燃气涡轮篦齿叶顶流动传热特性的数值研究

Numerical Investigations on the Flow and Heat Transfer Characteristics of Gas Turbine Blade Tip with Labyrinth Seals

以GE-E3型第一级叶栅为研究对象开展数值研究,基于高压涡轮常规凹槽叶顶提出新型叶顶结构。通过求解三维Reynolds-Averaged Navier-Stokes(RANS)和标准k-ω湍流模型研究了篦齿结构和布局对叶顶流动传热特性的影响。数值预测的平叶顶的流场分布与实验数据吻合良好,验证了数值方法的可靠性。研究结果表明:篦齿叶顶可以有效降低中弦处的叶顶泄漏损失,篦齿形状对泄漏强度影响较小。此外,篦齿叶顶显著降低叶顶平均传热系数和热负荷,相比常规凹槽叶顶,前缘斜篦齿叶顶的平均传热系数降低了22.39%。在研究的新型叶顶结构中,倒梯形篦齿叶顶(I-TIP)具有最低的叶顶平均传热系数,梯形篦齿叶顶(T-TIP)具有最低的叶顶热流量,前缘斜篦齿叶顶具有最佳的气热性能。在叶顶凹槽前缘布置篦齿结构可有效降低叶顶换热系数。

The present research focus on the first stage turbine blade of GE-E3,and new blade tip structures were proposed based on the conventional squealer tip of high pressure turbines.By solving three-dimensional Reynolds-Averaged Navier-Stokes(RANS)and standard k-ωturbulent model,the present research studies the influence of the structure and layout of the labyrinth seals on the flow and heat transfer characteristics of the turbine blade.The numerical results agree well with the experimental data on the experimental blade tip.The accuracy of the utilized numerical approach has been validated.The numerical results show that the blade tip with labyrinth seals can effectively reduce the leakage flow intensity at the middle chord of the blade while the shape of labyrinth seals has little effect on the leakage intensity.In addition,the blade tip with labyrinth seals can effectively reduce the average heat transfer coefficient and heat flux at the tip of blade.Compared with the conventional squealer tip,the average heat transfer coefficient at the blade tip with inclined labyrinth seals at leading edge is reduced by 22.39%.Among the layouts,the blade tip with inverted trapezoidal labyrinth seals has the lowest average tip heat transfer coefficient and the blade tip with trapezoidal labyrinth seals has the lowest heat flux.The labyrinth seals at the leading edge of the blade tip can effectively reduce the heat transfer coefficient at the blade tip.