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中国电机工程学报 2008, 28(35) 57-65 DOI:
ISSN: 0258-8013 CN: 11-2107/TM |
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| 工程热物理 |
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涡旋射流控制扩压器分离流动的大涡模拟 |
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樊涛 谢永慧 张荻 |
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西安交通大学能源与动力工程学院 西安交通大学能源与动力工程学院 西安交通大学能源与动力工程学院 |
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摘要：
为研究涡旋射流对湍流边界层分离控制的机理，基于大涡模拟方法建立了具有涡旋射流、扩张角为14°的圆锥扩压器数值分析模型，计算结果与相应试验数据吻合良好，验证了计算模型的合理性与精确性。通过对特征截面上流场参数的详细分析，获得了射流导致的复杂涡系形成过程，发现了射流孔附近的强涡来源于剪切层涡，剪切层涡经过破碎和耗散，在射流下游近区发展为强弱不对称的反向涡对，在下游远区形成一个纵向涡旋，该涡旋将主流流场边界层外的高能流体卷入到边界层内，增加了边界层内部的流动能量，从而延缓或抑制了流动分离。与相同条件下未采用涡旋射流控制的扩压器相比，其压力恢复系数增加19.8%，表明涡旋射流是一种有效的边界层分离控制方法。文中还分析了不同射流孔数和射流倾斜角对于压力恢复系数的影响，发现选择合适的涡旋射流孔数及其射流倾斜角等参数，可以更有效的控制扩压器内流动分离。 |
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关键词：
流动控制
涡旋射流
流动分离
大涡模拟
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Large-eddy Simulation for Control of Flow Separation in Conical Diffuser by Vortex Generator Jets |
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FAN Tao XIE Yong-hui ZHANG Di |
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Abstract:
To investigate the mechanism of active control of flow separation in conical diffuser by vortex generator jet (VGJ) method, the flow field in a 14° conical diffuser was analyzed based on large-eddy simulation (LES) method in this study. The numerical results show good agreement with experimental data. According to the flow charts at several sections, the formation of complex vortices is illuminated, and it is approved the strong vortices near jet holes come from shear-layer vortices. After break and dissipation, shear- layer vortices develop into unsymmetrical counter-rotating vortex pair at downstream and longitudinal vortices at far downstream of jet. The longitudinal vortices are generated in the boundary layer by shear stress and friction from jets. It increases cross-stream mixing of streamwise momentum and then suppresses or eliminates separation in conical diffuser. Compared with the diffuser without VGJs at the same condition, the pressure recovery coefficient is enhanced about 19.8%. The VGJ control strategy is demonstrated to be a usable technique for separation control. The effect of the number of jets and the pitch angle of jet on recovery coefficient of diffuser were analyzed, it is shown that the appropriate choice of parameters such as the number of jets and the pitch angle of jet can effectively control the flow separation in the diffuser. |
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Keywords:
flow control
vortex generator jets
flow separation
large-eddy simulation
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收稿日期 2008-05-08 修回日期 1900-01-01 网络版发布日期 |
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DOI: |
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基金项目:
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通讯作者: 谢永慧 |
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作者简介: |
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作者Email: yhxie@mail.xjtu.edu.cn |
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| Copyright by 中国电机工程学报 |
