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组合多面体理论及几何构型设计 被引量:6
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作者 舒畅 周丰峻 +1 位作者 梁斌 刘士珍 《河南科技大学学报(自然科学版)》 CAS 2007年第6期53-56,共4页
根据目前国内网壳形式的现状,提出了一种全部由五边形和六边形网格组成的网壳形式(以下简称组合多面体)。本文首先论述了组合多面体的几何性质,其几何性质的对称性和均匀性为它的实际应用提供了前提条件;然后又总结了这种组合多面体的... 根据目前国内网壳形式的现状,提出了一种全部由五边形和六边形网格组成的网壳形式(以下简称组合多面体)。本文首先论述了组合多面体的几何性质,其几何性质的对称性和均匀性为它的实际应用提供了前提条件;然后又总结了这种组合多面体的面数计算公式,说明这样的组合多面体有无穷多个;之后根据节点突角和相等原理,分别算出了32面体,42面体,92面体,122面体的六边形构型,节点构型,杆长类型和突角和,又列出了162面体,252面体,272面体,482面体,752面体的这种性质,进而总结了这些特性间的关系,为组合多面体的建模提供了依据。 展开更多
关键词 组合多 几何性质 面数计算 节点突角特性
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Quantitative analysis on influencing factors for interface propagation-based thermal conductivity measurement method during solid-liquid transition 被引量:1
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作者 ZHOU Tian MA Xiao-yi +1 位作者 LIU Xu LI Yuan 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第8期2041-2055,共15页
The recently proposed interface propagation-based method has shown its advantages in obtaining the thermal conductivity of phase change materials during solid-liquid transition over conventional techniques. However, i... The recently proposed interface propagation-based method has shown its advantages in obtaining the thermal conductivity of phase change materials during solid-liquid transition over conventional techniques. However, in previous investigation, the analysis on the measurement error was qualitative and only focused on the total effects on the measurement without decoupling the influencing factors. This paper discusses the effects of influencing factors on the measurement results for the interface propagation-based method. Numerical simulations were performed to explore the influencing factors, namely model simplification, subcooling and natural convection, along with their impact on the measurement process and corresponding measurement results. The numerical solutions were provided in terms of moving curves of the solid-liquid interface and the predicted values of thermal conductivity. Results indicated that the impact of simplified model was strongly dependent on Stefan number of the melting process. The degree of subcooling would lead to underestimated values for thermal conductivity prediction. The natural convection would intensify the heat transfer rate in the liquid region, thereby overestimating the obtained results of thermal conductivity. Correlations and experimental guidelines are provided. The relative errors are limited in ±1.5%,±3%and ±2% corresponding to the impact of simplified model, subcooling and natural convection, respectively. 展开更多
关键词 phase change material thermal conductivity measurement influencing factor interface propagation-based method numerical simulation
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Effect of flank angle and friction coefficient on contact stress of turbine rotor 被引量:2
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作者 WU Xiao-zan TAO Qing-bin +1 位作者 CHEN An-ping XU Hui 《Journal of Central South University》 SCIE EI CAS 2013年第7期1792-1796,共5页
In order to simulate the stress of turbine rotor in aeroengine, based on the ANSYS, the simplification model of the turbine rotor was built up. By applying the simplification model, the contact stress of turbine rotor... In order to simulate the stress of turbine rotor in aeroengine, based on the ANSYS, the simplification model of the turbine rotor was built up. By applying the simplification model, the contact stress of turbine rotor was computed. The maximum contact stress appears at the chamfer below the flank, which agrees with experiment result. At the same time, the contact stress changing with the flank angle and friction coefficient was calculated, The results show that the contact stress in the flank increases slowly with the increase of flank angle; with the friction coefficient increasing, the contact stress in flank length decreases; the contact stress will not change when the friction coefficient is over 0.25. 展开更多
关键词 AEROENGINE contact stress ANSYS optimization design
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Crosswind stability of high-speed trains in special cuts 被引量:3
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作者 张洁 高广军 +1 位作者 刘堂红 李志伟 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第7期2849-2856,共8页
Analysis of the aerodynamic performance of high-speed trains in special cuts would provide references for the critical overturning velocity and complement the operation safety management under strong winds.This work w... Analysis of the aerodynamic performance of high-speed trains in special cuts would provide references for the critical overturning velocity and complement the operation safety management under strong winds.This work was conducted to investigate the flow structure around trains under different cut depths,slope angles using computational fluid dynamics(CFD).The high-speed train was considered with bogies and inter-carriage gaps.And the accuracy of the numerical method was validated by combining with the experimental data of wind tunnel tests.Then,the variations of aerodynamic forces and surface pressure distribution of the train were mainly analyzed.The results show that the surroundings of cuts along the railway line have a great effect on the crosswind stability of trains.With the slope angle and depth of the cut increasing,the coefficients of aerodynamic forces tend to reduce.An angle of 75°is chosen as the optimum one for the follow-up research.Under different depth conditions,the reasonable cut depth for high-speed trains to run safely is 3 m lower than that of the conventional cut whose slope ratio is 1:1.5.Furthermore,the windward slope angle is more important than the leeward one for the train aerodynamic performance.Due to the shield of appropriate cuts,the train body is in a minor positive pressure environment.Thus,designing a suitable cut can contribute to improving the operation safety of high-speed trains. 展开更多
关键词 high-speed train crosswind stability cut pressure distribution numerical simulation
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