非轴对称端壁气膜冷却透平级内流动传热机理的研究

The aerodynamic performance, cooling effectiveness and heat transfer characteristic in the high temperature gas turbine stage can be effectively enhanced by the advanced film cooling arrangement on the non-axisymmetric endwall. In the present study, experimental tests, numerical simulations and multi-objective optimizations are performed to investigate the flow and unsteady conjugate heat transfer characteristics in the turbine stage with film cooling holes on the non-axisymmetric endwall. To analyze the flow and heat transfer performance in the turbine stage with film cooling holes on the non-axisymmetric endwall, a 3D steady and unsteady conjugate heat transfer computational methods are developed and the accuracy and reliability of the presented numerical methods are validated by the experimental measurements. The effects of unsteady wake flow, as well as the conjugate effect between the flow and solid domains, on the aerodynamic and heat transfer performance of the turbine stage with film cooling and non-axisymmetric endwall contouring are also investigated. Moreover, the influence of the matching regulation between non-axisymmetric endwall contouring and cooling hole arrangement on the mixing of coolant jet, secondary flow and main flow are analyzed. Additionally, the effect of rotor-stator interaction and conjugate heat transfer effects on cooling effectiveness and heat transfer coefficient distributions are obtained. And the statistic regulation of the effect of design variables of the film cooling turbine stage with non-axisymmetric endwall on the flow and heat transfer performance is also derived. Based on the above work, the influence of the matching regulation between non-axisymmetric endwall contouring and cooling hole arrangement on the flow, heat transfer and cooling effect in the turbine stage are revealed. The present study will be helpful for the design of advanced high temperature gas turbine endwall.

高性能的非轴对称端壁气膜冷却技术可以有效地提高高温燃气透平级内的气动效率和端壁区域的冷却传热性能。本项目拟采用实验测量、数值模拟和多目标优化设计相结合的方法对非轴对称端壁气膜冷却透平级内流动传热特性和非定常热流耦合传热机理开展详细的研究，发展非轴对称端壁气膜冷却透平级全三维热流耦合定常和非定常数值计算方法，并利用实验测量值进行考核，研究非定常尾迹和热流耦合作用对非轴对称端壁气膜冷却透平级气动传热性能的影响机制，分析非轴对称端壁造型和冷却孔结构间的匹配关系对端壁附近射流、二次流、主流间掺混发展和冷却传热性能的影响，阐明动静干涉和端壁固体导热效应对透平级内冷却效率和传热系数分布的影响机制，获得非轴对称端壁气膜冷却透平级几何设计参数对流动传热特性影响的概率统计规律，揭示非轴对称端壁气膜冷却结构匹配对透平级内流动、传热、冷却性能的热流耦合机理，为进一步提高高温燃气透平端壁的设计水平提供理论基础。

基于实验测量数据，开展了非轴对称端壁透平级内流动传热特性及影响机制的研究,得到了非轴对称端壁造型对透平叶栅内压力场、速度场影响，分析了非轴对称端壁造型对透平气动损失和传热性能的影响规律。发展了用于非轴对称端壁气膜冷却流动传热特性研究的数值求解方法，开展端壁造型与冷却孔结构间匹配关系对非轴对称端壁气膜冷却流动传热特性的影响研究，揭示了非轴对称端壁上冷却射流与二次流间相互作用对透平级气动、传热、冷却性能的作用机理。此外，为研究透平级内动叶顶部端壁的非轴对称结构，设计并分析了凹槽-小翼叶顶结构对于动叶顶部间隙流动传热特性的影响，研究了凹槽-小翼叶顶结构与叶顶气膜冷却射流和间隙泄漏流动之间的相互作用机制。独立开发了非轴对称端壁造型、射流孔槽参数化建模程序及多目标优化设计算法程序，建立了非轴对称端壁气膜冷却透平级内气动、传热、冷却性能的多目标优化设计方法和系统，优化结果通过实验测量和数值计算进行了验证。