An optimal design for axial-flow fan blade: theoretical and experimental studies

Cheng-Hung Huang,Chung-Wei Gau 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.2

The technique of inverse design problem (IDP) for optimizing the three-dimensional shape of an axial-flow fan blade based on the desired airflow rate is presented in this work. The desired volume flow rate of air can be obtained from the airflow rate of the existing axialflow fan by multiplying it with a constant which is greater than unity. The geometry of the redesigned fan blade is generated using numerous design variables, which enables the shape of the fan blade to be constructed completely; thus the technique of parameter estimation for the inverse design problem can be used in this study. Results show that with the redesigned optimal fan blade, the airflow rate of fan can be increased, thereby improving the performance of the axial-flow fan. Finally, to verify the validity of this work, the prototypes of the original and optimal axial-flow fan blades are fabricated and fan performance tests are conducted with these blades on the basis of the AMCA-210-99 standard. The algorithm used in the present study can be applied to the blade design problem in any propulsion and power systems.

HCF Weak Link Optimization for Wide-Chord Fan Blades Based on Circumferential Stacking Line Design

Yong Chen,Zhonglin Wang,Xiaopu Zhang 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.4

This paper describes the combination of a Kriging surrogate model with a micro-genetic algorithm for studying the influence of circumferential perturbations from the stack line on the high-cycle fatigue (HCF) weak link of a fan blade in a high-bypass-ratio turbofan engine. Based on the circumferential perturbations of the fan blade stack line, an automated system is developed for the parameterized modeling and meshing of the blade, and an integral platform is established for parameterized modeling, finite-element simulation, and optimization. The static stress, index of strain energy density, and vibratory stress margin of the 1st flex mode are set as the objective functions for the optimization of a fan blade. The results show that the optimized blade has three areas of low static stress, unlike the single “bull’s eye” distribution of the baseline blade. Optimization reduces the maximum static stress by 5.87% and the strain energy density index by 0.77%, while increasing the vibratory stress margin under the same dynamic load by 9.51%. The natural frequencies, mode shapes, resonance margins, and aerodynamic parameters exhibit no significant changes, which illustrates that the optimization method can improve the static stress and vibratory stress distribution of the fan blade without negatively influencing the other vibration and aerodynamic characteristics. The proposed method is an effective means of fan blade design optimization, and could be applied alongside other design variables and objective functions, such as the swept and skewed configuration of the stack line and twist angle of the blade, to optimize the vibration characteristics and aero-elastic performance.

The Optimal Blading Design and CFD Analysis of Axial Flow Fan

Chan Lee,Eui Jong Noh,Seung Wook Kim,Sang-Ho Yang 한국유체기계학회 2022 International journal of fluid machinery and syste Vol.15 No.3

This study proposes a method to optimize the blade angle and chord length distributions of axial flow fan rotor blade, and applied it to the design of the actual industrial axial flow fan. The present design model of the axial flow fan rotor blade is to construct and stack the section profiles using single circular arc and airfoil thickness distribution with the camber and stagger angles as design variables along the blade span height from hub to tip, and the chord length distribution is designed in a parabolic fashion from hub to tip. The performance and efficiency of the fan rotor blades are predicted by applying a through-flow analysis method to the 3D fan blade geometry obtained from the design variables of the camber angle, stagger angle, and chord length of the blade sections. These fan design and through-flow analysis methods are used as the simulation engine for optimization problem. Through applying the optimization algorithm, an optimal axial flow fan rotor is obtained with maximum efficiency and computational fluid dynamics analysis is performed to verify the result of the present optimal design. From the computational fluid dynamics calculation results, it can be seen that the present optimal design model has an efficiency improvement of about 2% compared to the initial design, and maintains relatively high efficiency even under partial load conditions.

A mass addition approach to the bypass turbomachine through flow inverse design problem

Peng Shan 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.10

In the design of a low bypass ratio fan stage, this paper links the through flow inverse design problems of the fan rotor, the core channel fan stator and the bypass channel fan stator together, as an organic whole, with the fan splitter aerodynamic design problem. It forms thus a unified through flow inverse problem for two-channel turbomachines. While an overall quasi-radial-equilibrium of the streamlines is iteratively achieved among five parts --- the fan rotor, the core channel fan stator, the bypass channel fan stator, the fan splitter and the position of the fan splitter, the blading processes for one fan blade, two fan vanes and one fan splitter ring are performed. This method designs in one pass a fan stage and a splitter with a precise bypass ratio. Its primary and key approach scheme is the introduction of a mass addition flow half way through the through flow streamline development. This scheme can serve as a new feature which can be inserted into those existing through flow programs. When subtracting a mass flow after adding a mass flow, alternatively, this scheme can also be used to treat the inverse design problem of a fan/compressor rotor blade with part-span shrouds.

Research on the explosion release method and damage mechanism of titanium alloy fan blade

Yanan Zhang,Zekan He,Chuang Liu,Meng Wang,Haijun Xuan,Mingmin Qu,Zehui Fang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

The current advanced aero-engine fan rotors are usually integrally-bladed rotor discs, and the root of the fan blade has irregular curved surface, which brings technical difficulties and challenges to achieve the blade releasing. In this paper, the dynamic response and energy dissipation process of the titanium alloy blade under shaped charge jet explosion were analyzed by numerical model, and the explosion damage mechanism of titanium alloy fan blades was clarified. Finally, a FBO test was conducted to verify the blade explosion release method in rotating state. Through the energy dissipation analysis of the whole explosion process, it can be seen that the overall residual kinetic energy of the blade is about 15.7 J, which is only 0.02 % of the initial kinetic energy of the releasing blade in rotating. It is indicated that the explosion separation method will not generate additional kinetic energy to the released blade.

환기용 축류팬의 가이드핀 블레이드 형상변화에 따른 유동특성에 관한 연구

박홍광(Hongkwang Park),이지근(Jeekeun Lee),노병준(Byungjoon Rho) 대한설비공학회 2007 설비공학 논문집 Vol.19 No.12

The effects of a guide fin blade on the flow characteristics in a ventilating axial fan were investigated experimentally. The guide fins were setup onto the pressure surface of the blade, and their effects on the flowrate were evaluated. Two types of the guide fin blade were designed. One is the stem fin blade, and the other is the radial fin blade. The stem fin is designed normal to the circumference of a circle, and the radial fin is designed along the circumference of a circle. The results from the guide fin blade fans are compared with that of the blade without guide fins. The position and the geometry of the radial fin setting up on the blade have an effect on the increase of flowrate with the minor sacrifice of rotational speed of the blades. The radial fin positioning at 0.84 times blade diameter shows highest performance in the flowrate. The increase of the blade weight resulting from applying the guide fins shows minor effect on the variation of rotational speed of the blades.

Comparative Performance Analysis of an Electric Motor Cooling Fan with Various Inlet Vent and Blade Shapes

Park, Jae-Min,Kim, Kwang-Yong,Heo, Man-Woong Korean Society for Fluid machinery 2017 International journal of fluid machinery and syste Vol.10 No.4

Electric motors are used as the main power sources in many industrial equipments and household appliances. The miniaturization and weight reduction of electric motors generally increase the internal heat generation. Therefore, it is important to understand the flow characteristics of motor cooling fans and to improve their performance. The present study aimed at systematically investigating the effects of the inlet vent and blade shapes on the aerodynamic performance of a low-voltage electric motor cooling fan. The flow characteristics of the low-voltage electric motor cooling fan was numerically analyzed using three-dimensional Reynolds-averaged Navier-Stokes equations. The $k-{\varepsilon}$ turbulence model was selected for the analysis of turbulence using a turbulence model test. An optimal grid system in the computational domain was selected through a grid dependency test. The mass flow coefficient and torque coefficient were considered as the performance parameters of the cooling fan. Eleven inlet vent shapes and eleven blade shapes of the cooling fan were tested by evaluating the aerodynamic performance of the cooling fan. The mass flow coefficient and torque coefficient were considered as the performance parameters of the motor cooling fan. Eleven inlet vent shapes on the fan cover and eleven blade shapes were tested to evaluate their effects on the mass flow coefficient and torque coefficient. The maximum mass flow coefficient of 0.0908 and the minimum torque coefficient of 0.0089, were achieved using different combinations of vent and blade shapes.

Comparative Performance Analysis of an Electric Motor Cooling Fan with Various Inlet Vent and Blade Shapes

Jae-Min Park,Kwang-Yong Kim,Man-Woong Heo 한국유체기계학회 2017 International journal of fluid machinery and syste Vol.10 No.4

Electric motors are used as the main power sources in many industrial equipments and household appliances. The miniaturization and weight reduction of electric motors generally increase the internal heat generation. Therefore, it is important to understand the flow characteristics of motor cooling fans and to improve their performance. The present study aimed at systematically investigating the effects of the inlet vent and blade shapes on the aerodynamic performance of a low-voltage electric motor cooling fan. The flow characteristics of the low-voltage electric motor cooling fan was numerically analyzed using three-dimensional Reynolds-averaged Navier-Stokes equations. The k-ε turbulence model was selected for the analysis of turbulence using a turbulence model test. An optimal grid system in the computational domain was selected through a grid dependency test. The mass flow coefficient and torque coefficient were considered as the performance parameters of the cooling fan. Eleven inlet vent shapes and eleven blade shapes of the cooling fan were tested by evaluating the aerodynamic performance of the cooling fan. The mass flow coefficient and torque coefficient were considered as the performance parameters of the motor cooling fan. Eleven inlet vent shapes on the fan cover and eleven blade shapes were tested to evaluate their effects on the mass flow coefficient and torque coefficient. The maximum mass flow coefficient of 0.0908 and the minimum torque coefficient of 0.0089, were achieved using different combinations of vent and blade shapes.

축류형 이중 블레이드 팬의 공기 유동 특성에 관한 실험적 연구

김해지(Hae-Ji Kim),이용민(Yong-Min Lee) 한국기계가공학회 2014 한국기계가공학회지 Vol.13 No.4

To ventilate indoor spaces, axial single-blade fans are widely used in various areas, such as schools, houses, offices, and restaurants. Recently, axial single-blade fans were developed to realize energy efficiency and noise reduction improvements. Here, an experimental study of the air flow characteristics of an axial dual-blade fan is conducted. The characteristics of the axial dual-blade fan were tested via an air flow analysis and with prototypes. For the performance of the fan, the flow rate, power consumption, and noise were evaluated. The result showed that the axial dual-blade fan uses less power and produces less noise in comparison with an axial single-blade fan.

Comparative Performance Analysis of an Electric Motor Cooling Fan with Various Inlet Vent and Blade Shapes

박재민,김광용,허만웅 한국유체기계학회 2017 International journal of fluid machinery and syste Vol.10 No.4

Electric motors are used as the main power sources in many industrial equipments and household appliances. The miniaturization and weight reduction of electric motors generally increase the internal heat generation. Therefore, it is important to understand the flow characteristics of motor cooling fans and to improve their performance. The present study aimed at systematically investigating the effects of the inlet vent and blade shapes on the aerodynamic performance of a low-voltage electric motor cooling fan. The flow characteristics of the low-voltage electric motor cooling fan was numerically analyzed using three-dimensional Reynolds-averaged Navier-Stokes equations. The k-ε turbulence model was selected for the analysis of turbulence using a turbulence model test. An optimal grid system in the computational domain was selected through a grid dependency test. The mass flow coefficient and torque coefficient were considered as the performance parameters of the cooling fan. Eleven inlet vent shapes and eleven blade shapes of the cooling fan were tested by evaluating the aerodynamic performance of the cooling fan. The mass flow coefficient and torque coefficient were considered as the performance parameters of the motor cooling fan. Eleven inlet vent shapes on the fan cover and eleven blade shapes were tested to evaluate their effects on the mass flow coefficient and torque coefficient. The maximum mass flow coefficient of 0.0908 and the minimum torque coefficient of 0.0089, were achieved using different combinations of vent and blade shapes.