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Abstract :
Artificial neural network (ANN) methods have been rapidly developed and applied in solving nonlinear small sample problems. In this paper, an improved particle swarm algorithm optimized back propagation neural network (IMPSO-BPNN) method was proposed and used for the regression analysis and prediction of 20% (volume fraction) hydrogen enriched compressed natural gas (HCNG) engine performance. Meanwhile, various ANN and support vector machine (SVM) methods were also utilized for a comparative study. The experimental results show that the HCNG engine has the highest combustion efficiency, the maximum output torque and the minimum brake specific fuel consumption (BSFC) when operating at the maximum brake torque (MBT) timing, and the brake specific NOx (BSNOx) is also at a relatively low level. Through the comparison of multiple methods, the prediction accuracy and generalization ability of the IMPSO-BPNN model are the best overall. For example, the mean absolute percentage error (MAPE) of the optimal IMPSO-BPNN model (0.771%) is 5.85%, 12.62%, 17.96%, 7.57% and 7.88% less than that of the PSO-BPNN, GA-BPNN, BPNN, PSO-SVM and GA-SVM models (0.819%, 0.882%, 0.940%, 0.834% and 0.837%), respectively; and the correlation coefficient (R) is also higher than that of other models (0.99986). Secondly, the method shows visible superiority in the temporal dimension compared with the methods optimized by genetic algorithm and SVM method. For example, the CPU running time of the optimal IMPSO-BPNN model is reduced by 1773.32%, 149.74% and 1231.34% compared to that of the optimal GA-BPNN, PSO-SVM and GA-SVM models, respectively. Since the IMPSO-BPNN method is a flexible and general method, it is a new idea for the study of engine electronic control calibration tools. © 2022 Elsevier Ltd
Keyword :
Brakes Compressed natural gas Engines Forecasting Genetic algorithms Hydrogen Neural networks Particle swarm optimization (PSO) Support vector regression Torsional stress
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GB/T 7714 | Duan, Hao , Yin, Xiaojun , Kou, Hailiang et al. Regression prediction of hydrogen enriched compressed natural gas (HCNG) engine performance based on improved particle swarm optimization back propagation neural network method (IMPSO-BPNN) [J]. | Fuel , 2023 , 331 . |
MLA | Duan, Hao et al. "Regression prediction of hydrogen enriched compressed natural gas (HCNG) engine performance based on improved particle swarm optimization back propagation neural network method (IMPSO-BPNN)" . | Fuel 331 (2023) . |
APA | Duan, Hao , Yin, Xiaojun , Kou, Hailiang , Wang, Jinhua , Zeng, Ke , Ma, Fanhua . Regression prediction of hydrogen enriched compressed natural gas (HCNG) engine performance based on improved particle swarm optimization back propagation neural network method (IMPSO-BPNN) . | Fuel , 2023 , 331 . |
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Abstract :
Bolted flange joints are used to connect adjacent disks and drums in aero-engine rotors. The flange mating contact surfaces usually move relative to each other and deform when they are subjected to numerous combinations of loads during normal operation. Consequently, the local bending stiffness of the bolted flange joint is altered considerably affecting the overall rotor stiffness and therefore the rotor dynamics. This paper presents a study on the effect of the bending stiffness of bolted flange joints on the dynamic characteristics of an aero-engine rotor. A method to calculate the bending stiffness is proposed using an equivalent model based on an axial spring and bending beam stiffnesses. The relationship of the structure geometry, loading and assembly conditions of the bolted flange joints, and the bending stiffness loss are obtained. Furthermore, a dynamic model of an aero-engine high-pressure compressor rotor is developed using the transfer matrix method that incorporates the bending stiffness effect of the bolted flange joint. Based on this model, the influence of bending stiffness on the natural frequency and the steady-state response is discussed. The results show that the stiffness loss of bolted flange joint has a significant impact on the rotor dynamics. The structure geometry, loading, and assembly conditions can be used to control the dynamic response of aero-engine rotors. Copyright © 2022 by ASME.
Keyword :
Aircraft engines Dynamics Engines Flanges High pressure effects Stiffness Stiffness matrix Transfer matrix method
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GB/T 7714 | Zhu, Linbo , Pan, Hu , Yang, Yilong et al. EFFECT OF THE BENDING STIFFNESS OF BOLTED FLANGE JOINTS ON THE DYNAMICS OF AERO-ENGINE ROTORS [C] . 2022 . |
MLA | Zhu, Linbo et al. "EFFECT OF THE BENDING STIFFNESS OF BOLTED FLANGE JOINTS ON THE DYNAMICS OF AERO-ENGINE ROTORS" . (2022) . |
APA | Zhu, Linbo , Pan, Hu , Yang, Yilong , Bouzid, Abdel-Hakim , Hong, Jun . EFFECT OF THE BENDING STIFFNESS OF BOLTED FLANGE JOINTS ON THE DYNAMICS OF AERO-ENGINE ROTORS . (2022) . |
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Abstract :
Gear pump, as a main fuel pump, is a core component of aero-engine fuel system. Its safety performance directly affects the performance of the whole engine. In order to solve the problem that the mechanism of pressure pulsation of gear pump is not clear, the dynamic modeling of pressure pulsation during gear meshing is studied. Firstly, the dynamic model of pressure pulsation in the process of single gear meshing of gear pump was established by Euler method, and the variation rule of pressure pulsation in the process of single tooth engagement was analyzed. The correctness of the model was verified by comparing the simulation data and experimental data of pressure pulsation at the outlet volume of gear pump. Secondly, considering that the outlet volume fluid of the gear pump is turbulent, the pressure pulsation model at the outlet measuring point is proposed according to the periodic movement of the gear pump, and the modulation effect of the frequency on the pressure pulsation signal is discussed. Finally, the influence of different working conditions on pressure pulsation is discussed. With the increase of the workload, the frequency of pressure pulsation remains unchanged, but the amplitude of pressure pulsation increases. With the increase of rotating speed, the frequency of pressure pulsation increases and the amplitude of pressure pulsation decreases. © 2022 AAAS Press of Chinese Society of Aeronautics and Astronautics. All rights reserved.
Keyword :
Aircraft engines Engines Fuels Fuel systems Gear pumps Gears
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GB/T 7714 | Xu, Wengang , Wang, Zhiying , Sun, Chuang et al. Pressure pulsation mechanism of gear pump with frequency modulation [J]. | Acta Aeronautica et Astronautica Sinica , 2022 , 43 (9) . |
MLA | Xu, Wengang et al. "Pressure pulsation mechanism of gear pump with frequency modulation" . | Acta Aeronautica et Astronautica Sinica 43 . 9 (2022) . |
APA | Xu, Wengang , Wang, Zhiying , Sun, Chuang , Yan, Ruqiang , Chen, Xuefeng . Pressure pulsation mechanism of gear pump with frequency modulation . | Acta Aeronautica et Astronautica Sinica , 2022 , 43 (9) . |
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Abstract :
When designing infographics, general users usually struggle with getting desired color palettes using existing infographic authoring tools, which sometimes sacrifice customizability, require design expertise, or neglect the influence of elements' spatial arrangement. We propose a data-driven method that provides flexibility by considering users' preferences, lowers the expertise barrier via automation, and tailors suggested palettes to the spatial layout of elements. We build a recommendation engine by utilizing deep learning techniques to characterize good color design practices from data, and further develop InfoColorizer, a tool that allows users to obtain color palettes for their infographics in an interactive and dynamic manner. To validate our method, we conducted a comprehensive four-part evaluation, including case studies, a controlled user study, a survey study, and an interview study. The results indicate that InfoColorizer can provide compelling palette recommendations with adequate flexibility, allowing users to effectively obtain high-quality color design for input infographics with low effort.
Keyword :
Color palettes design Data visualization Deep learning Engines Image color analysis infographics Layout machine learning Tools Visualization visualization recommendation
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GB/T 7714 | Yuan, Lin-Ping , Zhou, Ziqi , Zhao, Jian et al. InfoColorizer: Interactive Recommendation of Color Palettes for Infographics [J]. | IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS , 2022 , 28 (12) : 4252-4266 . |
MLA | Yuan, Lin-Ping et al. "InfoColorizer: Interactive Recommendation of Color Palettes for Infographics" . | IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 28 . 12 (2022) : 4252-4266 . |
APA | Yuan, Lin-Ping , Zhou, Ziqi , Zhao, Jian , Guo, Yiqiu , Du, Fan , Qu, Huamin . InfoColorizer: Interactive Recommendation of Color Palettes for Infographics . | IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS , 2022 , 28 (12) , 4252-4266 . |
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Abstract :
The study presents an attempt for a simulation of the optimum expected to be obtained on the basis of the theoretical research for the best combination of the passengers being transported on board aircraft and the aircraft engine by-pass ratio. A few suppositions are accepted to simplify the conducted computational experimentations. The found solution is checked for the extremality with the help of variations. It reveals the maximum to the profit function. The illustrative examples are considered. The necessary diagrams are plotted. © 2022 IEEE.
Keyword :
Aircraft engines Air transportation Engines Profitability
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GB/T 7714 | Goncharenko, Andriy . Simulation on the Aircraft Engine By-Pass Ratio Optimization in Regards with the Number of the Passengers on Board [C] . 2022 : 294-297 . |
MLA | Goncharenko, Andriy . "Simulation on the Aircraft Engine By-Pass Ratio Optimization in Regards with the Number of the Passengers on Board" . (2022) : 294-297 . |
APA | Goncharenko, Andriy . Simulation on the Aircraft Engine By-Pass Ratio Optimization in Regards with the Number of the Passengers on Board . (2022) : 294-297 . |
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Abstract :
The concentricity of the aero-engine rotor is an important parameter to evaluate the quality of final assembly and directly affects the vibration characteristics, especially for high-speed rotation. The use of a bolted flange joint is the basic type of connection in aero-engine rotors. During the initial tightening of the bolts, large deformation usually occurs in the flange because its thickness is small. The deformation in the flange has a major impact on the concentricity and consequently the dynamic behavior of the aero-engine rotor. This paper proposes a novel stack-build assembly method to predict the concentricity of multi-stage rotors considering the deformation of the flange. The Small Displacement Torsor (SDT) method is employed to construct the mathematical model of part errors. The homogeneous coordinate transformation method is used to analyze the deviation propagation in the bolted flange joint of each stage part. A finite element (FE) model is built to obtain the deformation of the bolted flange joints by simulating the assembly process. The deformation of the flange is involved in the stack-build assembly model as an error matrix. Furthermore, the influence of the assembly process such as interference and preload, tightening sequence on the concentricity is investigated. The results show that bolted flange joints have a significant effect on concentricity, especially for the complex geometry at the flange interface. The developed approach is validated by experimental tests conducted on a multi-stage rotor. This study can provide guidance and enhance the dynamic performance of bolted joints for aero-engine rotors. Copyright © 2022 by ASME.
Keyword :
Aircraft engines Alignment Assembly Bolted joints Deformation Engines Flanges
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GB/T 7714 | Zhu, Linbo , Yang, Yilong , Huang, Hongwei et al. A NOVEL METHOD TO PREDICT THE CONCENTRICITY OF AERO-ENGINE ROTOR CONSIDERING THE ASSEMBLY PROCESS OF BOLTED FLANGE JOINTS [C] . 2022 . |
MLA | Zhu, Linbo et al. "A NOVEL METHOD TO PREDICT THE CONCENTRICITY OF AERO-ENGINE ROTOR CONSIDERING THE ASSEMBLY PROCESS OF BOLTED FLANGE JOINTS" . (2022) . |
APA | Zhu, Linbo , Yang, Yilong , Huang, Hongwei , Bouzid, Abdel-Hakim , Hong, Jun . A NOVEL METHOD TO PREDICT THE CONCENTRICITY OF AERO-ENGINE ROTOR CONSIDERING THE ASSEMBLY PROCESS OF BOLTED FLANGE JOINTS . (2022) . |
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Abstract :
EBCs were coated on the surfaces of SiC-CMCs to effectively isolate the engine corrosive environment and avoid rapid corrosion failure of the components, which become the key for the applications of SiC-CMCs to hot section components of gas turbine engines. However, interconnected pores were formed in coatings, causing rapid degradation in a combustion environment containing high-temperature water vapor and oxygen. The research progresses of the effects of EBCs materials properties, preparation technologies, and processing parameters on the pore structure were summarized. The effects of pore structure on the water vapor corrosion resistance was analyzed, and the research progresses of EBCs densification were summarized. Finally, future research on the preparation of dense EBCs to improve their water vapor resistance was prospected. © 2022, China Mechanical Engineering Magazine Office. All right reserved.
Keyword :
Ceramic matrix composites Corrosion resistance Corrosion resistant coatings Engines Pore structure Silicon Silicon carbide Water vapor
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GB/T 7714 | Dong, Lin , Yang, Guanjun , Zhang, Xiaofeng et al. Research Progresses of Dense Environmental Barrier Coatings with High Water Vapor Corrosion Resistance [J]. | China Mechanical Engineering , 2022 , 33 (12) : 1459-1467 . |
MLA | Dong, Lin et al. "Research Progresses of Dense Environmental Barrier Coatings with High Water Vapor Corrosion Resistance" . | China Mechanical Engineering 33 . 12 (2022) : 1459-1467 . |
APA | Dong, Lin , Yang, Guanjun , Zhang, Xiaofeng , Liu, Meijun , Zhou, Kesong , Li, Pu et al. Research Progresses of Dense Environmental Barrier Coatings with High Water Vapor Corrosion Resistance . | China Mechanical Engineering , 2022 , 33 (12) , 1459-1467 . |
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Abstract :
Mechanical structures with cavities such as auto rim and aero-engine casing are widely used in engineering. It is of great significance for their dynamic performance evaluation if one can measure the shape and deformation of the internal and external surfaces together. However, due to the narrow interior space and self-occlusion of complex structures, the conventional stereo-DIC unit is not applicable to impose the simultaneous measurement in the outer and inner areas. This paper is therefore concerned with a systematic solution for the issue. A reflection-assisted multi-view DIC system is configured, which consists of the stereo-DIC (SDIC) unit and the reflection-assisted stereo-DIC (RSDIC) unit. The design idea and selection essential of the RSDIC unit are stated. Subsequently, a correction model for reflection imaging is detailed. Close-range photogrammetry is specially adopted to compute the 3D global points. The extrinsic parameters of each DIC unit are estimated via the rear resection so that the individual reference frame can be transformed into a common coordinate system. Five experiments, including two tests of calibration accuracy, shape and deformation measurement accuracy, and applications in an aero-engine casing prototype, prove the precision and effectiveness of the proposed method. © 2022 Elsevier Ltd
Keyword :
Aircraft engines Deformation Engines Photogrammetry Stereo image processing
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GB/T 7714 | Ye, Meitu , Liang, Jin , Li, Leigang et al. Simultaneous measurement of external and internal surface shape and deformation based on photogrammetry and stereo-DIC [J]. | Optics and Lasers in Engineering , 2022 , 158 . |
MLA | Ye, Meitu et al. "Simultaneous measurement of external and internal surface shape and deformation based on photogrammetry and stereo-DIC" . | Optics and Lasers in Engineering 158 (2022) . |
APA | Ye, Meitu , Liang, Jin , Li, Leigang , Zong, Yulong , Guo, Jianying , Tang, Zhengzong et al. Simultaneous measurement of external and internal surface shape and deformation based on photogrammetry and stereo-DIC . | Optics and Lasers in Engineering , 2022 , 158 . |
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Abstract :
The spline coupling is widely used in aero-engines. Once the spline coupling fails, it will cause great damage to the engine. In this paper, the stability of a rotor with a spline coupling was studied. The internal damping instability model of the rotor with spline coupling is deduced, and the instability mechanism is explored. The stability boundary is analyzed by using the R-H criterion. The mechanism of rotor instability is analyzed by simulation. An experimental system of rotors with different structural parameters of spline coupling was built. The influence of the positioning surface clearance on the stability was analyzed. The modeling results show that the internal friction of the spline coupling will introduce additional damping and anti-symmetrical cross stiffness to the rotor, the additional damping will reduce the vibration response, and the anti-symmetrical cross stiffness will cause the rotor to become unstable. The simulation and experimental results show that the rotor system will not be unstable when the two positioning surfaces of the spline coupling are in an interference fit. When one of the positioning surfaces is a clearance fit and the other is an interference fit, the internal friction will cause the rotor to become unstable. The instability threshold speed is higher than the first-order critical speed. At the same time, due to the additional damping introduced by the sleeve tooth structure, there will be a transition stage of instability. At this time, the rotor will vibrate with sub-harmonic components, but the vibration amplitude of the rotor will decrease. When the two positioning surfaces are clearance fit, the rotor is unstable and the amplitude increases suddenly. The obtained instability characteristics of the rotor with spline coupling have important value for the instability fault diagnosis, and provide help for the stability control. © Published under licence by IOP Publishing Ltd.
Keyword :
Aircraft engines Damping Engines Splines Stability Stiffness
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GB/T 7714 | Wang, Tong , Wang, Yankai , Liu, Meiru et al. Stability Analysis of Rotor with a Spline Coupling [C] . 2022 . |
MLA | Wang, Tong et al. "Stability Analysis of Rotor with a Spline Coupling" . (2022) . |
APA | Wang, Tong , Wang, Yankai , Liu, Meiru , Zhong, Zhicai . Stability Analysis of Rotor with a Spline Coupling . (2022) . |
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Abstract :
This paper presents an electrocardiogram (ECG) processor for the detection of arrhythmia by using shared discrete wavelet transform (DWT) unit, optimized support vector machine (SVM) engine and multi-class classifier. The heartbeat detection (HD) and feature extraction (FE) can be both implemented in a shared DWT unit with extremely low resource overhead. An optimization method is proposed for the transformation of kernel and array scale reduction to lower the complexity of SVM engine. A compressed score matrix is exploited to reduce the computation burden of multi-class classifier. The chip is designed with a standard 40 nm CMOS process, which occupies area of 0.54 mm2 and consumes 10.8 nJ per heartbeat detection under 1.1 V supply voltage at 100 MHz operation frequency. The processor achieving 7-classification of arrhythmia can be used as real-time ECG monitoring for clinical applications with an average accuracy of 97.1%, sensitivity of 97.1% and specificity of 99.5%, respectively, which has better performances than other state-of-the-art works. © 2022 IEEE.
Keyword :
Biomedical signal processing Classification (of information) Discrete wavelet transforms Diseases Electrocardiograms Engines Feature extraction Signal reconstruction Support vector machines
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GB/T 7714 | Xing, Rui , Dong, Li , Xue, Zhongming et al. A 10.8 nJ/Detection ECG Processor Based on DWT and SVM for Real-Time Arrhythmia Detection [C] . 2022 . |
MLA | Xing, Rui et al. "A 10.8 nJ/Detection ECG Processor Based on DWT and SVM for Real-Time Arrhythmia Detection" . (2022) . |
APA | Xing, Rui , Dong, Li , Xue, Zhongming , Guo, Zhuoqi , Tang, Bingjun , Liu, Yanze et al. A 10.8 nJ/Detection ECG Processor Based on DWT and SVM for Real-Time Arrhythmia Detection . (2022) . |
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