Abstract The present numerical investigation of Leading Edge (LE) Nozzle Guide Vane (NGV) is considered with five rows of impingement holes combined with five rows of film cooled for the secondary coolant flow path analysis. The coolant mass flow rate variations in all the LE rows of the film holes externally subjected to the hot main stream were obtained by making a three-dimensional computational analysis of NGV with a staggered array of film cooled rows. The experiments were carried out for the same NGV using Particle Image Velocimetry technique to determine the effused coolant jet exit velocity at the stagnation row of film holes as mentioned in reference [Kukutla PR, Prasad BVSSS. Secondary flow visualization on stagnation row of a combined impingement and film cooled high pressure gas turbine nozzle guide vane using PIV technique, J Visualization, 2017; DOI: 10.1007/s12650-017-0434-6]. In this paper, results are presented for three different mass flow rates ranges from 0.0037 kg/s to 0.0075 kg/s supplied at the Front Impingement Tube (FIT) plenum. And the mainstream velocity 6 m/s was maintained for all the three coolant mass flow rates. The secondary coolant flow distribution was performed from SH1 to SH5 row of film holes. Each row of a showerhead film hole exit coolant mass flow rate varied in proportion to the amount of coolant mass rates supplied at the FIT cooling channel. The corresponding minimum and maximum values and their film hole locations were altered. The same behaviour was continued for the coolant pressure drop and temperature rise from SH1 to SH5 row of film holes. Owing to the interaction between hot main stream and the coolant that effuses out of the film holes, occasional presence of hot gas ingestion was noticed for certain flow rates. This caused nonlinear distribution in mass flow, pressure drop and temperature rise. The minimum flow rate results estimate oxidation of NGV material near the film cooled hole. And the effect of hot gas ingestion on the ejected film cooled jet which would recommends effective oxidation resistant material which in turn leads to better durability of the NGV surface.

中文翻译：

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高压燃气轮机喷嘴导叶第一级冲击膜冷复合膜孔二次风性能数值研究

摘要 目前对前沿 (LE) 喷嘴导向叶片 (NGV) 的数值研究考虑了五排冲击孔和五排薄膜冷却，用于二次冷却剂流路分析。通过对具有交错排列的薄膜冷却行的 NGV 进行三维计算分析，获得了外部受到热主流的薄膜孔的所有 LE 行的冷却剂质量流量变化。使用粒子图像测速技术对同一 NGV 进行了实验，以确定参考文献 [Kukutla PR，Prasad BVSSS. 使用 PIV 技术对组合冲击和薄膜冷却高压燃气轮机喷嘴导叶的滞流排进行二次流动可视化，J 可视化，2017 年；DOI：10.1007/s12650-017-0434-6]。在本文中，给出了在前冲击管 (FIT) 增压室提供的三种不同质量流速范围（从 0.0037 kg/s 到 0.0075 kg/s）的结果。对于所有三种冷却剂质量流量，主流速度都保持在 6 m/s。从 SH1 到 SH5 排薄膜孔进行二次冷却剂流量分配。每排喷头薄膜孔出口冷却剂质量流量与在 FIT 冷却通道处供应的冷却剂质量流量成比例地变化。相应的最小值和最大值及其膜孔位置已更改。对于从 SH1 到 SH5 排薄膜孔的冷却剂压降和温度升高，继续相同的行为。由于热主流和从薄膜孔中流出的冷却剂之间的相互作用，在某些流速下偶尔会出现热气体吸入。这导致质量流量、压降和温升的非线性分布。最小流速结果估计了薄膜冷却孔附近 NGV 材料的氧化。以及热气吸入对喷射薄膜冷却射流的影响，这将推荐有效的抗氧化材料，从而使 NGV 表面具有更好的耐久性。