Effects of Endwall Boundary Layer Thickness and Blade Tip Geometry on Flow Through High Pressure Turbine Passages
Effects of Endwall Boundary Layer Thickness and Blade Tip Geometry on Flow Through High Pressure Turbine Passages
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端壁边界层厚度和叶尖几何形状对高压涡轮通道流动的影响
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
R. Volino
中科院分区：
文献类型：
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作者：
R. Volino
实验是在一个端壁叶顶间隙可调的直线高压涡轮机叶栅中进行的。该叶栅包括一个尾流发生器，该尾流发生器带有模拟上游叶片排效应的移动杆。记录的病例没有头端间隙，间隙为轴向弦的1.5%，间隙为弦的3.8%。平叶尖的情况被认为是厚和薄的端壁边界层。扁平尖端和凹槽尖端的病例记录了薄端壁边界层。对于所有的情况下，数据采集有和没有上游尾流。记录包括端壁区域的总压损失场和使用粒子图像测速仪（PIV）获得的相应速度场。PIV测量显示了流场中的各种旋涡及其对非定常尾迹的响应。旋涡的强度和位置与高总压损失区域直接相关。减小端壁边界层厚度有助于减少损失，但也会导致泄漏流增加，从而增加损失，特别是在叶尖间隙较大的情况下。与平叶顶情况相比，凹槽叶顶减少了损失。© 2014 ASME
Experiments were conducted in a linear high pressure turbine cascade with an adjustable tip gap at one endwall. The cascade included a wake generator with moving rods that simulated the effect of an upstream vane row. Cases were documented with no tip gap, a gap of 1.5% of axial chord, and a gap of 3.8% of chord. Cases with flat blade tips were considered with thick and thin endwall boundary layers. Cases with flat tips and squealer tips were documented with the thin endwall boundary layer. For all cases data were acquired both with and without upstream wakes. Documentation included total pressure loss fields in the endwall region and corresponding velocity fields acquired using particle image velocimetry (PIV). The PIV measurements showed the various vortices in the flow field and their response to unsteady wakes. The strength and position of the vortices were directly related to regions of high total pressure loss. Reducing the endwall boundary layer thickness tended to reduce losses, but also resulted in increased leakage flow, which increased losses, particularly in cases with a large tip gap. The squealer tip reduced losses compared to the flat tip cases.© 2014 ASME