共查询到19条相似文献,搜索用时 140 毫秒
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通过对超音速透平叶栅流动进行详细的数值模拟,分析叶栅通道中激波与附面层的相互作用.通过对流道中静压、马赫数等参数的研究,综合分析压比和栅距的变化对叶栅中激波系、激波与附面层的相互作用的影响,并将部分模拟结果与实验数据进行了比较. 相似文献
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应用流动计算分析软件CFX,对某大型汽轮机末级动叶顶部截面叶型的跨音速流动进行了数值模拟研究,分析叶栅中激波结构特征和流动损失机理.采用3阶Bezier曲线表达叶型中弧线,2阶与3阶Bezier曲线组合表达叶型厚度分布,结合Kriging代理模型优化叶型,改善气动性能.结果 表明:末级动叶顶部截面叶型气动损失主要与激波强度及其反射位置有关;叶型优化后,叶栅内激波强度减弱,相比原叶型,激波损失减少约32%,同时削弱了激波对边界层的影响,边界层损失降低约17%;优化叶型总压损失下降24%,气动性能明显提高. 相似文献
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本文采用组合多项式曲线构造了具有高亚音进口条件的大折转角压气机静叶叶型,探索了进一步提高跨音速压气机负荷时,静叶根部区域可能存在的激波结构和损失特征.采用数值模拟方法对不同条件下的高亚音速大折转角压气机叶栅流场进行了数值模拟,结果表明:叶栅内的激波结构与进口马赫数、攻角以及叶型的转角等参数密切相关.通过对叶栅出口的损失分析发现,激波与附面层相互作用改变了原有附面层内的损失分布规律,形成了由激波强度和位置所决定的沿叶片表面法线方向大小基本不变的高损失区域,叶型损失的大小和激波与吸力面最低压力点之间的相对位置密切相关. 相似文献
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基于定常RANS方程,采用Spalart-Allmaras(S-A)湍流模型,数值模拟某跨音速导叶尾缘劈缝射流的定常流动结构,分析尾缘劈缝射流对尾缘激波结构、尾迹流动特性及叶栅气动性能的影响。研究表明:开缝射流显著降低尾缘压力面侧燕尾波强度,并使激波在相邻叶片吸力面入射点向上游移动;当叶栅出口马赫数小于1.35时射流使吸力面燕尾波强度减弱,而达到1.35后射流使该侧激波强度增大;在不同出口马赫数下射流均能降低叶栅动能损失。 相似文献
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为了研究缩放喷管中湿蒸汽的自发凝结流动,对某Laval喷管中的几何参数及实验工况进行喷管中湿蒸汽凝结两相流动的三维数值模拟。通过以数值模拟结果结合部分工况的压力实验数据进行对比,讨论了喷管中蒸汽自发凝结流动的物理现象。 相似文献
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为了了解超燃冲压发动机中三维斜激波与壁面的相交情况,以冷态模拟为基础,对两种不同形状的斜劈结构产生的斜激波进行数值模拟。当斜劈展向与气流方向成45.0°时,激波和膨胀波结构呈现三维特性,并且激波在两侧壁面处的反射现象不同。以激波面上游为视角,当激波与壁面相交成锐角时会产生马赫反射;而激波与壁面相交成钝角则会以叠加膨胀波的形式减弱激波,并且使激波面的法线方向与壁面的法线方向垂直。由于两侧壁面的影响,随着高度的增加激波强度减弱,同时气体经过斜激波后偏转角度也减小。对于构型Ⅱ,有斜劈的区域产生三维斜激波会延伸到无斜劈区域,此时下壁面与斜激波相交成钝角,同样会以叠加膨胀波的形式减弱斜激波。 相似文献
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A two-dimensional compressible numerical model, in which the thermodynamic state and properties of steam were calculated by the Virial equation, was developed and used to predict the spontaneous condensation phenomenon with homogeneous nucleation in a series of Laval nozzles. The validation of the numerical results was accomplished with the experiment conducted by Moore and the results showed good agreement between numerical simulation and the experiment data. Based on the simulation, the nonequilibrium thermodynamic phenomenon, the condensation shock, and the aerodynamic shock were studied and the difference between the condensation shock and the aerodynamic shock was investigated. In addition, the influence of the aerodynamic shock on the nonequilibrium phase change was revealed. 相似文献
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The spontaneous nucleation flow in turbine cascade was numerically studied. The model was implemented within a full Navier–Stokes viscous flow solution procedure and the process of condensation was calculated by the quadrature method of moments that shows good accuracy with very broad size distributions. Results were presented for viscous and inviscous flow, showing the influence of boundary layer separation and wake vortices on spontaneous nucleation. The results show that the degree of flow separation in wet steam flow is greater than that in superheated steam flow due to condensation shock and that the loss cannot be neglected. Furthermore, the impact of boundary layer separation and wake vortices on velocity profiles and its implications for profile loss were considered. The calculations showed that layer separation and wake vortices influence nucleation rate, leading to different droplet distributions. A method for controlling homogeneous nucleation and for reducing degree of flow separation in high-speed transonic wet steam flow was presented. The liquid phase parameter distribution is sensitive to the suction side profile of turbine cascade, which impacts the nucleation rate distribution leading to different droplet distributions and affects the degree of flow separation. The numerical study provides a practical design method for turbine blade to reduce wetness losses. 相似文献
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Liansuo An Zhi Wang Zhonghe Han 《Frontiers of Energy and Power Engineering in China》2009,3(3):254-261
The spontaneous nucleation flow in turbine cascade was numerically studied. The model was implemented within a full Navier-Stokes
viscous flow solution procedure and the process of condensation was calculated by the quadrature method of moments that shows
good accuracy with very broad size distributions. Results were presented for viscous and inviscous flow, showing the influence
of boundary layer separation and wake vortices on spontaneous nucleation. The results show that the degree of flow separation
in wet steam flow is greater than that in superheated steam flow due to condensation shock and that the loss cannot be neglected.
Furthermore, the impact of boundary layer separation and wake vortices on velocity profiles and its implications for profile
loss were considered. The calculations showed that layer separation and wake vortices influence nucleation rate, leading to
different droplet distributions. A method for controlling homogeneous nucleation and for reducing degree of flow separation
in high-speed transonic wet steam flow was presented. The liquid phase parameter distribution is sensitive to the suction
side profile of turbine cascade, which impacts the nucleation rate distribution leading to different droplet distributions
and affects the degree of flow separation. The numerical study provides a practical design method for turbine blade to reduce
wetness losses. 相似文献
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INTRODUCTIONThehomogeneousnucleationwithsubsequentspon-taneouscondensationofwater,pentanol,andethanolVaPorsinacarriergasareinvestigatedexperimen-tallyandtheoreticallyintheexpansionpartofashocktube.AswasshownbySislianandGlass(l976)forsupercriticalconditionsthecondensationshockwave(Cw)occurs.Thehomogeneousnucleationofwatervaporinacarriergaswasfirststudiedexperimentallyintheex-pansionpartofashocktubeusinglightscatteringbyBarschdorff(1975)andthenumericalsolutionwasaddedbySislianandGlaJss(1… 相似文献
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Based on the two-phase wet steam flow with spontaneous condensation,experimental verification and flow analysis on nozzle and 2D cascade are carried out.The 3D Reynolds-Averaged gas-liquid two-phase flow control equation solver is explored with k ε k p turbulence model.Furthermore,3D flow numerical simulation on the last stage stator of the steam turbine is carried out.The results show that a sudden pressure rise on blade suction surface is mainly caused by the droplet growth in condensation flow.The more backward the condensation position is in cascade passage,the less the sudden pressure rise from condensation is,and the larger the nucleation rate is,the maximum under-cooling and the number of droplets per unit volume are.Interaction of condensation wave and shock wave has imposed greater influence on the parameters of the blade cascade outlet. 相似文献
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针对AP1000核电厂安全级设备鉴定设计基准事故(DBA)模拟试验第1s热冲击过程,构建了过热蒸汽由储汽罐充入试验仓的模型.利用Fluent流体计算软件对瞬态热冲击过程进行了数值模拟,得到试验系统内气体温度、压力、流速、组分质量分数瞬态变化过程及其空间分布状态.结果表明:超音速蒸汽射流进入试验仓,经挡板减速并改变方向,与仓内空气混合,同时压缩空气,使仓内介质温度和压力快速上升并达到要求值;试验仓内瞬态压力分布均匀,但温度分布取决于蒸汽的流动,随着蒸汽不断充满试验仓,1s后仓内温度分布趋于均匀;储汽罐释放高温高压过热蒸汽充入试验仓的工艺可以满足DBA试验第1s热冲击试验要求. 相似文献
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Liangju ZHAO Fei WANG Hong GAO Jingwen TANG Yuexiang YUAN 《Frontiers of Energy and Power Engineering in China》2008,2(3):344-347
The shock wave of vapor-liquid two-phase flow in a pressure-gain steam injector is studied by building a mathematic model
and making calculations. The results show that after the shock, the vapor is nearly completely condensed. The upstream Mach
number and the volume ratio of vapor have a great effect on the shock. The pressure and Mach number of two-phase shock conform
to the shock of ideal gas. The analysis of available energy shows that the shock is an irreversible process with entropy increase.
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Translated from Nuclear Power Engineering, 2007, 28(4): 25–28 [译自: 核动力工程] 相似文献