共查询到19条相似文献,搜索用时 62 毫秒
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考虑动静干涉的多级透平叶栅大攻角流动特性的三维数值分析 总被引:2,自引:0,他引:2
采用全三维粘性数值模拟技术,利用由Menter基于κ-ω模型和κ-ω模型发展而成的BSL双方程湍流模型(Baseline Model),采用“混合平面”方法传递级间参数,通过求解三维粘性可压缩Favre平均Navier—Stokes方程,对一个考虑应用变几何涡轮技术的舰船动力涡轮三维粘性流场进行了数值研究。变几何涡轮的显著特点是采用可调导叶技术,进而使其透平叶栅可能在大攻角范围内运行。由此通过多级计算,计及动静干涉效应和动叶顶间隙的影响,从而更准确地预测透平叶栅的大攻角流场特性,以期把握变几何涡轮技术的气动设计特点。 相似文献
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柴油机燃烧室的设计,通常以经验设计为主,要通过实机实验,比较得到较优燃烧室形状,周期长,费用高。本文通过模拟不同形状燃烧室内的三维流场,分析缸内气流运动规律,评述了不同燃烧室形状的优缺点。 相似文献
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针对高压涡轮进口气流的特殊条件,采用数值模拟方法.研究了高湍流度、进口总温径向分布不均匀等因素时高压涡轮总体性能和流场的影响规律.研究结果表明,高压涡轮进口总温径向畸变对气动性能影响较小,而进口湍流度从1%到10%逐渐增大,高压涡轮效率降低了约0.4%.但是,在RANS流场模拟中,不同湍流模型,对涡轮性能预测结果有明显差异,由RNGκ-ε模型、κ-ω模型、SST模型以及耦合转捩的SST模型对比表明,不同湍流模型对涡轮效率预测差别最大可达1%,而对叶片表面附面层分离状况预测差别更大,耦合转捩的SST模型预测效果最明显. 相似文献
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船用燃气轮机变几何动力涡轮大攻角流动特性的三维数值模拟 总被引:1,自引:0,他引:1
采用三维数值模拟技术,研究了可调导叶转动导致变几何动力涡轮气动性能变化的流场机理。结果表明,在较小的转角范围内,采用大转折角设计的可调导叶使涡轮处于大攻角运行。在大正攻角或大负攻角下可调导叶级动叶栅流道内的三维分离流场结构及其产生机理有很大差异,而且大正攻角造成的吸力面分离流动更使整个涡轮的效率显著地下降。通过系统的机理分析,提出可调导叶宜采用较小转折角的后部加载叶型,而变几何动力涡轮可调导叶级动叶栅要采用较大负冲角的气动设计原则。 相似文献
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采用TurboGrid对某混流涡轮流道进行网格划分,基于有限元的有线体积法对空间进行离散,采用全隐式耦合求解方法,对三维可压缩流雷诺平均N-S方程和标准k-ε湍流方程进行求解,得出设计工况流场流动特性,结合S3流面的二次流线图,分析了通道涡、角涡、顶隙泄漏涡以及尾缘涡随着流动的发展及耗散过程,描述了轮毂和动叶表面流的流动特性和表面流来源,描述了顶隙泄漏流及尾缘径向窜流的产生过程和流动特性,给出了熵值在转子出口处的分布特点,损失产生的主要因素,结合S1流面的参数分布特点,对子午流道设计的合理性进行评价. 相似文献
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为获得电站水工质跨临界状态下湍流黏性底层的变化规律,基于SST k-ω湍流模型,对跨临界水湍流黏性底层随入口温度、热流密度和质量流速的变化规律进行数值模拟。结果表明:跨临界区水流动的黏性底层厚度并非单调变化,亚临界拐点、伪临界点和超临界拐点是黏性底层厚度和速度梯度变化的关键节点;入口温度仅改变黏性底层厚度和速度梯度的峰、谷值位置,对其大小没有影响;随着质量流速的增大,黏性底层厚度的峰、谷值均减小,速度梯度的峰、谷值均增大;热流密度增大会使黏性底层厚度的峰值增大,但对速度梯度的峰、谷值几乎没有影响。 相似文献
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本文介绍了一个采用湍流双方程模型用于模拟四角切圆炉内等温流场的计算程序,并将计算结果和实验结果作了详细比较,其效果是十分令人满意的,足以满足工程要求。 相似文献
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用CFD研究涡轮静叶栅的二次流损失 总被引:1,自引:1,他引:1
利用CFD软件Fluent对大转折角涡轮叶栅三维流场进行了数值模拟。采用静叶栅前移动的圆柱列替代上游动叶,发现圆柱尾迹进入叶栅流道的位置不同,对叶栅总压损失有较大影响。同时,通道内逐渐增大的横向压力梯度对二次涡发展产生了显著的影响,引起沿流向叶栅总压损失的急剧增大,认为叶高的减小会极大提高叶栅的二次流损失。 相似文献
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Jian JIANG Bo LIU Yangang WANG Xiangyi NAN 《Frontiers of Energy and Power Engineering in China》2008,2(3):320-325
Numerical simulation of three-dimensional turbulent flow in a multistage axial compressor blade row is conducted. A high resolution, third-order ENN scheme is adopted to catch the shockwave and simulate the turbulent flow correctly, while an LU-SGS implicit method is chosen to improve computation rate. A detailed and highly efficient numerical simulation system is thus constructed. The investigation is focused on the grid connecting methods between the rotor and the stator and the corresponding treatment of rotor-stator interactional surface. The final results of a three-stage axial compressor with inlet guide vanes conform well to the experimental data. __________ Translated from Chinese Journal of Applied Mechanics, 2007, 24(1): 21–25 [译自: 应用力学学报] 相似文献
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Numerical 3D model of viscous turbulent flow in one stage gas turbine and its experimental validation 总被引:1,自引:0,他引:1
The paper describes 3D numerical Reynolds Averaged Navier-Stokes (RANS) model and approximate sector approach for viscous turbulent flow through flow path of one stage axial supercharge gas turbine of marine diesel engine. Computational data are tested by comparison with experimental data. The back step flow path opening and tip clearance jet are taken into account. This approach could be applied for variety of turbine theory and design tasks: for offer optimal design in order to minimize kinetic energy stage losses; for solution of partial supply problem; for analysis of flow pattern in near extraction stages; for estimation of rotational frequency variable forces on blades; for sector vane adjustment (with thin leading edges mainly), for direct flow modeling in the turbine etc. The development of this work could be seen in the direction of unsteady stage model application. 相似文献
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Zhuge Weilin Zhang Yangjun Ming Pingwen Lao Xingsheng Chen Xiao 《Frontiers of Energy and Power Engineering in China》2007,1(3):305-310
Investigation into the formation and transport of liquid water in proton exchange membrane fuel cells (PEMFCs) is the key
to fuel cell water management. A three-dimensional gas/liquid two-phase flow and heat transfer model is developed based on
the multiphase mixture theory. The reactant gas flow, diffusion, and chemical reaction as well as the liquid water transport
and phase change process are modeled. Numerical simulations on liquid water distribution and its effects on the performance
of a PEMFC are conducted. Results show that liquid water distributes mostly in the cathode, and predicted cell performance
decreases quickly at high current density due to the obstruction of liquid water to oxygen diffusion. The simulation results
agree well with experimental data.
Translated from J Tsinghua Univ (Sci & Tech), 2006, 46(2): 252–256 [译自: 清华大学学报] 相似文献
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Zhao Qingjun Wang Huishe Zhao Xiaolu Xu Jianzhong 《Frontiers of Energy and Power Engineering in China》2007,1(3):352-358
To reveal the unsteady flow characteristics of a vaneless counter-rotating turbine (VCRT), a three-dimensional, viscous, unsteady
computational fluid dynamics (CFD) analysis was performed. The results show that unsteady simulation is superior to steady
simulation because more flow characteristics can be obtained. The unsteady effects in upstream airfoil rows are weaker than
those in downstream airfoil rows in the VCRT. The static pressure distribution along the span in the pressure surface of a
high pressure turbine stator is more uniform than that in the suction surface. The static pressure distributions along the
span in the pressure surfaces and the suction surfaces of a high pressure turbine rotor and a low pressure turbine rotor are
all uneven. The numerical results also indicate that the load of a high pressure turbine rotor will increase with the increase
of the span. The deviation is very big between the direction of air flow at the outlet of a high pressure turbine rotor and
the axial direction. A similar result can also be obtained in the outlet of a low pressure turbine rotor. This means that
the specific work of a high pressure turbine rotor and a low pressure turbine rotor is big enough to reach the design objectives.
Translated from Journal of Engineering Thermophysics, 2006, 27(1): 35–38 [译自: 工程热物理学报] 相似文献
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本文对一微型燃气轮机向心透平内部的三维流场进行了数值研究。在流场模拟的基础上对原结构的内部流场进行了分析探讨,指出原设计中可以改进的地方并成功的对叶轮进行了改进设计,使向心式透平效率提高了二点几个百分点。 相似文献
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