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基于CFD和气流评价指标的船舶机舱射流通风优化设计 被引量:5
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作者 赵楠 丁亮 祝熠珺 《机电设备》 2017年第6期57-63,共7页
在船舶机舱通风方案设计阶段,通过对某船舶机舱大空间内前后集中和左右集中两种通风口布置方式进行三维CFD模拟,得到机舱内部上下层的气流组织,比较了两种送排风方案对机舱内部流动的影响,表明前后集中送风方式ADPI值更高、回流区更小... 在船舶机舱通风方案设计阶段,通过对某船舶机舱大空间内前后集中和左右集中两种通风口布置方式进行三维CFD模拟,得到机舱内部上下层的气流组织,比较了两种送排风方案对机舱内部流动的影响,表明前后集中送风方式ADPI值更高、回流区更小、无明显气流短路,总体气流组织优于左右集中送风。在此风口布置基础上,进一步引入射流通风系统,仿真结果表明射流通风结合传统送风有效的避免了短路和通风死角,降低了设备局部热点温度约4℃,具有较好的实船应用前景。 展开更多
关键词 机舱通风 CFD仿真 气流评价指标 射流
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Convective Weather Avoidance Prediction in Enroute Airspace Based on Support Vector Machine
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作者 LI Jiahao WANG Shijin +2 位作者 CHU Jiewen LIN Jingjing WEI Chunjie 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第4期656-670,共15页
With the rapid growth of global air traffic,flight delays are increasingly serious.Convective weather is one of the influential causes for flight delays,which has affected the sustainable development of civil aviation... With the rapid growth of global air traffic,flight delays are increasingly serious.Convective weather is one of the influential causes for flight delays,which has affected the sustainable development of civil aviation industry and became a social problem.If it can be predicted that whether a weather-related flight diverts,participants in air traffic activities can coordinate the scheduling,and flight delays can be reduced greatly.In this paper,the weather avoidance prediction model(WAPM)is proposed to find the relationship between weather and flight trajectories,and predict whether a future flight diverts based on historical flight data.First,given the large amount of weather data,the principal component analysis is used to reduce the ten dimensional weather indicators to extract 90%information.Second,the support vector machine is adopted to predict whether the flight diverts by determining the hyperparameters c and γ of the radial basis function.Finally,the performance of the proposed model is evaluated by prediction accuracy,precision,recall and F1,and compared with the methods of the k nearest neighbor(kNN),the logistic regression(LR),the random forest(RF)and the deep neural networks(DNNs).WAPM’s accuracy is 5.22%,2.63%,2.26%and 1.03%greater than those of kNN,LR,RF and DNNs,respectively;WAPM’s precision is 6.79%,5.19%,4.37%and 3.21%greater than those of kNN,LR,RF and DNNs,respectively;WAPM’s recall is 4.05%,1.05%,0.04%greater than those of kNN,LR,and RF,respectively,and 1.38%lower than that of the DNNs;and F1 of WAPM is 5.28%,1.69%,1.98%and 0.68%greater than those of kNN,LR,RF and DNNs,respectively. 展开更多
关键词 convective weather avoidance prediction data mining evaluation indicator enroute airspace
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