一级半轴流涡轮非轴对称端壁的优化设计
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摘要
建立了一套适用于轴流涡轮非轴对称端壁的优化系统,该系统主要基于人工神经网络方法和遗传算法.为了降低高维优化设计的计算规模,采用了设计空间分区方法,结合D-最优试验设计方法建立计算样本数据库;使用人工神经网络方法建立代理模型,以等熵效率为优化目标函数,优化方法为遗传算法.采用上述优化策略对Aachen一级半涡轮进行优化设计,端壁布置了25个控制点,数据库样本规模为300,优化后等熵效率增加了0.43%.计算结果表明:采用空间分区方法在保持足够代理模型精度的同时,可以降低样本数据库的规模,并且在试验设计方法选择时带来更多的灵活性.另外,非轴对称端壁造型在静叶上的应用效果相较于动叶要好,且在第二级静叶的应用效果最佳.
An optimization design method based on genetic algorithms and artificial neural networks(ANN)is developed to improve the performance of non-axisymmetric endwall profiling,which has been proved to be an effective method to control the secondary flows and improve flow structures of turbomachinery.For a 1.5-stage axial turbine,aparameterized model of non-axisymmetric endwall with 25 control points on the hub is established,the surrogate model is built using subspace strategy,D-optimal experimental design method and ANN model with a database of 300 samples.The isentropic efficiency is selected as optimal objective,and genetic algorithms is chosen as the optimization algorithm.The total-to-total isentropic efficiency of the turbine increase about 0.43%after optimization.The results show that the subspace strategy used to build the database brings more flexibility and indicated that the non-axisymmetric endwall contouring has a significant influence on stators than rotors.
An optimization design method based on genetic algorithms and artificial neural networks(ANN)is developed to improve the performance of non-axisymmetric endwall profiling,which has been proved to be an effective method to control the secondary flows and improve flow structures of turbomachinery.For a 1.5-stage axial turbine,aparameterized model of non-axisymmetric endwall with 25 control points on the hub is established,the surrogate model is built using subspace strategy,D-optimal experimental design method and ANN model with a database of 300 samples.The isentropic efficiency is selected as optimal objective,and genetic algorithms is chosen as the optimization algorithm.The total-to-total isentropic efficiency of the turbine increase about 0.43%after optimization.The results show that the subspace strategy used to build the database brings more flexibility and indicated that the non-axisymmetric endwall contouring has a significant influence on stators than rotors.
引文
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[11]高增珣,高学林,袁新.透平叶栅非轴对称端壁的气动最优化设计[J].工程热物理学报,2007,28(4):589-591.
[12]张鹏,刘波,曹志远,等.对转压气机非轴对称端壁造型优化设计[J].航空动力学报,2014,29(11):2570-2578.
[13]唐慧敏,刘帅强,罗华玲.涡轮平面叶栅非轴对称端壁优化设计[J].航空动力学报,2015,30(3):707-713.
[14]李恩颖.近似模型优化体系关键技术研究及应用[D].长沙:湖南大学,2009.
[15] GALLUS H E,WALRAEVENS R E.Stator-rotor-stator interaction in an axial flow turbine and its influence on loss mechanism[C]∥AGARD Conference Proceedings of Propulsion and Energetics Panel(PEP)85th Symposium.Derby,UK:AGARD,1995:AGARD-CP-571.
[16] JAMESON A,SCHMIDT W,TURKEL E.Numerical solution of the Euler equations by finite volume methods using Runge-Kutta time stepping schemes[C]∥14th AIAA Fluid and Plasma Dynamics Conference.Palo Alto,California,USA:AIAA,1981:AIAA paper 1981-1259.
[17] SPALART P,ALLMARAS S.A one-equation turbulence model for aerodynamic flows[J].La Recherche Aérospatiale,1992,439(1):5-21.
[2] GREGORY-SMITH D G,INGRAM G,JAYARAMAN P,et al.Non-axisymmetric turbine endwall profiling[J].Proceedings of the Institution of Mechanical Engineers,Part A:Journal of Power and Energy,2001,215(6):721-734.
[3] INGRAM G L,Endwall profiling for the reduction of secondary flow in turbines[D].Durham,UK:Durham University,2003.
[4] HARVEY N W,BRENNAN G,NEWMAN D A,et al.Improving turbine efficiency using nonaxisymmetric end walls:Validation in the multi-row environment and with low aspect ratio blading[C]∥ASME Turbo Expo 2002:Power for Land,Sea,and Air.Amsterdam,Netherlands:American Society of Mechanical Engineers,2002:ASME Turbo Expo 2002-GT-30337.
[5] ROSE M G.Non-axisymmetric endwall profiling in HP NGV’s of an axial flow gas turbine[C]∥ASME International Gas Turbine and Aeroengine Congress and Exposition.Hague,Netherlands:American Society of Mechanical Engineers,1994:ASME Turbo Expo 94-GT-249.
[6] BRENNAN G,HARVEY N W,ROSE M G,et al.Improving the efficiency of the Trent 500HP turbine using non-axisymmetric end walls:PartⅠ—turbine design[C]∥ASME Turbo Expo 2001:Power for Land,Sea,and Air.New Orleans,Louisiana,USA:American Society of Mechanical Engineers,2001:ASME Turbo Expo 2001-GT-0444.
[7] ROSE M G,HARVEY N W,SEAMAN P,et al.Improving the efficiency of the Trent 500HP turbine using non-axisymmetric end walls:PartⅡ—experimental validation[C]∥ASME Turbo Expo 2001:Power for Land,Sea,and Air.New Orleans,Louisiana,USA:American Society of Mechanical Engineers,2001:ASME Turbo Expo 2001-GT-0505.
[8] POEHLER T,NIEWOEHNER J,JESCHKE P,et al.Investigation of non-axisymmetric endwall contouring and 3Dairfoil design in a 1.5stage axial turbine:PartⅠ—design and novel numerical analysis method[C]∥ASME Turbo Expo 2014:Turbine Technical Conference and Exposition.Düsseldorf,Germany:American Society of Mechanical Engineers,2014:ASME Turbo Expo GT-2014-26784.
[9] SNEDDEN G C,The application of non-axisymmetric endwall contouring in a 1-1/2stage,rotating turbine[D].Durham,UK:Durham University,2011.
[10]李国君,马晓永,李军.非轴对称端壁成型及其对叶栅损失影响的数值研究[J].西安交通大学学报,2005,39(11):1169-1172.
[11]高增珣,高学林,袁新.透平叶栅非轴对称端壁的气动最优化设计[J].工程热物理学报,2007,28(4):589-591.
[12]张鹏,刘波,曹志远,等.对转压气机非轴对称端壁造型优化设计[J].航空动力学报,2014,29(11):2570-2578.
[13]唐慧敏,刘帅强,罗华玲.涡轮平面叶栅非轴对称端壁优化设计[J].航空动力学报,2015,30(3):707-713.
[14]李恩颖.近似模型优化体系关键技术研究及应用[D].长沙:湖南大学,2009.
[15] GALLUS H E,WALRAEVENS R E.Stator-rotor-stator interaction in an axial flow turbine and its influence on loss mechanism[C]∥AGARD Conference Proceedings of Propulsion and Energetics Panel(PEP)85th Symposium.Derby,UK:AGARD,1995:AGARD-CP-571.
[16] JAMESON A,SCHMIDT W,TURKEL E.Numerical solution of the Euler equations by finite volume methods using Runge-Kutta time stepping schemes[C]∥14th AIAA Fluid and Plasma Dynamics Conference.Palo Alto,California,USA:AIAA,1981:AIAA paper 1981-1259.
[17] SPALART P,ALLMARAS S.A one-equation turbulence model for aerodynamic flows[J].La Recherche Aérospatiale,1992,439(1):5-21.