高温高压工况下NASA C3X涡轮叶片旋流冷却和冲击冷却的性能对比研究

Comparative Study on Swirl cooling and Impingement Cooling Performance for NASA C3X Vane under High Parameter Conditions

文中建立了NASA C3X叶片前缘旋流冷却和冲击冷却结构,在高温高压工况下对旋流冷却和冲击冷却流动和传热特性进行了比较分析.考虑了10000、30000、50000、70000和90000五个进气腔室入口雷诺数.结果表明,与低参数条件相比,较高的冷气压力导致冷气速度较低,但仍具有较高的传热强度.旋流冷却喷嘴下方C3X叶片靶面弧度较高,冷气流经时产生较高的向心力,冷气压力升高.随后冷气流经旋流腔室底部低弧度靶面,压力降低,流速升高,换热增强.旋流冷却产生带状高努塞尔数区域,并沿着下游方向均匀分布.冲击冷却在射流撞击位置产生椭圆状高努塞尔数区域,并且受到横流的作用沿着下游方向传热强度逐渐降低.在高温高压工况下,旋流冷却整体的平均传热强度较高,但由于对靶面冲刷的作用较强流动阻力较高.旋流冷却的综合传热因子高于冲击冷却,并且在高参数下随着雷诺数的升高,旋流冷却的优势更加明显.

This paper establishes the structure of NASA C3X blade leading edge swirl and impingement cooling.The swirl and impingement cooling flow and heat transfer characteristics are compared and analyzed under high temperature and high pressure conditions.The coolant chamber inlet Reynolds numbers of 10000,30000,50000,70000 and 90000 are considered.The results show that compared with low parameter conditions,higher coolant pressure results in lower coolant velocity,but it still has a higher heat transfer intensity.The target wall curvature under the swirl cooling nozzle is relatively high,the coolant flow generates the higher centripetal force,and the coolant pressure increases.Then,the coolant flows through the low curvature target wall at the swirl chamber bottom,the pressure decreases,the velocity increases,and the heat exchange enhances.Swirl cooling produces a band-shaped high Nusselt number area,which is evenly distributed along the downstream direction.Impingement cooling produces an elliptical high Nusselt number area at the jet impact position,and the Nusselt number gradually decreases along the downstream direction due to the cross flow.Under high temperature and high pressure conditions,the overall average Nusselt number of swirl cooling is higher,but the flow resistance is also higher due to the stronger flushing effect on the target wall.The comprehensive heat transfer factor of swirl cooling is higher than that of impingement cooling,and with the increase of Reynolds number,the swirl cooling advantages become more obvious under high parameter.