燃气透平叶型气动与传热的优化设计

Aero-thermal optimization of gas turbine blade airfoil

建立了一个透平叶型气动与传热优化的两步模型.第1步采用解析多项式曲线构造叶片的参数化造型,基于CFD数值模拟,通过正交设计和敏感性分析,优选几何设计参数.第2步采用贝塞尔(Bezier)曲线参数化叶型型线,以总压损失和表面热流加权函数为优化目标,调整叶型型线,获得了气动性能与热负荷较优的叶型.设计案例的结果表明:增加安装角可以降低叶片压力面热负荷;增大叶片前缘直径可以降低前缘滞止点热负荷.调整叶型的表面曲率分布,有可能推迟吸力面的转捩,弱化叶片表面的传热.两步优化法计算量小,收敛性好,具有工程应用价值.

A two-step optimization method was presented to improve the aero-thermal characteristics of turbine blade airfoil. The first step was to construct turbine airfoil by polynomial lines. Design parameters were screened by design of experiment （DOE） and factorized sensitive analysis for best performance obtained from CFD simulations. The second step was to optimize airfoil, which was parameterized in Bezier lines for minimum flow loss and surface heat transfer in a weighted objective function. Result of design sample shows that increased stagger angle leads to lowered heat transfer along the pressure side surface, and larger leading edge radius reduces the local heat transfer around stagnation point. Reforming the polynomial shaped airfoil provides possible delay of the transition on the blade suction side surface and reduces whole heat transfer rate. Two-step method has relatively low computation requirement and good convergence, which is valuable for engineering purposes.