A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and tempera...A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5m in diameter, 90m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results. The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss.展开更多
A combined arrival and departure scheduling problem is investigated for multi-airport system to alleviate the problem of airspace congestion and flight delay.Firstly,the combined scheduling problem for multi-airport s...A combined arrival and departure scheduling problem is investigated for multi-airport system to alleviate the problem of airspace congestion and flight delay.Firstly,the combined scheduling problem for multi-airport system is defined through in-depth analysis of the characteristics of arrival and departure operations.Then,several constraints are taken into account,such as wake vortex separation,transfer separation,release separation,and separation in different runway operational modes.Furthermore,the scheduling model is constructed and simulated annealing algorithm is proposed by minimizing the total delay.Finally,Shanghai multi-airport system is chosen to conduct the simulation and validation.And the simulation results indicate that the proposed method is able to effectively improve the efficiency of arrival and departure operations for multi-airport system.展开更多
针对区域防空反导作战中各要素复杂耦合所导致的战场态势快速演变、来袭目标数量动态变化等难题,提出一种基于可动态扩展且带时空推理的QMIX(QMIX with Dynamic extension and Spatiotemporal reasoning, QMIX-DS)的火力分配方法,以火...针对区域防空反导作战中各要素复杂耦合所导致的战场态势快速演变、来袭目标数量动态变化等难题,提出一种基于可动态扩展且带时空推理的QMIX(QMIX with Dynamic extension and Spatiotemporal reasoning, QMIX-DS)的火力分配方法,以火力单元作为智能体构建决策网络,生成火力分配策略。核心改进为:为每个智能体的决策网络设计可动态扩展特征编码模块,自适应处理数量变化的来袭目标,并引入对比学习突出目标类别属性,形成差异化特征表征;构建两层多头自注意力机制捕捉不同类别目标间的动态时空依赖关系,快速推理任务过程中的态势演变,优化火力分配策略。基于墨子平台不同规模的仿真结果表明,所提出的火力分配方法能够在动态变化的战场条件下生成有效的防空反导策略,与基线算法及其他主流算法相比,所提QMIX-DS算法在目标拦截率、阵地存活率、导弹消耗数量等指标上均体现出了优势,并在不同场景中展现出较高的扩展性和泛化性。展开更多
文摘A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5m in diameter, 90m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results. The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss.
基金supported by the National Natural Science Foundation of China(No.71401072)the National Natural Science Foundation of Jiangsu Province(No.BK20130814)the Foundation of Jiangsu Innovation Program for Graduate Education(the Fundamental Research Funds for the Central Universities,No.SJLX15_0128)
文摘A combined arrival and departure scheduling problem is investigated for multi-airport system to alleviate the problem of airspace congestion and flight delay.Firstly,the combined scheduling problem for multi-airport system is defined through in-depth analysis of the characteristics of arrival and departure operations.Then,several constraints are taken into account,such as wake vortex separation,transfer separation,release separation,and separation in different runway operational modes.Furthermore,the scheduling model is constructed and simulated annealing algorithm is proposed by minimizing the total delay.Finally,Shanghai multi-airport system is chosen to conduct the simulation and validation.And the simulation results indicate that the proposed method is able to effectively improve the efficiency of arrival and departure operations for multi-airport system.
文摘针对区域防空反导作战中各要素复杂耦合所导致的战场态势快速演变、来袭目标数量动态变化等难题,提出一种基于可动态扩展且带时空推理的QMIX(QMIX with Dynamic extension and Spatiotemporal reasoning, QMIX-DS)的火力分配方法,以火力单元作为智能体构建决策网络,生成火力分配策略。核心改进为:为每个智能体的决策网络设计可动态扩展特征编码模块,自适应处理数量变化的来袭目标,并引入对比学习突出目标类别属性,形成差异化特征表征;构建两层多头自注意力机制捕捉不同类别目标间的动态时空依赖关系,快速推理任务过程中的态势演变,优化火力分配策略。基于墨子平台不同规模的仿真结果表明,所提出的火力分配方法能够在动态变化的战场条件下生成有效的防空反导策略,与基线算法及其他主流算法相比,所提QMIX-DS算法在目标拦截率、阵地存活率、导弹消耗数量等指标上均体现出了优势,并在不同场景中展现出较高的扩展性和泛化性。
