Direct numerical simulation of a tip-leakage flow in a planar duct with a longitudinal slit
Direct numerical simulation of a tip-leakage flow in a planar duct with a longitudinal slit
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DOI：
10.1063/1.5124163
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发表时间：
2019-12
影响因子：
4.6
通讯作者：
J. Fang;Yanfei Gao;Yangwei Liu;Lipeng Lu;Yufeng Yao;C. Le Ribault
中科院分区：
文献类型：
--
作者：
J. Fang;Yanfei Gao;Yangwei Liu;Lipeng Lu;Yufeng Yao;C. Le Ribault
本文采用直接数值模拟的方法，研究了靠近上壁面的纵向狭缝注入横向流的平面管道流动形态，探讨了与涡轮机械中最重要的流动现象之一的叶尖泄漏涡（TLV）相关的潜在流动机理。在当前流动模型中识别了涡轮机械转子TLV的主要特性。对平均流场和瞬时流场的分析表明，主（轴）流和射流（横）流的相互作用是产生TLV的主要来源。然后研究了TLV的演变，并确定了涡旋破裂现象。TLV的演化可分为三个阶段，即形成阶段、破裂阶段和扩散阶段。分析了平均流线和湍流动能（TKE）预算，表明形成阶段的高TKE中心点是高旋流涡丝和平均速度梯度相互作用的结果。在TLV外部，TKE主要在剪切层产生，并通过湍流输送向中心输送。本文采用直接数值模拟的方法，研究了靠近上壁面的纵向狭缝注入横向流的平面管道流动形态，探讨了与涡轮机械中最重要的流动现象之一的叶尖泄漏涡（TLV）相关的潜在流动机理。在当前流动模型中识别了涡轮机械转子TLV的主要特性。对平均流场和瞬时流场的分析表明，主（轴）流和射流（横）流的相互作用是产生TLV的主要来源。然后研究了TLV的演变，并确定了涡旋破裂现象。TLV的演化可分为三个阶段，即形成阶段、破裂阶段和扩散阶段。对平均流线和湍流动能（TKE）收支进行了分析，结果表明，地层阶段的高TKE中心点是由高湍流和低湍流相互作用造成的。
A planar duct flow configuration with a cross-flow injected from a longitudinal slit close to the upper wall of the duct is studied by using a direct numerical simulation approach to explore the underlying flow mechanism in relation to the tip-leakage vortex (TLV), which is one of the most important flow phenomena in turbomachinery. Major characteristics of TLV in a rotor of turbomachinery are identified in the current flow model. The analysis of mean and instantaneous flow fields reveals that the interaction between the main (axial) flow and jet (cross) flow is the primary source of the generation of the TLV. The evolution of the TLV is then investigated, and a vortex breakup phenomenon is identified. The evolution of TLV can be divided into three phases, i.e., the formation phase, the breakup phase, and the diffusion phase. Mean streamlines and turbulence kinetic energy (TKE) budgets are analyzed, showing that the high TKE central spot in the formation phase is due to the interaction between highly swirling vortex filaments and mean velocity gradient. In the outer part of the TLV, the TKE is mainly produced in the shear-layer and transported toward the center by the turbulence transport.A planar duct flow configuration with a cross-flow injected from a longitudinal slit close to the upper wall of the duct is studied by using a direct numerical simulation approach to explore the underlying flow mechanism in relation to the tip-leakage vortex (TLV), which is one of the most important flow phenomena in turbomachinery. Major characteristics of TLV in a rotor of turbomachinery are identified in the current flow model. The analysis of mean and instantaneous flow fields reveals that the interaction between the main (axial) flow and jet (cross) flow is the primary source of the generation of the TLV. The evolution of the TLV is then investigated, and a vortex breakup phenomenon is identified. The evolution of TLV can be divided into three phases, i.e., the formation phase, the breakup phase, and the diffusion phase. Mean streamlines and turbulence kinetic energy (TKE) budgets are analyzed, showing that the high TKE central spot in the formation phase is due to the interaction between highly swir...