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真空导入成型工艺(VIMP)广泛应用于复合材料游艇艇体制造,然而其浇注系统在工程上仍然主要根据经验或多次试验来设置。论文基于数值模拟技术,对游艇艇体VIMP工艺浇注系统的优化方法进行了研究。通过对充模过程和流道布置方式的分析,提出了流道布置方案评价方法;通过对四种不同流道布置方式的树脂充模过程进行仿真,确定了最佳的流道布置方式。研究了游艇艇体VIMP工艺浇口位置优化方法,确定了优化目标和优化参数,建立了优化浇口位置的数学模型;并通过一系列的树脂充模过程模拟,仿真拟合出浇口位置优化目标函数的具体形式,进而获得浇口位置的最优值。数值分析结果同时表明:仅采用增加浇口数量的方法,达不到既能降低充模时间同时又能避免充模缺陷的目的。 相似文献
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针对SUBX潜艇模型,采用数值计算手段,开展附体对潜艇阻力及尾部伴流场的影响分析。计算表明,附体导致潜艇粘压阻力的显著增加,以及伴流场不均匀性的产生。稳定翼对桨盘面半径内伴流场不均匀性的影响较大,而指挥室围壳主要影响桨盘面半径外伴流场不均匀性。从降低阻力和改善伴流场角度考虑,需开展附体外形、位置及与主艇体连接形式的深入研究。 相似文献
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针对电容去离子(CDI)海水淡化单元,建立了单元内吸、脱附过程的多物理场耦合模型,通过模拟分析了吸附及两种脱附方式(电压断开和电压反接)下,操作参数(工作电压、入口流速)和几何参数(电极厚度、流道间距)对CDI单元吸附脱盐及脱附再生过程的影响规律。结果表明,吸附效率随入口流速及流道间距的增大而减小,随多孔电极厚度及极板电压的增大而增大;吸附过程中,最小出口浓度随入口速度和流道间距的增大而增大,随工作电压增加而减小,与电极厚度无关;与脱附方式为电压断开相比,脱附方式为电压反接时,脱附完成所需时间较小。 相似文献
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In this study, we carried out model tests to investigate the ice failure process and the resistance experienced by a transport vessel navigating in the Arctic region in pack ice conditions. We tested different navigation velocities, ice plate sizes, and ice concentrations. During the tests, we closely observed several phenomena, including the modes of interaction of the ice ship and the moving and failure modes of ice. We also measured the vessel resistances under different conditions. The test results indicate that the navigation velocity is a significant determinant of the moving and failure modes of ice. Moreover, vessel resistance is remarkably dependent on the ice concentration and navigation velocity. The variances of the mean and maximum resistance are also compared and discussed in detail. 相似文献
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《船舶与海洋工程学报》2016,(3)
In this study, we carried out model tests to investigate the ice failure process and the resistance experienced by a transport vessel navigating in the Arctic region in pack ice conditions. We tested different navigation velocities, ice plate sizes, and ice concentrations. During the tests, we closely observed several phenomena, including the modes of interaction of the ice ship and the moving and failure modes of ice. We also measured the vessel resistances under different conditions. The test results indicate that the navigation velocity is a significant determinant of the moving and failure modes of ice. Moreover, vessel resistance is remarkably dependent on the ice concentration and navigation velocity. The variances of the mean and maximum resistance are also compared and discussed in detail. 相似文献
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以世界上较为通用的破片模拟弹作为高强聚乙烯层合板的防御对象,利用高速摄影技术得到了破片的具体侵彻过程,并通过弹道试验,得到了弹道极限和剩余速度的试验值。试验后的靶板变形模式和吸能机理表明:高强聚乙烯层合板在弹道极限附近的防护效率最高。根据试验结果拟合得到了不同面密度下的靶板弹道极限和剩余速度的经验公式,并比较了经验公式和经典公式计算值与试验结果,前者与试验结果吻合较好。 相似文献
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本文对两种不同入口型式的水力旋流器的流场进行了数值模拟,湍流模型采用雷诺应力模型,并结合油-水两相流MIXTURE混合模型进行分析,得出:单入口旋流器流场切向速度、轴向速度呈偏心分布,而切向双入口型式的旋流器流场分布对称性明显优于单入口型式;切向双入口旋流器在油-水两相分离时,油相浓度沿着径向方向变化率更大,且更易于向中心区汇聚,利于分离,分离效率要高于单入口旋流器;实验结果证明了模拟结果的正确性。 相似文献
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The efficient integration of logistics modes is critical for international cargo shipping. The local transportation connecting to the export port then plays a vital role in such integration. This paper investigates the problems of carrier selection in the China Pearl River delta area, with respect to international shipping. The analytical hierarchy process (AHP) model is constructed based on a comprehensive industrial interviews and statistical analysis. Rather than simply ranking the given alternatives, we use AHP is used to analyse the weakness and strength of impacting factors in carrier selection. The model is implemented under different types of shipper. Seven criteria are statistically summarized from the questionnaire for evaluating eight different modes. The results are useful to those liner companies serving the PRD region in relationship to port selection and fleet deployment. 相似文献
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The efficient integration of logistics modes is critical for international cargo shipping. The local transportation connecting to the export port then plays a vital role in such integration. This paper investigates the problems of carrier selection in the China Pearl River delta area, with respect to international shipping. The analytical hierarchy process (AHP) model is constructed based on a comprehensive industrial interviews and statistical analysis. Rather than simply ranking the given alternatives, we use AHP is used to analyse the weakness and strength of impacting factors in carrier selection. The model is implemented under different types of shipper. Seven criteria are statistically summarized from the questionnaire for evaluating eight different modes. The results are useful to those liner companies serving the PRD region in relationship to port selection and fleet deployment. 相似文献