共查询到18条相似文献,搜索用时 370 毫秒
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《自动化仪表》2019,(3)
航空发动机燃烧室出口径向温度分布、出口周向温度分布的研究对燃烧室十分重要。利用试验测得燃烧室出口温度径向、周向分布的数据,可以得到燃烧室气动性能的各种数据。为适应某单头部燃烧室出口温度的测量需求,借鉴涡轮叶片的冷却设计方法,设计了一种适用于燃烧室出口温度测量的气冷温度探针。应用CFX软件对气冷温度探针的冷却效果进行了详细分析,借助Workbench软件对气冷温度探针结构强度进行了详细计算,使冷却效果和强度安全储备系数满足使用要求。该气冷温度探针在某单头部燃烧室试验中得到了应用,试验最高温度达到2 005 K。试验结果表明,气冷温度探针冷却效果、结构强度均满足使用要求,与计算结果一致。该研究为气冷温度探针设计提供了一种可靠的新方法。 相似文献
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发动机部件强度和刚度评价及疲劳分析 总被引:1,自引:0,他引:1
某汽油机开发阶段须对发动机各主要部件结构强度和刚度做全面评价,并且须考核缸盖缸体的高周疲劳性能.基于STAR-CCM+计算出水套内部气体温度和对流换热系数,将其映射到水套有限元网格表面上作为温度边界条件.得到整个机体的温度场分布以后,在考虑各部件接触非线性的基础上,得到机体各部件的应力和变形等结果并进行评价.在有限元分析结果的基础上考虑材料温度非线性,考察缸体缸盖疲劳安全因数.结果表明,缸盖局部应力偏大,下缸体与油底壳接触面局部间隙过大,缸体缸盖疲劳安全性能满足要求. 相似文献
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发动机进气调节系统是为发动机的测试建立一个标准的大气状况环境。研究了基于计算机技术的发动机进气调节系统的设计与实现,讨论了应用PID调节器和模糊控制理论实现压力和温度调控的理论与方法。该系统已运用于发动机生产与测试部门,达到了预期的效果。 相似文献
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汽车发动机热工性能测试系统设计 总被引:1,自引:0,他引:1
本文针对汽车发动机测试中热工性能指标的测试需求,设计了一套测试系统,该系统可在线检测汽车发动机的温度、压力、流量等参数,实际应用表明,该系统测试精度高,性能稳定,由于采用了分层设计和总线技术,系统扩充方便,可满足多参数的在线测试. 相似文献
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The paper deals with the optimization problem of packing identical spheres into a cylinder of minimal height. A mathematical model of the problem is constructed and its characteristics are considered. On the ground of characteristics, a strategy of searching for an approximation to a global minimum is offered. The strategy includes a special search tree construction, a modification of the Zoutendijk method of feasible directions to calculate local minima, and a modification of the decremental neighborhood method to search for an approximation to a global minimum. Numerical examples and performance analysis of solutions are given. On the basis of the mathematical model and numerical experiment, a number of conclusions are drawn. 相似文献
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The steady flow around and through a porous circular cylinder was studied numerically. The effects of the two important parameters, the Reynolds and Darcy numbers, on the flow were investigated in details. The recirculating wake existing downstream of the cylinder is found to either penetrate into or be completely detached from the cylinder. It is also found that, contrary to that of the solid cylinder, the recirculating wake develops downstream of or within the porous cylinder, but not from the surface of it. These new findings provide additional evidence to Leal’s conclusion (Leal LG. Vorticity transport and wake structure for bluff bodies at finite Reynolds number. Phys Fluids A 1989;1:124) that the appearance of recirculating wakes at finite Reynolds number is due to vorticity accumulation, but not a result of the same physical phenomena associated with separation in boundary layers in adverse pressure gradients. Also presented in the current study are the variation of the critical Reynolds number for the onset of a recirculating wake as a function of Darcy number and the variation of a newly defined parameter, the penetration depth, as a function of the Reynolds number and Darcy number. 相似文献
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为了提高气缸运行的平稳性,提出了一种基于灰色预测PID控制方法.给出了灰色预测PID控制结构,设计了灰色预测PID控制器,并在灰色预测理论所形成新误差序列的基础上,导出了校正PID参数表达式;接着,对输出预测进行滤波处理,以消除预测值偏高的不足;然后,搭建了气缸运动控制实验系统并进行了测试实验.结果表明:相对于常规PID控制,灰色预测PID控制的气缸运行过程中速度超调量由22.1%降至7.8%;速度波动范围由±6.2%降至±2.1%.采用灰色预测PID控制的气缸运行过程中速度超调和振荡问题有了明显改善,满足了大多数场合的应用要求. 相似文献