Abstract Intersecting cooling holes allow very high density heat exchangers to be implemented in the cooling systems of gas turbine blades. The pressure loss and heat transfer characteristics caused by the highly turbulent flow at intersections are poorly understood. These are characterised experimentally and numerically for a single intersection of two equal diameter holes at 90 ∘ or 60 ∘ /120 ∘ angles of intersection, 0%, 10%, 49% and 88% offset. Large variations in pressure loss occur for a given intersection geometry; dependent on the mass flow splits, and the level of offset. Pressure losses range from 4 to more than 30 inlet dynamic heads. This allows the flow distribution in an engine application to be tuned, allowing for manufacturing uncertainties. Heat transfer coefficient (HTC) distributions measured in single intersections are reported. These show clear enhancement associated with stripping the fluid boundary layer and mixing of the bulk flow. High local heat transfer gradients were observed at the intersections and circumferentially averaged Nusselt number enhancement of up to 5 found where the degree of pipe intersection is significant. The HTC distributions allow the required packing of hole intersections while controlling the pressure margin. The experimental data are replicated in CFD studies which show good agreement within experimental uncertainty. Thus more detailed numerical models can be relied on for a full range of intersection angles and offsets. Extending the modelling to include multiple linked intersections confirmed that data measured in single intersections are applicable to a matrix of multiply intersecting holes.

中文翻译：

---

交叉孔换热器的压力损失和传热特性

摘要 交叉冷却孔允许在燃气轮机叶片的冷却系统中实施非常高密度的热交换器。由交叉口处的高湍流引起的压力损失和传热特性知之甚少。对于 90 ∘ 或 60 ∘ /120 ∘ 交叉角、0%、10%、49% 和 88% 偏移的两个相同直径孔的单个交叉点，这些是通过实验和数值表征的。对于给定的交叉几何形状，压力损失会发生很大变化；取决于质量流量分流和偏移水平。压力损失范围从 4 到 30 多个入口动态压头。这允许调整发动机应用中的流量分布，从而允许制造不确定性。报告了在单个交叉点中测量的传热系数 (HTC) 分布。这些显示与剥离流体边界层和大量流动的混合相关的明显增强。在交叉处观察到高局部传热梯度，在管道交叉程度显着的地方发现周向平均努塞尔数增强高达 5。HTC 分布允许在控制压力裕度的同时对孔交叉点进行所需的填充。实验数据在 CFD 研究中复制，在实验不确定性内显示出良好的一致性。因此，对于全范围的相交角度和偏移量，可以依赖更详细的数值模型。扩展建模以包括多个链接的交叉点，确认在单个交叉点中测量的数据适用于多个交叉孔的矩阵。