船用柴油机综合保障系统研究

分析了船用柴油机综合保障概念和策略的发展及与柴油机维修性的关系,重点介绍了保障系统中维修计划管理;讨论了计算机辅助船用柴油机综合保障信息系统设计开发过程和系统主要功能模块,开发的原型系统可为进一步的实用系统研制提供参考.     

Numerical Investigation of the Dynamics for Low Tension Marine Cables

This paper presents a numerical investigation into the dynamics of marine cables which are extensively used in offshore industry. In this numerical study, the Euler-Bernoulli beam model is adopted to develop the governing equations of the cable. Bending stiffness is considered to cope with the low tension problem in local area of towing cable, and thus a more accurate solution with the consideration of the axial elongation can be given.The derived strongly-coupled and nonlinear governing equations are solved by a second-order accurate, implicit,and large time step stable central finite difference method. The quadratically convergent Newton-Raphson iteration method is applied to solving the discrete nonlinear algebraic equations. Then a towed array sonar system(TASS)problem is studied. The numerical solutions agree reasonably well with the experimental data and the simulated results of the references. The specified program of the present paper shows great robustness with high efficiency.     

基于空燃比的船舶柴油机碳排放计算方法研究

根据船舶柴油机燃烧产物组分和C、H、O原子守恒规律,首次在空燃比计算模型中直接使用干气体浓度进行计算,并提供了湿气体浓度的修正公式,从而建立排气质量流量计算模型计算碳排放。通过计算与MARPOL公约附则VI修正案(2011)中的简单碳平衡法作了比较分析。最后通过实验验证该计算模型的正确性。因此该计算模型对法规的完善、船舶设计能效管理和船舶营运排放控制有较大的指导意义。     

Modeling Coastal and Marine Environmental Risks in Belize: the Marine Integrated Decision Analysis System (MIDAS)

The livelihood of coastal communities is directly linked to the health of intertidal and marine ecosystems. Coastal zones and marine areas are rapidly changing and highly vulnerable to impacts from climate change, accelerating human development, and over-fishing. Quality of life and the benefits of coastal development can be greatly enhanced, and costs minimized, by projecting and comparing alternative policy outcomes before management decisions are made. This article describes the Marine Integrated Decision Analysis System (MIDAS), an interactive decision support tool designed to assist the users and managers of Belize's system of marine management areas (MMAs) in understanding the interactions among various ecological, socioeconomic, and governance conditions in a spatially explicit manner. MIDAS can simulate and visualize the likely effects of alternative management strategies and therefore provides an important tool for evaluating potential scenarios. We developed two MIDAS modules to address specific threats in Belize –spatial risk resulting from mangrove deforestation in coastal areas and the potential effect of an oil spill off the coast of Belize. Workshops conducted in Belize indicate that diverse user groups such as fishers, tourism operators, and public environmental agencies can successfully utilize MIDAS to understand MMA outcomes, and environmental risks.     

摇摆条件下船用蒸汽蓄热器放汽过程数值研究

基于两流体模型和热相变模型,结合考虑附加惯性力的摇摆计算模型,并引入指数压降放汽边界条件,利用CFX软件进行了摇摆条件下船用蒸汽蓄热器放汽过程数值计算。计算结果显示,在摇摆条件下,蒸汽蓄热器放汽压力和温度均快速降低,但摇摆运动对放汽压力和温度参数影响比较小;摇摆运动加强蒸汽蓄热器内汽水两相流体的湍流交混,诱发蓄热器压力场、速度场和温度场分布紊乱;周期性的摇摆运动导致蒸汽蓄热器水位产生剧烈的周期性波动,且波动周期与摇摆周期基本一致。摇摆模型在蒸汽蓄热器两相流数值模拟中的成功应用,可为海洋条件下蒸汽蓄热器热工水力的准确分析提供参考。     

柴油机水下排气海水倒灌现象的理论分析

柴油机水下排气时存在海水由排气管倒灌入柴油机进而导致柴油机严重损坏的风险。通过分析管内气液两相逆向流动特性和国内外相关研究成果,指出水下排气管内海水倒流的物理机制,并给出了基于Wallis无因次气相速度的水下排气管海水倒流判断准则。进而以某柴油机排气参数为基础,计算分析了排气管管径、排气口水位深度及排气温度等因素对管内倒流界限气速的影响,所得结果对水下排气柴油机防止海水倒灌具有指导意义。     

气象影响舰载固定翼飞机起降的效能评估研究

为定量分析海洋气象环境对航母固定翼舰载机起降的影响,采用量纲分析法分析了影响舰载机起降效能的主要气象因子,以层次分析法为例给出了舰载机起降安全效能评估模型,给出了风、能见度、云底高度对航母固定翼舰载机起降影响的效能评估值,并以一次海雾过程为例,建立了海洋气象环境影响舰载固定翼飞机起降效能的三级评估模型。     

基于BOOST船用柴油机热工故障仿真研究

利用BOOST仿真软件,建立电控化改造后的4190型柴油机工作过程数学模型。该模型的燃烧放热模块采用MCC燃烧模型,传热模块选用Woschni 1978模型,并用该电控柴油机试验数据验证模型的可靠性。结果表明,仿真计算与实验值误差均在2%以内。在此基础上,结合中速电控柴油机的特点,对柴油机在额定工况下喷油定时故障、喷油器喷孔磨损、单缸停油、中冷器效率下降、压气机效率下降及排气阀关闭定时故障进行仿真计算,探索电控柴油机性能指标与热工参数对不同故障的变化规律,从而为船用中速电控柴油机故障监测、诊断提供可行的依据。     

一种新型无线传感器网络在海洋监控系统中的应用

近年来,随着工业的发展和人类海洋活动的日趋频繁,海洋环境问题日益突出。为了实时监控海洋的环境和水文状况,需要采用船舶巡航、人工监控或播撒浮标等方式。然而,由于海面复杂苛刻的自然环境,以及对于人力物力的约束,上述方法无法满足对于海面实时监控的需求。为了解决这一问题,本文提出一种新型无线传感器网络,实时收集并传输相关的数据。该网络由传感器和浮标组成,传感器的数据传输采用无线通信方式,本文对该网络的结构进行研究,并设计了系统原型。     

船舶导航信息系统接口设计

船舶导航信息系统是当代航运中不可或缺的助航设备。随着国际航运业的持续发展,在实时性、稳定性和多用途性等方面,对船舶导航系统提出了更高要求。然而,近年来相关领域的研究主要集中于如何利用最新的GIS和通信定位技术等,实现更加精确、实时的导航功能,对于如何具体设计和实现这样的导航系统研究较少。本文针对当前船舶导航系统的新发展,研究了该系统的实际需求,分析系统需要处理的信息种类和结构,并对导航信息系统中若干关键接口进行了研究和设计,并在此基础上进行了初步的实现和仿真,证明本文提出方案的可行性,同时为今后导航信息系统的设计和制造提供了一定的依据。