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Jingjing ZHU Xiaojun WANG Haiguo ZHANG Yuwen LI Ruixing WANG Zhiping QIU 《中国航空学报》2019,32(9):2095-2108
Lightweight design is important for the Thermal Protection System(TPS) of hypersonic vehicles in that it protects the inner structure from severe heating environment. However, due to the existence of uncertainties in material properties and geometry, it is imperative to incorporate uncertainty analysis into the design optimization to obtain reliable results. In this paper, a six sigma robust design optimization based on Successive Response Surface Method(SRSM) is established for the TPS to improve the reliability and robustness with considering the uncertainties. The uncertain parameters related to material properties and thicknesses of insulation layers are considered and characterized by random variables following normal distributions. By employing SRSM, the values of objective function and constraints are approximated by the response surfaces to reduce computational cost. The optimization is an iterative process with response surfaces updating to find the true optimal solution. The optimization of the nose cone of hypersonic vehicle cabin is provided as an example to illustrate the feasibility and effectiveness of the proposed method. 相似文献
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为了获得弯曲/倾斜导叶对大展弦比低压涡轮气动性能的影响,通过求解基于耦合转捩SST湍流模型的雷诺平均N-S方程组,对GE-E3低压涡轮叶栅的进行了全三维粘性定常与非定常数值模拟。研究了弯曲/倾斜导叶对涡轮级效率的影响,分析了对导叶叶栅气动性能、导叶扩散因子与边界层发展的作用,以及对下游动叶气动性能和动叶吸力面流动特性的影响。结果表明,正弯导叶减小了二次流损失却带了更大的叶型损失,降低了涡轮级效率,而正倾斜改变了上下端壁的二次流损失分配,对总的叶型损失影响较小,在一定角度下能够改善大展弦比涡轮叶栅的气动性能。 相似文献
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再入机动飞行器数学仿真研究 总被引:5,自引:0,他引:5
本文讨论了再入机动飞行器三自由度和六自由度仿真和分析。三自由度仿真研究了再入机动飞行器的导引规律和减速控制规律,证明了其合理性,且精度是满足要求的。而六自由度仿真说明了飞行器再入过程中虽然有静稳定和静不稳定交替出现的飞行状态,且动压变化大,如控制系统和制导方法设计良好,其精度仍可满足要求 相似文献
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针对某航空高强钢零件大尺寸面轮廓度数控加工合格率较低问题,利用精益6σ方法,依据DMAIC的研究路径,充分运用箱线图、等方差检验、单因子方差分析等方法和工具,分析了“人、机、料、法、环、测”6大方面的操作者、加工刀具、装夹方式、主轴转速、切削量、进给速度、切削方式7个因素,确定刀具尺寸、切削量、进给速度为关键影响因素;通过建立面轮廓度与7个影响因素之间的GLM模型,得出影响流程输出的3个关键影响因素的最佳组合,并在此基础上对工艺参数进行优化。结果表明:该零件的数控加工工艺流程改进后,减少了加工过程中的人工调试检查环节,缩短了加工调试验证时间,大尺寸面轮廓度数控加工合格率从80%提高到96%以上,取得了较好的经济效益。 相似文献
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为了研究中心分级贫油低排放燃烧室的排放特性和排放预测方法,针对一个低排放头部方案,在单头部燃烧室试验件上,在不同的温度、压力、油气比、供油模式和分级比条件下,测量其排放性能。以Lefebvre排放经验预测公式为基础,采用经验分析方法拟合排放试验数据,归纳出适用于本头部方案的排放预测公式。表征预测好坏的判定系数R2在小工况下和大工况下分别为0.95和0.93,表明预测结果与试验结果符合度较好。小工况和大工况排放特性不同,对仅预燃级喷油的小工况工作模式,NO_x排放主要受化学恰当燃烧温度和预燃级局部当量比的影响;对预燃级和主燃级同时喷油的大工况工作模式,NO_x排放主要受燃烧区温度和主燃级燃油比例的影响。 相似文献
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This study is concerned with the experimental and theoretical investigation of the combustion instabilities in a premixed swirl combustor. It is focused on the effects of the swirl mixing distance on the intrinsic thermoacoustic mode. The swirler as an origin of the swirling flow is also the source of the flow disturbance, which has effects on the flame response. The location of the swirler is varied in the experiment to study the effect on combustion instabilities and flame transfer functions. ... 相似文献
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本文结合我国大型军工企业的实际情况,重点阐述在生产制造领域和产品成本领域推行精益化管理的基本内容,以及精益生产方式与传统生产方式的比较。 相似文献
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