristics of a marine propeller operating in oblique inflow are investigated by using CFD method. Two propellers with different geometries are selected as the study subjects. RANS simulation is carried out for the propellers working at a wide range of advance coefficients and incidence angles. The effects of axial inflow and lateral inflow are demonstrated with the hydrodynamic force on the propeller under different working conditions. Based on the obtained flow field details, the hydrodynamic mechanism of propeller operating in oblique inflow is analyzed further. The trailing vortex wake of propeller is highly affected by the lateral inflow, resulting in the deflected development path and the circumferentially non-uniform structure, as well as the enhanced axial velocity in slipstream. Different flow patterns are observed on the propeller blade with the variation of circumferential position. Combined with the computed hydrodynamic forces and pressure distribution on propeller, the mechanism resulting in the increase of propulsive loads and the generation of propeller side force is explored. Finally, a systematic analysis is carried out for the propulsive loads and propeller side force as a function of axial and lateral advance coefficients. The major terms that play a dominant role in the modeling of propulsive loads and propeller side force are determined through the sensitivity analysis. This study provides a deeper insight into the hydrodynamic characteristics of propeller operating in oblique inflow, which is useful to the investigation of propeller performance during ship maneuvers. 相似文献