Electrochemical machining (ECM) is an effective and economical manufacturing method for machining hard-to-cut metal materials that are often used in the aerospace field. Cathode design is very complicated in ECM and i...Electrochemical machining (ECM) is an effective and economical manufacturing method for machining hard-to-cut metal materials that are often used in the aerospace field. Cathode design is very complicated in ECM and is a core problem influencing machining accuracy, especially for complex profiles such as compressor blades in aero engines. A new cathode design method based on iterative correction of predicted profile errors in blade ECM is proposed in this paper. A mathematical model is first built according to the ECM shaping law, and a simulation is then carried out using ANSYS software. A dynamic forming process is obtained and machining gap distributions at different stages are analyzed. Additionally, the simulation deviation between the prediction profile and model is improved by the new method through correcting the initial cathode profile. Furthermore, validation experiments are conducted using cathodes designed before and after the simulation correction. Machining accuracy for the optimal cathode is improved markedly compared with that for the initial cathode. The experimental results illustrate the suitability of the new method and that it can also be applied to other complex engine components such as diffusers. (C) 2016 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.展开更多
To ameliorate reliability analysis efficiency for aeroengine components, such as compressor blade, support vector machine response surface method(SRSM) is proposed. SRSM integrates the advantages of support vector mac...To ameliorate reliability analysis efficiency for aeroengine components, such as compressor blade, support vector machine response surface method(SRSM) is proposed. SRSM integrates the advantages of support vector machine(SVM) and traditional response surface method(RSM), and utilizes experimental samples to construct a suitable response surface function(RSF) to replace the complicated and abstract finite element model. Moreover, the randomness of material parameters, structural dimension and operating condition are considered during extracting data so that the response surface function is more agreeable to the practical model. The results indicate that based on the same experimental data, SRSM has come closer than RSM reliability to approximating Monte Carlo method(MCM); while SRSM(17.296 s) needs far less running time than MCM(10958 s) and RSM(9840 s). Therefore,under the same simulation conditions, SRSM has the largest analysis efficiency, and can be considered a feasible and valid method to analyze structural reliability.展开更多
Ice causes impact damage to different positions of the compressor blade,destroys the structural integrity of the rotor structure,and then causes unbalanced failure and even causes nonlinear vibration accidents such as...Ice causes impact damage to different positions of the compressor blade,destroys the structural integrity of the rotor structure,and then causes unbalanced failure and even causes nonlinear vibration accidents such as collision and friction,which affects the execution of helicopter tasks.To investigate the influence of impact position on the damage form and dynamic response of blades during ice impact,a dynamic model by finite element-smooth particle fluid dynamic coupling method is created.The ice impact damage experiment of the TC4 plate based on the air gun experimental platform was carried out to verify the reliability of the simulation model.The damage of compressor blades impacted by ice from different positions under static and design speed of 45000 r/min is analyzed.The research results indicate that under static conditions,the damage caused by ice impact from the leading edge blade tip to the leading edge blade root first increases and then decreases,with the maximum damage occurring at the 66.7%blade height position on the leading edge.At the design speed,the closer the impact locations are to the leaf tip,the greater the damage is,and the plastic damage,equivalent stress,and kinetic energy loss of the ice impact are lower than the blade static condition.The research conclusion can provide theoretical reference and data support for the design of structural strength and protection of compressor blades in turboshaft engines.展开更多
Particle Image Velocimetry(PIV)is a well-developed and contactless technique in experimental fluid mechanics,but the strong velocity gradient and streamline curvature near the wall substantially limits its accuracy im...Particle Image Velocimetry(PIV)is a well-developed and contactless technique in experimental fluid mechanics,but the strong velocity gradient and streamline curvature near the wall substantially limits its accuracy improvement.This paper presents a data processing procedure combining conventional PIV and newly developed Mirror Interchange(MI)based Interface-PIV for the measurement of the boundary layer parameter development in the blade leading edge region.The synthetic particle images are used to analyze the measurement errors in the entire procedure.Overall,three types of errors,namely the errors caused by the Window Deformation Iterative Multigrid(WIDIM)algorithm,the discrete data interpolation and integration,and the wall offset uncertainty,comprise the main measurement error.Specifically,the errors due to the discrete data interpolation and integration and the WIDIM algorithm comprise the mean bias,which can be corrected through the error analysis method proposed in the present work.Meanwhile,the errors due to the WIDIM algorithm and the wall offset uncertainty contribute to the measurement uncertainty.Computational fluid dynamics-based synthetic particle flows were generated to verify the newly developed PIV data processing procedure and the corresponding error analysis method.Results showed that the data processing method could improve the accuracy of PIV measurements for boundary layer flows with high curvature and acceleration and even with significant flow separation bubbles.Finally,the data processing method is also applied in a PIV experiment to investigate the boundary layer flows around a compressor blade leading edge,and several credible boundary flow parameters were obtained.展开更多
Fine grain cast IN718 compressor blade form abroad has been analyzed. There is no columnar grain, uniform equiaxed grain, less segregation and no porosity cast defect in essence in the section of blade body with fine ...Fine grain cast IN718 compressor blade form abroad has been analyzed. There is no columnar grain, uniform equiaxed grain, less segregation and no porosity cast defect in essence in the section of blade body with fine grain, in which grain size is about ASTM 2 ～4. Its microstructure is approachable to that of forging. It is hopeful to achieve the goal of replacing forging by casting.展开更多
Compressor is an important part of aero engine. In the environment of high temperature and high pressure,compressor blade will suffer from several physical and chemical processes,such as centrifugal force,aerodynamic ...Compressor is an important part of aero engine. In the environment of high temperature and high pressure,compressor blade will suffer from several physical and chemical processes,such as centrifugal force,aerodynamic force vibration and oxidation. These processes will lead compressor blade to fatigue fracture,and at the same time,make negative effects on the engine’ s overall performance. Based on the software ANSYS15. 0,we made strength analysis and modal analysis of compressor blade in this paper. As a result,we got its natural frequencies,relevant modal parameters and vibration mode cloud pictures. After analyzing the influence that centrifugal force made on modal parameters,we predicted the expected damage of the blade. Eventually the analysis results will provide the basis for overall performance evaluation,structural crack detection,fatigue life estimation and strength calculation of aircraft engine compressor.展开更多
This paper presents comparative numerical studies to investigate the effects of blade sweep on inlet flow in axial compressor cascades. A series of swept and straight cascades was modeled in order to obtain a general ...This paper presents comparative numerical studies to investigate the effects of blade sweep on inlet flow in axial compressor cascades. A series of swept and straight cascades was modeled in order to obtain a general understanding of the inlet flow field that is induced by sweep.A computational fluid dynamics（CFD） package was used to simulate the cascades and obtain the required three-dimensional（3D） flow parameters. A circumferentially averaged method was introduced which provided the circumferential fluctuation（CF） terms in the momentum equation.A program for data reduction was conducted to obtain a circumferentially averaged flow field.The influences of the inlet flow fields of the cascades were studied and spanwise distributions of each term in the momentum equation were analyzed. The results indicate that blade sweep does affect inlet radial equilibrium. The characteristic of radial fluid transfer is changed and thus influencing the axial velocity distributions. The inlet flow field varies mainly due to the combined effect of the radial pressure gradient and the CF component. The axial velocity varies consistently with the incidence variation induced by the sweep, as observed in the previous literature. In addition, factors that might influence the radial equilibrium such as blade camber angles, solidity and the effect of the distance from the leading edge are also taken into consideration and comparatively analyzed.展开更多
To control the transition process in a laminar separation bubble(LSB)over an ultra-high load compressor blade at a Re of 1.5×10^(5),the effects of wall heat transfer were considered and numerically investigated b...To control the transition process in a laminar separation bubble(LSB)over an ultra-high load compressor blade at a Re of 1.5×10^(5),the effects of wall heat transfer were considered and numerically investigated by large eddy simulations(LES).Compared with the adiabatic wall condition,the local kinematic viscosity of airflow was reduced by wall cooling;thus the effects of turbulent dissipation on the growth of fluctuations were weakened.As such,the transition occurred much earlier,and the size of LSB became smaller.On the cooled surface,the spanwise vortices deformed much more rapidly and the size of hairpin vortex structures was decreased.Furthermore,the rolling-up of 3D hairpin vortices and the ejection and sweeping process very close to the blade surface was weakened.Correspondingly,the aerodynamic losses of the compressor blade were reduced by 18.2%and 38.4%for the two cooled wall conditions.The results demonstrated the feasibility of wall cooling in controlling the transition within an LSB and reducing the aerodynamic loss of an ultra-highly loaded compressor blade.展开更多
A cold compressor blade deforms elastically under aerodynamic and centrifugal loads during operation,transforming into a hot blade configuration.Blade deformation has a significant effect on the performance of compres...A cold compressor blade deforms elastically under aerodynamic and centrifugal loads during operation,transforming into a hot blade configuration.Blade deformation has a significant effect on the performance of compressor.A nonlinear pre⁃deformation method for compressor rotor blade was developed with consideration of the nonlinear features of blade stiffness and load which varies with blade configuration.In the blade profile design phase,the method can be used to compensate the aeroelastic deformation of the blade during operation.The adverse effects of blade deflection on compressor performance and structure can be avoided by the pre⁃deformation method.Due to the fact that the nonlinear method is sensitive to initial value,a load incremental method was applied to calculate initial blade deformation to stabilize and accelerate the pre⁃deformation method.The developed method was used to predict the manufactured configuration of the Stage 37 rotor blade.The variation rules of aerodynamic and structure parameters of the pre⁃deformed blade were analyzed under off⁃design conditions.Results show that the developed method ensures that under the design condition there was a good match between the actual blade configuration during operation and the intended design blade profile.The blade untwist angle of pre⁃deformed blade could be 0°at design point.Meanwhile,the tip clearance only decreased 0.2%.When the working speed was faster than 80%design speed,the performance of the pre⁃deformed blade agreed with that of the design blade.However,the mass flow rate and the total pressure ratio of the pre⁃deformed blade were lower at low speeds.展开更多
Blade vibration failure is one of the main failure modes of compressor wheel of turbocharger for vehicle application. The existing models for evaluating the reliability of blade vibration of compressor wheel are stati...Blade vibration failure is one of the main failure modes of compressor wheel of turbocharger for vehicle application. The existing models for evaluating the reliability of blade vibration of compressor wheel are static, and can not reflect the relationship between the reliability of compressor wheel with blade vibration failure mode and the life parameter. For the blade vibration failure mode of compressor wheel of turbocharger, the reliability evaluation method is studied. Taking a compressor wheel of turbocharger for vehicle application as an example, the blade vibration characteristics and how they change with the operating parameters of turbocharger are analyzed. The failure criterion for blade vibration mode of compressor wheel is built with the Campbell diagram, and taking the effect of the dispersity of blade natural vibration frequency and randomness of turbocharger operating speed into account, time-dependent reliability models of compressor wheel with blade vibration failure mode are derived, which embody the parameters of blade natural vibration frequency, turbocharger operating speed, the blade number of compressor wheel, life index and minimum number of resonance, etc. Finally, the rule governing the reliability and failure rate of compressor wheel and the method for determining the reliable life of compressor with blade vibration is presented. A method is proposed to evaluate the reliability of compressor wheel with blade vibration failure mode time-dependently.展开更多
An experimental and numerical study was conducted to investigate the forced response of blade vibration induced by rotating stall in a low speed axial compressor.Measurements have been made of the transient stalling p...An experimental and numerical study was conducted to investigate the forced response of blade vibration induced by rotating stall in a low speed axial compressor.Measurements have been made of the transient stalling process in a low speed axial compressor stage.The CFD study was performed using solution of 3-dimensional Navier-Stokes equations,coupled with structure finite element models for the blades to identify modal shapes and structural deformations simultaneously.Interactions between fluid and structure were managed in a coupled manner,based on the interface information exchange until convergence in each time step.Based on the rotating stall measurement data obtained from a low speed axial compressor,the blade aeroelastic response induced by the rotating stall flow field was analyzed to study the vibration characteristics and the correlation between the phenomena.With this approach,good agreement between the numerical results and the experimental data was observed.The flow phenomena were well captured,and the results indicate that the rotating field stall plays a significant role in the blade vibration and stress affected by the flow excitation.展开更多
Previous studies showed that an axisymmetric hub-initiated disturbance defined as partial surge may initiate the stall of a transonic compressor; to reveal the instability evolution under full-span incompressible flow...Previous studies showed that an axisymmetric hub-initiated disturbance defined as partial surge may initiate the stall of a transonic compressor; to reveal the instability evolution under full-span incompressible flow for different levels of hub loading and B parameter, an experimental investigation is conducted on a single-stage low-speed compressor. Experimental results show that under a uniform inflow condition without inlet flow distortion, a modal-type stall inception dominates in this low-speed compressor. When an inlet screen introducing hub distortion is used to increase the hub loading, a compressor stall is initiated by a modal wave, but large disturbances are present in the hub region before the compressor stall, which become stronger as the hub loading increases. Under high hub loading and large B parameter（implemented by adding hub distortion through an inlet screen and enlarging the outlet plenum volume, respectively）, a compressor stall is triggered by an axisymmetric hub-initiated disturbance, which is much different from the modal-like disturbances. The beginning of this axisymmetric disturbance may be captured over 800 rotor revolutions prior to the onset of stall, and the amplitude grows with time. The disturbance is hub-initiated because the disturbance signal at the hub is detected much earlier than that at the tip; meanwhile, the frequency of this axisymmetric disturbance changes with the length of the inlet duct. The characteristics of instability evolution in the low-speed compressor are also compared with those in a transonic compressor.展开更多
The average-passage equation system （APES） provides a rigorous mathematical framework for account- ing for the unsteady blade row interaction through multistage compressors in steady state environment by introducing...The average-passage equation system （APES） provides a rigorous mathematical framework for account- ing for the unsteady blade row interaction through multistage compressors in steady state environment by introducing de- terministic correlations （DC） that need to be modeled to close the equation system. The primary purpose of this study was to provide insight into the DC characteristics and the in- fluence of DC on the time-averaged flow field of the APES. In Part 2 of this two-part paper, the influence of DC on the time-averaged flow field was systematically studied; Several time-averaging computations boundary conditions and DC were conducted with various for the downstream stator in a transonic compressor stage, by employing the CFD solver developed in Part 1 of this two-part paper. These results were compared with the time-averaged unsteady flow field and the steady one. The study indicat;d that the circumferential- averaged DC can take into account major part of the unsteady effects on spanwise redistribution of flow fields in compres- sors. Furthermore, it demonstrated that both deterministic stresses and deterministic enthalpy fluxes are necessary to reproduce the time-averaged flow field.展开更多
Vibration fatigue is the main failure mode of compressor blade. Evaluating the vibration stress of blade that leads to cracking is very useful for analysis of vibration fatigue. In this paper, fatigue stress estimatio...Vibration fatigue is the main failure mode of compressor blade. Evaluating the vibration stress of blade that leads to cracking is very useful for analysis of vibration fatigue. In this paper, fatigue stress estimation methods by quantitative fractography were studied through experimental blade and in-service first-stage compressor blade in order to evaluate the initiation vibration stress of in-service blade. The analysis process of initiation vibration stress was established. The evaluating result of vibration stress of in-service blade subjected to centrifugal force and bending vibration stress agrees with aero engine test result. It is shown that the evaluation method can not only evaluate the equivalent fatigue stresses of different crack depths but also yield the initiation equivalent fatigue stress.展开更多
Compared with a straight blade, a unique compressor blade integratedforward-swept and positive-curved stacking line is studied experimentally. Aerodynamic parameters ofthe two cascades are measured by a five-hole prob...Compared with a straight blade, a unique compressor blade integratedforward-swept and positive-curved stacking line is studied experimentally. Aerodynamic parameters ofthe two cascades are measured by a five-hole probe at different positions and ink trace flowvisualization is conducted on blade surfaces. The result shows that the swept-curved cascade haslower endwall loss and higher midspan loss as compared with the straight cascade. However, lowerloss is accompanied with lower diffusion factor. Opposite 'C' shape static pressure distribution isestablished on the suction surface of the swept-curved blade, which is helpful for avoiding theaccumulation of low energy fluid in the endwall corner region. Anyhow the studies support theconclusion that the swept-curved blade conduces to not only the reduction of overall loss but alsothe improvement of stable operation in the endwall corner region.展开更多
This paper presents the aspirated modification of a dual-stage counter-rotating compressor which contains inlet guide vanes（IGVs）, two counter-rotating rotors（R1, R2）, and outlet guide vanes（OGVs）.Uniform circul...This paper presents the aspirated modification of a dual-stage counter-rotating compressor which contains inlet guide vanes（IGVs）, two counter-rotating rotors（R1, R2）, and outlet guide vanes（OGVs）.Uniform circular holes are circumferentially distributed over the rotors＇ tips on the shroud casing which are designed to remove the low-energy fluid near the shroud casing.OGVs are hollow blades with two slots designed on the suction side which can better control the flow on the suction surface through boundary layer suction.Related works about the experiments have been carried out since June 2012 and the effect of flow suction on the performance of the compressor is investigated in detail.Characteristic lines at a 70% corrected rotating speed are tested and those with higher rotating speeds will be studied in the near future.Experimental results indicate that boundary layer suction can improve the compressor characteristics and the best suction methodology varies along the operating line.At the near stall condition, suction from the R2 tip region can obviously increase the efficiency and the total pressure ratio, as well as improve the flow capacity.Isentropic efficiency can be maximally increased by 4.24% with an increase of 1.94% in massflow under a suction flow of 160 m3/h.Suction at the R1 position with a suction rate below 0.35% in a high flow situation can make the performance of the compressor better than others.Around the peak efficiency point, boundary layer suction from the slots of OGVs is the best choice in improving the efficiency, but it causes a 0.1% loss in the total pressure ratio.展开更多
The impact of boundary layer suction on the aerodynamic performance of a high-turning compressor cascade was numerically simulated and discussed.The aerodynamic performance of a curved and a straight cascade with and ...The impact of boundary layer suction on the aerodynamic performance of a high-turning compressor cascade was numerically simulated and discussed.The aerodynamic performance of a curved and a straight cascade with and without boundary layer suction were comparatively studied at several suction flow rates.The results showed that boundary layer suction dramatically improved the flow behavior within the flow passage.Moreover,higher loading over the whole blade height,lower total pressure loss,and higher passage throughflow were achieved with a relatively small amount of boundary layer removal.The integration of curved blade and boundary layer suction contributed to better aerodynamic performance than the cascades with only curved blade or boundary layer suction used,and the more favorable effect resulted from the weakening of the three dimensional effects of the boundary layer close to the endwalls.展开更多
Based on the investigation of mid-span local boundary layer suction and positive bowed cascade, a coupled local tailored boundary layer suction and positive bowed blade method is developed to improve the performance o...Based on the investigation of mid-span local boundary layer suction and positive bowed cascade, a coupled local tailored boundary layer suction and positive bowed blade method is developed to improve the performance of a highly loaded diffusion cascade with less suction slot. The effectiveness of the coupled method under different inlet boundary layers is also investigated.Results show that mid-span local boundary layer suction can effectively remove trailing edge separation, but deteriorate the flow fields near the endwall. The positive bowed cascade is beneficial for reducing open corner separation, but is detrimental to mid-span flow fields. The coupled method can further improve the performance and flow field of the cascade. The mid-span trailing edge separation and open corner separation are eliminated. Compared with linear cascade with suction, the coupled method reduces overall loss of the cascade by 31.4% at most. The mid-span loss of the cascade decreases as the suction coefficient increases, but increases as bow angle increases. The endwall loss increases as the suction coefficient increases. By contrast, the endwall loss decreases significantly as the bow angle increases. The endwall loss of coupled controlled cascade is higher than that of bowed cascade with the same bow angle because of the spanwise inverse ‘‘C＂ shaped static pressure distribution. Under different inlet boundary layer conditions, the coupled method can also improve the cascade effectively.展开更多
A comparison of the results of a computational simulation and an experimental measurement indicates a good agreement between them： the bowed blade lowers the energy loss coefficient of engine by 11% in the simulation...A comparison of the results of a computational simulation and an experimental measurement indicates a good agreement between them： the bowed blade lowers the energy loss coefficient of engine by 11% in the simulation and by 13% in the measurement. To further discuss the application conditions of bowed blade in compressor, with incidence equal to zero and other boundary conditions unchanged, a computational investigations on four series of linear stators with different aerofoil turning angles are achieved. It is found that the bowed blade has much positive effect in high airfoil turning angle cascade, for example, the optimal retrofit of 30° bow angle highly reduces the energy loss coefficient by 17.9%, when the aerofoil turning angle is 59.5 °. But the optimal retrofit of 15° has only 0.7% reduction when the aerofoil turning angle is 39.5°, or even the compressor performance will get worse with the bow angle gradually increasing. Consequently, it is verified that the turning angle is one of the important factors to decide whether to apply the bowed blade into compressor at low Math number.展开更多
An opti mization process is used to redesign blades of a high-pressure compressor.An artificial neural network (ANN) method is coupled to Navier-Stokes solvers and is applied to three different redesigns.A newrotor bl...An opti mization process is used to redesign blades of a high-pressure compressor.An artificial neural network (ANN) method is coupled to Navier-Stokes solvers and is applied to three different redesigns.A newrotor blade of a transonic compressor is designed by modifying thick,stacking line andinlet angle using a 3Dapproach,with a significant efficiencyi mprovement at the design point.The off-design behavior of this new compressor is also checked afterwards,which shows that the whole performance of the inlet stage is improved over a wide range of mass flow.The losses are reduced,proving the good performance of the opti mum.The whole results indicate that the opti mization method can find i mproved design and can be integrated in a design procedure.展开更多
基金co-supported by the National Natural Science Foundation of China (No. 51205199)the Natural Science Foundation of Jiangsu Province (No. BK2012387)the Fundamental Research Funds for the Central Universities (No. NE 2015105)
文摘Electrochemical machining (ECM) is an effective and economical manufacturing method for machining hard-to-cut metal materials that are often used in the aerospace field. Cathode design is very complicated in ECM and is a core problem influencing machining accuracy, especially for complex profiles such as compressor blades in aero engines. A new cathode design method based on iterative correction of predicted profile errors in blade ECM is proposed in this paper. A mathematical model is first built according to the ECM shaping law, and a simulation is then carried out using ANSYS software. A dynamic forming process is obtained and machining gap distributions at different stages are analyzed. Additionally, the simulation deviation between the prediction profile and model is improved by the new method through correcting the initial cathode profile. Furthermore, validation experiments are conducted using cathodes designed before and after the simulation correction. Machining accuracy for the optimal cathode is improved markedly compared with that for the initial cathode. The experimental results illustrate the suitability of the new method and that it can also be applied to other complex engine components such as diffusers. (C) 2016 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.
基金Project(51335003)supported by the National Natural Science Foundation of ChinaProject(20111102110011)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘To ameliorate reliability analysis efficiency for aeroengine components, such as compressor blade, support vector machine response surface method(SRSM) is proposed. SRSM integrates the advantages of support vector machine(SVM) and traditional response surface method(RSM), and utilizes experimental samples to construct a suitable response surface function(RSF) to replace the complicated and abstract finite element model. Moreover, the randomness of material parameters, structural dimension and operating condition are considered during extracting data so that the response surface function is more agreeable to the practical model. The results indicate that based on the same experimental data, SRSM has come closer than RSM reliability to approximating Monte Carlo method(MCM); while SRSM(17.296 s) needs far less running time than MCM(10958 s) and RSM(9840 s). Therefore,under the same simulation conditions, SRSM has the largest analysis efficiency, and can be considered a feasible and valid method to analyze structural reliability.
基金supported by the National Natural Science Foundation of China(Grant Nos.52175091 and 52075165)the National Natural Science Foundation of Hunan Province(Grant No.2023JJ30247)+1 种基金the Key Research and Development Program of Hunan Province(Grant No.2022GK2023)the AECC Independent Innovation Special Foundation(Grant No.KY-1003-2021-0019).
文摘Ice causes impact damage to different positions of the compressor blade,destroys the structural integrity of the rotor structure,and then causes unbalanced failure and even causes nonlinear vibration accidents such as collision and friction,which affects the execution of helicopter tasks.To investigate the influence of impact position on the damage form and dynamic response of blades during ice impact,a dynamic model by finite element-smooth particle fluid dynamic coupling method is created.The ice impact damage experiment of the TC4 plate based on the air gun experimental platform was carried out to verify the reliability of the simulation model.The damage of compressor blades impacted by ice from different positions under static and design speed of 45000 r/min is analyzed.The research results indicate that under static conditions,the damage caused by ice impact from the leading edge blade tip to the leading edge blade root first increases and then decreases,with the maximum damage occurring at the 66.7%blade height position on the leading edge.At the design speed,the closer the impact locations are to the leaf tip,the greater the damage is,and the plastic damage,equivalent stress,and kinetic energy loss of the ice impact are lower than the blade static condition.The research conclusion can provide theoretical reference and data support for the design of structural strength and protection of compressor blades in turboshaft engines.
基金funded by the National Natural Science Foundation of China(Nos.51790511 and 51806004)the National Science and Technology Major Project,China(No.2017-II-0001-0013).
文摘Particle Image Velocimetry(PIV)is a well-developed and contactless technique in experimental fluid mechanics,but the strong velocity gradient and streamline curvature near the wall substantially limits its accuracy improvement.This paper presents a data processing procedure combining conventional PIV and newly developed Mirror Interchange(MI)based Interface-PIV for the measurement of the boundary layer parameter development in the blade leading edge region.The synthetic particle images are used to analyze the measurement errors in the entire procedure.Overall,three types of errors,namely the errors caused by the Window Deformation Iterative Multigrid(WIDIM)algorithm,the discrete data interpolation and integration,and the wall offset uncertainty,comprise the main measurement error.Specifically,the errors due to the discrete data interpolation and integration and the WIDIM algorithm comprise the mean bias,which can be corrected through the error analysis method proposed in the present work.Meanwhile,the errors due to the WIDIM algorithm and the wall offset uncertainty contribute to the measurement uncertainty.Computational fluid dynamics-based synthetic particle flows were generated to verify the newly developed PIV data processing procedure and the corresponding error analysis method.Results showed that the data processing method could improve the accuracy of PIV measurements for boundary layer flows with high curvature and acceleration and even with significant flow separation bubbles.Finally,the data processing method is also applied in a PIV experiment to investigate the boundary layer flows around a compressor blade leading edge,and several credible boundary flow parameters were obtained.
文摘Fine grain cast IN718 compressor blade form abroad has been analyzed. There is no columnar grain, uniform equiaxed grain, less segregation and no porosity cast defect in essence in the section of blade body with fine grain, in which grain size is about ASTM 2 ～4. Its microstructure is approachable to that of forging. It is hopeful to achieve the goal of replacing forging by casting.
文摘Compressor is an important part of aero engine. In the environment of high temperature and high pressure,compressor blade will suffer from several physical and chemical processes,such as centrifugal force,aerodynamic force vibration and oxidation. These processes will lead compressor blade to fatigue fracture,and at the same time,make negative effects on the engine’ s overall performance. Based on the software ANSYS15. 0,we made strength analysis and modal analysis of compressor blade in this paper. As a result,we got its natural frequencies,relevant modal parameters and vibration mode cloud pictures. After analyzing the influence that centrifugal force made on modal parameters,we predicted the expected damage of the blade. Eventually the analysis results will provide the basis for overall performance evaluation,structural crack detection,fatigue life estimation and strength calculation of aircraft engine compressor.
基金support of the National Natural Science Foundation of China(Grant Nos:51236001,51006005)
文摘This paper presents comparative numerical studies to investigate the effects of blade sweep on inlet flow in axial compressor cascades. A series of swept and straight cascades was modeled in order to obtain a general understanding of the inlet flow field that is induced by sweep.A computational fluid dynamics（CFD） package was used to simulate the cascades and obtain the required three-dimensional（3D） flow parameters. A circumferentially averaged method was introduced which provided the circumferential fluctuation（CF） terms in the momentum equation.A program for data reduction was conducted to obtain a circumferentially averaged flow field.The influences of the inlet flow fields of the cascades were studied and spanwise distributions of each term in the momentum equation were analyzed. The results indicate that blade sweep does affect inlet radial equilibrium. The characteristic of radial fluid transfer is changed and thus influencing the axial velocity distributions. The inlet flow field varies mainly due to the combined effect of the radial pressure gradient and the CF component. The axial velocity varies consistently with the incidence variation induced by the sweep, as observed in the previous literature. In addition, factors that might influence the radial equilibrium such as blade camber angles, solidity and the effect of the distance from the leading edge are also taken into consideration and comparatively analyzed.
基金the financial support of the Science Center for Gas Turbine Project(2022-B-Ⅱ-008)Open project of the State Key Laboratory of Aerodynamics(SKLA-20190105)。
文摘To control the transition process in a laminar separation bubble(LSB)over an ultra-high load compressor blade at a Re of 1.5×10^(5),the effects of wall heat transfer were considered and numerically investigated by large eddy simulations(LES).Compared with the adiabatic wall condition,the local kinematic viscosity of airflow was reduced by wall cooling;thus the effects of turbulent dissipation on the growth of fluctuations were weakened.As such,the transition occurred much earlier,and the size of LSB became smaller.On the cooled surface,the spanwise vortices deformed much more rapidly and the size of hairpin vortex structures was decreased.Furthermore,the rolling-up of 3D hairpin vortices and the ejection and sweeping process very close to the blade surface was weakened.Correspondingly,the aerodynamic losses of the compressor blade were reduced by 18.2%and 38.4%for the two cooled wall conditions.The results demonstrated the feasibility of wall cooling in controlling the transition within an LSB and reducing the aerodynamic loss of an ultra-highly loaded compressor blade.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51606023)the Fundamental Research Funds for the Central Universities(Grant No.3132019204).
文摘A cold compressor blade deforms elastically under aerodynamic and centrifugal loads during operation,transforming into a hot blade configuration.Blade deformation has a significant effect on the performance of compressor.A nonlinear pre⁃deformation method for compressor rotor blade was developed with consideration of the nonlinear features of blade stiffness and load which varies with blade configuration.In the blade profile design phase,the method can be used to compensate the aeroelastic deformation of the blade during operation.The adverse effects of blade deflection on compressor performance and structure can be avoided by the pre⁃deformation method.Due to the fact that the nonlinear method is sensitive to initial value,a load incremental method was applied to calculate initial blade deformation to stabilize and accelerate the pre⁃deformation method.The developed method was used to predict the manufactured configuration of the Stage 37 rotor blade.The variation rules of aerodynamic and structure parameters of the pre⁃deformed blade were analyzed under off⁃design conditions.Results show that the developed method ensures that under the design condition there was a good match between the actual blade configuration during operation and the intended design blade profile.The blade untwist angle of pre⁃deformed blade could be 0°at design point.Meanwhile,the tip clearance only decreased 0.2%.When the working speed was faster than 80%design speed,the performance of the pre⁃deformed blade agreed with that of the design blade.However,the mass flow rate and the total pressure ratio of the pre⁃deformed blade were lower at low speeds.
基金supported by National Natural Science Foundation of China(Grant Nos.51375465,50905007)
文摘Blade vibration failure is one of the main failure modes of compressor wheel of turbocharger for vehicle application. The existing models for evaluating the reliability of blade vibration of compressor wheel are static, and can not reflect the relationship between the reliability of compressor wheel with blade vibration failure mode and the life parameter. For the blade vibration failure mode of compressor wheel of turbocharger, the reliability evaluation method is studied. Taking a compressor wheel of turbocharger for vehicle application as an example, the blade vibration characteristics and how they change with the operating parameters of turbocharger are analyzed. The failure criterion for blade vibration mode of compressor wheel is built with the Campbell diagram, and taking the effect of the dispersity of blade natural vibration frequency and randomness of turbocharger operating speed into account, time-dependent reliability models of compressor wheel with blade vibration failure mode are derived, which embody the parameters of blade natural vibration frequency, turbocharger operating speed, the blade number of compressor wheel, life index and minimum number of resonance, etc. Finally, the rule governing the reliability and failure rate of compressor wheel and the method for determining the reliable life of compressor with blade vibration is presented. A method is proposed to evaluate the reliability of compressor wheel with blade vibration failure mode time-dependently.
基金National Natural Science Foundation(60934001)Science Fund of State Key Laboratory of Automotive Safety and Energy(KF11051)
文摘An experimental and numerical study was conducted to investigate the forced response of blade vibration induced by rotating stall in a low speed axial compressor.Measurements have been made of the transient stalling process in a low speed axial compressor stage.The CFD study was performed using solution of 3-dimensional Navier-Stokes equations,coupled with structure finite element models for the blades to identify modal shapes and structural deformations simultaneously.Interactions between fluid and structure were managed in a coupled manner,based on the interface information exchange until convergence in each time step.Based on the rotating stall measurement data obtained from a low speed axial compressor,the blade aeroelastic response induced by the rotating stall flow field was analyzed to study the vibration characteristics and the correlation between the phenomena.With this approach,good agreement between the numerical results and the experimental data was observed.The flow phenomena were well captured,and the results indicate that the rotating field stall plays a significant role in the blade vibration and stress affected by the flow excitation.
基金the supports of the National Natural Science Foundation of China (Nos.51636001 and 51706008)Aeronautics Power Foundation of China (No.6141B090315)China Postdoctoral Science Foundation (No.2017M610742)
文摘Previous studies showed that an axisymmetric hub-initiated disturbance defined as partial surge may initiate the stall of a transonic compressor; to reveal the instability evolution under full-span incompressible flow for different levels of hub loading and B parameter, an experimental investigation is conducted on a single-stage low-speed compressor. Experimental results show that under a uniform inflow condition without inlet flow distortion, a modal-type stall inception dominates in this low-speed compressor. When an inlet screen introducing hub distortion is used to increase the hub loading, a compressor stall is initiated by a modal wave, but large disturbances are present in the hub region before the compressor stall, which become stronger as the hub loading increases. Under high hub loading and large B parameter（implemented by adding hub distortion through an inlet screen and enlarging the outlet plenum volume, respectively）, a compressor stall is triggered by an axisymmetric hub-initiated disturbance, which is much different from the modal-like disturbances. The beginning of this axisymmetric disturbance may be captured over 800 rotor revolutions prior to the onset of stall, and the amplitude grows with time. The disturbance is hub-initiated because the disturbance signal at the hub is detected much earlier than that at the tip; meanwhile, the frequency of this axisymmetric disturbance changes with the length of the inlet duct. The characteristics of instability evolution in the low-speed compressor are also compared with those in a transonic compressor.
基金supported by the National Natural Science Foundation of China (51006006,51136003,50976010,50976009)the National Basic Research Program of China (2012CB72 0205)+2 种基金the Aeronautical Science Foundation of China (2010ZB51)the 111 Project (B08009)the National Science Special Foundation for Post-doctoral Scientists of China (201104049)
文摘The average-passage equation system （APES） provides a rigorous mathematical framework for account- ing for the unsteady blade row interaction through multistage compressors in steady state environment by introducing de- terministic correlations （DC） that need to be modeled to close the equation system. The primary purpose of this study was to provide insight into the DC characteristics and the in- fluence of DC on the time-averaged flow field of the APES. In Part 2 of this two-part paper, the influence of DC on the time-averaged flow field was systematically studied; Several time-averaging computations boundary conditions and DC were conducted with various for the downstream stator in a transonic compressor stage, by employing the CFD solver developed in Part 1 of this two-part paper. These results were compared with the time-averaged unsteady flow field and the steady one. The study indicat;d that the circumferential- averaged DC can take into account major part of the unsteady effects on spanwise redistribution of flow fields in compres- sors. Furthermore, it demonstrated that both deterministic stresses and deterministic enthalpy fluxes are necessary to reproduce the time-averaged flow field.
基金financially supported by Equipment Advance Research Fund of China (No. 9140A1211HK51)
文摘Vibration fatigue is the main failure mode of compressor blade. Evaluating the vibration stress of blade that leads to cracking is very useful for analysis of vibration fatigue. In this paper, fatigue stress estimation methods by quantitative fractography were studied through experimental blade and in-service first-stage compressor blade in order to evaluate the initiation vibration stress of in-service blade. The analysis process of initiation vibration stress was established. The evaluating result of vibration stress of in-service blade subjected to centrifugal force and bending vibration stress agrees with aero engine test result. It is shown that the evaluation method can not only evaluate the equivalent fatigue stresses of different crack depths but also yield the initiation equivalent fatigue stress.
文摘Compared with a straight blade, a unique compressor blade integratedforward-swept and positive-curved stacking line is studied experimentally. Aerodynamic parameters ofthe two cascades are measured by a five-hole probe at different positions and ink trace flowvisualization is conducted on blade surfaces. The result shows that the swept-curved cascade haslower endwall loss and higher midspan loss as compared with the straight cascade. However, lowerloss is accompanied with lower diffusion factor. Opposite 'C' shape static pressure distribution isestablished on the suction surface of the swept-curved blade, which is helpful for avoiding theaccumulation of low energy fluid in the endwall corner region. Anyhow the studies support theconclusion that the swept-curved blade conduces to not only the reduction of overall loss but alsothe improvement of stable operation in the endwall corner region.
基金supported by the National Natural Science Foundation of China (No.51236006)Advanced Aeroengine Collaborative Innovation Center
文摘This paper presents the aspirated modification of a dual-stage counter-rotating compressor which contains inlet guide vanes（IGVs）, two counter-rotating rotors（R1, R2）, and outlet guide vanes（OGVs）.Uniform circular holes are circumferentially distributed over the rotors＇ tips on the shroud casing which are designed to remove the low-energy fluid near the shroud casing.OGVs are hollow blades with two slots designed on the suction side which can better control the flow on the suction surface through boundary layer suction.Related works about the experiments have been carried out since June 2012 and the effect of flow suction on the performance of the compressor is investigated in detail.Characteristic lines at a 70% corrected rotating speed are tested and those with higher rotating speeds will be studied in the near future.Experimental results indicate that boundary layer suction can improve the compressor characteristics and the best suction methodology varies along the operating line.At the near stall condition, suction from the R2 tip region can obviously increase the efficiency and the total pressure ratio, as well as improve the flow capacity.Isentropic efficiency can be maximally increased by 4.24% with an increase of 1.94% in massflow under a suction flow of 160 m3/h.Suction at the R1 position with a suction rate below 0.35% in a high flow situation can make the performance of the compressor better than others.Around the peak efficiency point, boundary layer suction from the slots of OGVs is the best choice in improving the efficiency, but it causes a 0.1% loss in the total pressure ratio.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50646021).
文摘The impact of boundary layer suction on the aerodynamic performance of a high-turning compressor cascade was numerically simulated and discussed.The aerodynamic performance of a curved and a straight cascade with and without boundary layer suction were comparatively studied at several suction flow rates.The results showed that boundary layer suction dramatically improved the flow behavior within the flow passage.Moreover,higher loading over the whole blade height,lower total pressure loss,and higher passage throughflow were achieved with a relatively small amount of boundary layer removal.The integration of curved blade and boundary layer suction contributed to better aerodynamic performance than the cascades with only curved blade or boundary layer suction used,and the more favorable effect resulted from the weakening of the three dimensional effects of the boundary layer close to the endwalls.
基金supported by China Postdoctoral Science Foundationa key project of the National Natural Science Foundation of China (No. 51236006)
文摘Based on the investigation of mid-span local boundary layer suction and positive bowed cascade, a coupled local tailored boundary layer suction and positive bowed blade method is developed to improve the performance of a highly loaded diffusion cascade with less suction slot. The effectiveness of the coupled method under different inlet boundary layers is also investigated.Results show that mid-span local boundary layer suction can effectively remove trailing edge separation, but deteriorate the flow fields near the endwall. The positive bowed cascade is beneficial for reducing open corner separation, but is detrimental to mid-span flow fields. The coupled method can further improve the performance and flow field of the cascade. The mid-span trailing edge separation and open corner separation are eliminated. Compared with linear cascade with suction, the coupled method reduces overall loss of the cascade by 31.4% at most. The mid-span loss of the cascade decreases as the suction coefficient increases, but increases as bow angle increases. The endwall loss increases as the suction coefficient increases. By contrast, the endwall loss decreases significantly as the bow angle increases. The endwall loss of coupled controlled cascade is higher than that of bowed cascade with the same bow angle because of the spanwise inverse ‘‘C＂ shaped static pressure distribution. Under different inlet boundary layer conditions, the coupled method can also improve the cascade effectively.
基金National Natural Science Foundation of China(50236020).
文摘A comparison of the results of a computational simulation and an experimental measurement indicates a good agreement between them： the bowed blade lowers the energy loss coefficient of engine by 11% in the simulation and by 13% in the measurement. To further discuss the application conditions of bowed blade in compressor, with incidence equal to zero and other boundary conditions unchanged, a computational investigations on four series of linear stators with different aerofoil turning angles are achieved. It is found that the bowed blade has much positive effect in high airfoil turning angle cascade, for example, the optimal retrofit of 30° bow angle highly reduces the energy loss coefficient by 17.9%, when the aerofoil turning angle is 59.5 °. But the optimal retrofit of 15° has only 0.7% reduction when the aerofoil turning angle is 39.5°, or even the compressor performance will get worse with the bow angle gradually increasing. Consequently, it is verified that the turning angle is one of the important factors to decide whether to apply the bowed blade into compressor at low Math number.
文摘An opti mization process is used to redesign blades of a high-pressure compressor.An artificial neural network (ANN) method is coupled to Navier-Stokes solvers and is applied to three different redesigns.A newrotor blade of a transonic compressor is designed by modifying thick,stacking line andinlet angle using a 3Dapproach,with a significant efficiencyi mprovement at the design point.The off-design behavior of this new compressor is also checked afterwards,which shows that the whole performance of the inlet stage is improved over a wide range of mass flow.The losses are reduced,proving the good performance of the opti mum.The whole results indicate that the opti mization method can find i mproved design and can be integrated in a design procedure.
