In recent years, the hollow fan blades have been widely used to meet the demand for light weight and good performance of the aero-engine. However, the relationship between the hollow structure and the aeroelastic stab...In recent years, the hollow fan blades have been widely used to meet the demand for light weight and good performance of the aero-engine. However, the relationship between the hollow structure and the aeroelastic stability has not been studied yet in the open literature. In this paper,it has been investigated for an H-shaped hollow fan blade. Before studying the flutter behavior, the methods of parametric modeling and auto-generation of Finite Element Model(FEM) are presented. The influence of the feature parameters on the vibration frequency and mode shape(as the input of flutter calculation) of the first three modes are analyzed by the Orthogonal Experimental Design(OED) method. The results show that the parameters have a more remarkable impact on the first torsional mode and thus it is concerned in the flutter sensitivity analysis. Compared with the solid blade, the minimum aerodynamic damping of the hollow blade decreases, indicating that the hollow structure makes the aeroelastic stability worse. For the parameters describing the hollow section, the rib number N has the greatest influence on the minimum aerodynamic damping, followed by the wall thickness W5. For the parameters in the height of hollow segment, the aerodynamic damping increases with the increase of parameters M1 and M2. This means that reducing the height of the hollow segment is helpful to improve the aeroelastic stability. Compared with the impact of parameters in hollow section, the variation of aerodynamic damping caused by the height of the hollow segment is small.展开更多
To reduce the influence of adverse flow conditions at the fan hub and improve fan aerodynamic performance, a modification of conventional axial fan blades with numerical and experimental investigation is presented. Ho...To reduce the influence of adverse flow conditions at the fan hub and improve fan aerodynamic performance, a modification of conventional axial fan blades with numerical and experimental investigation is presented. Hollow blade root is manufactured near the hub. The numerical and experimental results show that hollow blade root has some effect on the static performance. Static pressure of the modified fan is generally the same with that of the datum fan, while, the efficiency curve of the modified fan has a different trend with that of the datum fan. The highest efficiency of the modified fan is 10% greater than that of the datum fan. The orthogonal experimental re- suits of fan noise show that hollow blade root is a feasible method of reducing fan noise, and the maximum value of noise reduction is about 2 dB. The factors affecting the noise reduction of hollow blade root are in the order of importance as follows： hollow blade margin, hollow blade height and hollow blade width. The much smoother pressure distribution of the modified fan than that of the datum fan is the main mechanism of noise reduction of hollow blade root. The research results will provide the proof of the parameter optimization and the structure de- sign for high performance and low noise small axial fans.展开更多
Several structural design parameters for the description of the geometric features of a hollow fan blade were determined.A structural design optimization model of a hollow fan blade which based on the strength constra...Several structural design parameters for the description of the geometric features of a hollow fan blade were determined.A structural design optimization model of a hollow fan blade which based on the strength constraint and minimum mass was established based on the finite element method through these parameters.Then,the sequential quadratic programming algorithm was employed to search the optimal solutions.Several groups of value for initial design variables were chosen,for the purpose of not only finding much more local optimal results but also analyzing which discipline that the variables according to could be benefit for the convergence and robustness.Response surface method and Monte Carlo simulations were used to analyze whether the objective function and constraint function are sensitive to the variation of variables or not.Then the robust results could be found among a group of different local optimal solutions.展开更多
针对桁架式内腔空心风扇叶片,运用UG二次开发工具UG/Open API,NX Open C++及C++编程语言混合开发方法,在UG环境中,建立空心叶片参数化三维模型和参数化有限元模型,在叶片有限元网格形式不变的前提下,快速生成叶片有限元模型,有效解决优...针对桁架式内腔空心风扇叶片,运用UG二次开发工具UG/Open API,NX Open C++及C++编程语言混合开发方法,在UG环境中,建立空心叶片参数化三维模型和参数化有限元模型,在叶片有限元网格形式不变的前提下,快速生成叶片有限元模型,有效解决优化过程中网格自动更新问题。在此基础上,自动施加边界条件和载荷,从而实现集造型、分网、分析为一体的自动化设计。实例表明,宽弦空心风扇叶片参数化设计平台不仅可以快速完成空心叶片参数化设计及强度分析,也可为后续开展叶片结构优化奠定基础。展开更多
基金co-supported by the National Science and Technology Major Project,China(No.2017-Ⅳ-0002-0039)the National Natural Science Foundation of China(No.51475022)。
文摘In recent years, the hollow fan blades have been widely used to meet the demand for light weight and good performance of the aero-engine. However, the relationship between the hollow structure and the aeroelastic stability has not been studied yet in the open literature. In this paper,it has been investigated for an H-shaped hollow fan blade. Before studying the flutter behavior, the methods of parametric modeling and auto-generation of Finite Element Model(FEM) are presented. The influence of the feature parameters on the vibration frequency and mode shape(as the input of flutter calculation) of the first three modes are analyzed by the Orthogonal Experimental Design(OED) method. The results show that the parameters have a more remarkable impact on the first torsional mode and thus it is concerned in the flutter sensitivity analysis. Compared with the solid blade, the minimum aerodynamic damping of the hollow blade decreases, indicating that the hollow structure makes the aeroelastic stability worse. For the parameters describing the hollow section, the rib number N has the greatest influence on the minimum aerodynamic damping, followed by the wall thickness W5. For the parameters in the height of hollow segment, the aerodynamic damping increases with the increase of parameters M1 and M2. This means that reducing the height of the hollow segment is helpful to improve the aeroelastic stability. Compared with the impact of parameters in hollow section, the variation of aerodynamic damping caused by the height of the hollow segment is small.
基金supported by National Natural Science Foundation of China(No.51249003,No.51006090)Major Special Project of Technology Office in Zhejiang Province(No.2011C16038,No.2011C11073)
文摘To reduce the influence of adverse flow conditions at the fan hub and improve fan aerodynamic performance, a modification of conventional axial fan blades with numerical and experimental investigation is presented. Hollow blade root is manufactured near the hub. The numerical and experimental results show that hollow blade root has some effect on the static performance. Static pressure of the modified fan is generally the same with that of the datum fan, while, the efficiency curve of the modified fan has a different trend with that of the datum fan. The highest efficiency of the modified fan is 10% greater than that of the datum fan. The orthogonal experimental re- suits of fan noise show that hollow blade root is a feasible method of reducing fan noise, and the maximum value of noise reduction is about 2 dB. The factors affecting the noise reduction of hollow blade root are in the order of importance as follows： hollow blade margin, hollow blade height and hollow blade width. The much smoother pressure distribution of the modified fan than that of the datum fan is the main mechanism of noise reduction of hollow blade root. The research results will provide the proof of the parameter optimization and the structure de- sign for high performance and low noise small axial fans.
文摘Several structural design parameters for the description of the geometric features of a hollow fan blade were determined.A structural design optimization model of a hollow fan blade which based on the strength constraint and minimum mass was established based on the finite element method through these parameters.Then,the sequential quadratic programming algorithm was employed to search the optimal solutions.Several groups of value for initial design variables were chosen,for the purpose of not only finding much more local optimal results but also analyzing which discipline that the variables according to could be benefit for the convergence and robustness.Response surface method and Monte Carlo simulations were used to analyze whether the objective function and constraint function are sensitive to the variation of variables or not.Then the robust results could be found among a group of different local optimal solutions.
文摘针对桁架式内腔空心风扇叶片,运用UG二次开发工具UG/Open API,NX Open C++及C++编程语言混合开发方法,在UG环境中,建立空心叶片参数化三维模型和参数化有限元模型,在叶片有限元网格形式不变的前提下,快速生成叶片有限元模型,有效解决优化过程中网格自动更新问题。在此基础上,自动施加边界条件和载荷,从而实现集造型、分网、分析为一体的自动化设计。实例表明,宽弦空心风扇叶片参数化设计平台不仅可以快速完成空心叶片参数化设计及强度分析,也可为后续开展叶片结构优化奠定基础。
