Abstract A new geometry parametric method of winglet-cavity tip has been introduced in the optimization procedure based on three-dimensional steady CFD numerical calculation and analysis. Firstly, the reliability of numerical method and grid independency are studied. Then an aerodynamic optimization is performed in an unshrouded axial high pressure turbine with winglet-cavity tip. The optimum winglet-cavity tip has higher turbine stage efficiency and smaller tip leakage mass flow rate than the cavity tip and flat tip. Compared with the results of cavity tip, the effects of the optimum winglet-cavity tip indicate that the stage efficiency is improved effectively by 0.41% with less reduction of tip leakage mass flow rate. The variation of turbine stage efficiency with tip gap states that the optimum winglet-cavity tip obtains the smallest efficiency change rate ∆η/(∆τ/H). For the optimum winglet-cavity tip, the endwall flow and blade tip leakage flow pattern are used to analysis the physical mechanical of losses. In addition, the effects of pressure-side winglet and suction-side winglet are analyzed respectively by the deformation of the optimum winglet-cavity tip. The numerical results show that the pressure-side winglet reduces the tip leakage flow effectively, and the suction-side winglet shows a great improvement on the turbine stage efficiency.

中文翻译：

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轴向高压涡轮级小翼腔尖端的气动优化

摘要 基于三维稳态CFD数值计算和分析，在优化过程中引入了一种新的小翼腔尖端几何参数化方法。首先研究了数值方法的可靠性和网格独立性。然后在具有小翼腔尖端的无护罩轴向高压涡轮机中进行空气动力学优化。优化的小翼腔尖端比腔尖端和平尖端具有更高的涡轮级效率和更小的尖端泄漏质量流量。与腔尖结果相比，优化小翼腔尖的效果表明，级效率有效提高了0.41%，而尖端泄漏质量流量降低较少。涡轮级效率随叶尖间隙的变化表明，最佳小翼腔叶尖获得最小的效率变化率 Δη/(Δτ/H)。对于最佳的小翼腔尖端，端壁流和叶片尖端泄漏流型用于分析损失的物理力学。此外，通过优化小翼腔尖端的变形，分别分析了压力侧小翼和吸力侧小翼的影响。数值结果表明，压力侧小翼有效地减少了叶尖泄漏流，吸力侧小翼对涡轮级效率有很大的提高。通过优化小翼腔尖端的变形，分别分析了压力侧小翼和吸力侧小翼的影响。数值结果表明，压力侧小翼有效地减少了叶尖泄漏流，吸力侧小翼对涡轮级效率有很大的提高。通过优化小翼腔尖端的变形，分别分析了压力侧小翼和吸力侧小翼的影响。数值结果表明，压力侧小翼有效地减少了叶尖泄漏流，吸力侧小翼对涡轮级效率有很大的提高。