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Natural Resources 2013年第5期4卷 395-403页

作者： Shiqiang Lai Zhengfang Liao College of Materials science and Engineering Chongqing University Chongqing China

In this paper, the basic theories of the self-excited Oscillation Pulsed Jet Nozzle (SEOPJN) invented by the authors are introduced. Then, some experimental results are shown. According to the results, using tricorn bits assembled the SEOPJN to drill oil well, the rate of penetration (ROP) increases by 8% - 77%, and the rate of the footage for tricorn bit increases by 6.7% - 44%. Although the test was conducted in the water, good result was got in nature gas transportation. The volume of gas transportation could be increased by the self-excited Oscillation Pulsed generator while the gas pressure drop could be decreased, since it significantly reduced the pressure loss during gas transportation.

关键词： self-excited Oscillation Pulsed Jet Nozzle Oil Well Natural Gas

Genetic Algorithm Based Performance Analysis of self excited Induction Generator

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Engineering（科研） 2011年第8期3卷 859-864页

作者： Hassan Ibrahim Mostafa Metwaly Department of Electrical and Computer Control Engineering Arab Academy for Science Technology and Maritime Transport

This paper investigates the effects of various parameters on the terminal voltage and frequency of self excited induction generator using genetic algorithm. The parameters considered are speed, capacitance, leakage reactance, stator and rotor resistances. Simulated results obtained using genetic algorithm facilitates in exploring the performance of self-excited induction generator. The paper henceforth establishes the application of user friendly genetic algorithm for studying the behaviour of self-excited induction.

关键词： self-excited Induction Generator Genetic Algorithm Toolbox Frequency Terminal Voltage

Large-eddy simulation and linear acoustic modeling of entropy mode oscillations in a model combustor with coolant injection

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Chinese Journal of Aeronautics 2018年第8期31卷 1691-1702页

作者： Man ZHANG An LIANG AECC Commercial Aireraft Engine Co. LTD Shanghai 200241 China

Lean-burn combustor is particularly susceptible to combustion instability and the unsteady heat release is usually considered as the excitation of the self-maintained thermoacoustic oscillations. The transverse coolant injection is widely used to reduce the temperature of burnt gas, but on the other hand, it will introduce temperature fluctuation inside the ***, it is necessary to consider the influence of the coolant injection on combustion instability, and evaluate its dynamic feature. In this paper, Large-Eddy Simulation（LES） of the self-excited pressure oscillations in a model combustor with coolant injection is carried out. The analysis of transient flow characteristics and the identification of the pressure modes confirm that one of the low frequency pressure oscillations is related to entropy fluctuations, which is known as rumble combustion instability. The LES results show that transient coolant injection is another excitation of temperature fluctuation other than unsteady combustion. The amplitude of the entropy mode oscillation increases with increasing coolant air mass whereas the change of its frequency is insignificant. According to the major feature of entropy wave oscillation caused by coolant injection, a compact coolant injection model is proposed and applied in the One Dimensional（1 D） Acoustic Network Method（ANM）. Key correlations used in the model match well with LES data in low frequency range. This means that the coolant injection model is a complex one reflecting the interaction of the fluctuating coolant mass, pressure and temperature. Finally, the combustion instability frequencies and modes predicted by acoustic network method are also in good agreement with LES results.

关键词： Acoustic wave Combustion instabilityCoolant injection Entropy LES Network method Rumble self-excited

Countermeasure Against Regenerative and Forced Chatter of Flexible Workpieces in Milling Processs Using Bi-directional Excitation

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第1期35卷 10-19页

作者： Nakano Yutaka De Silva Amal Dilanka Takahara Hiroki Akiyama Yu Department of Mechanical Engineering School of EngineeringTokyo Institute of Technology Department of Mechanical Sciences and Engineering Graduate School of Science and EngineeringTokyo Institute of Technology

A novel extended methodology for chatter suppression in milling process by applying external forced vibrations to the workpiece in two orthogonal directions which are the feed and cross-feed *** the regenerative and forced chatter suppression during the milling process of flexible workpieces are ***,the workpiece is subject to a sinusoidal periodic force in the feed direction to disrupt the regenerative ***,to minimize the forced chatter,the workpiece is subject to the periodic excitation force in cross-feed *** force is proportional to the magnitude of the estimated cutting force in cross-feed direction and has a phase opposite to the cutting force to minimize the vibration *** effectiveness of the proposed method is evaluated numerically and experimentally,for the spindle speed located in both the local minima and local maxima of the stability lobe *** numerical simulations indicate significant suppression effect in terms of vibration amplitudes,resulting in suppression of both the regenerative chatter and the forced *** were conducted by using a workpiece-mounted active stage composed of flexure hinges and driven by piezoelectric *** experimental results agree qualitatively with the numerical *** proposed method indicates a remarkable vibration reduction effect for both regenerative and forced chatters.

关键词： self-excited vibration vibration control regenerative chatter forced chatter milling

Fuzzy optimization of pneumatic half-floating slide ways

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Journal of Central South University 2008年第S2期15卷 377-382页

作者：李宇鹏高殿荣单彦霞张海青 School of Mechanical Engineering Yanshan University

Dynamic modeling was carried on by combining the dynamic of machinery with composite triology, and the critical condition in which the ways would not produce composite-friction self-excited vibration was obtained. The movement regularity and characteristic of the airflow in exhaust gas slit were analyzed, and the relationship between pressure lost and geometry parameters of exhaust gas slit was obtained. A dynamic model and a mathematical model were established for pneumatic half-floating slide ways by combining the dynamics of machinery with hydrokinetics. The objective function for the optimization of slide ways was established based on the fuzzy optimization theory. The membership function of fuzzy constraint was deduced, the fuzzy constraint limit was established by amplification coefficient method, and the optimal value was resolved by the multilevel fuzzy comprehensive evaluation method. By combining the internal penalty function method with the variable metric method, the fuzzy optimization design program of ways was designed based on the Matlab platform. The validation was carried on by an example, and ideal results of fuzzy optimization design of slide ways were obtained.

关键词： pneumatic half-floating slide ways composite-friction self-excited vibration dynamic modeling design parameter fuzzy optimization

Behavior an Induction Generator without and with a Voltage Regulator

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Smart Grid and Renewable Energy 2014年第9期5卷 207-219页

作者： M. L. Elhafyani S. Zouggar M. Benkaddour A. Aziz Department of Physics Faculty of Science University Mohammed 1 Oujda Morocco Laboratory of Electrical Engineering and Maintenance (LEEM) University Mohammed 1 Oujda Morocco

During the isolated use of a wind system, the output voltage of the self-excited induction generator depends on the variation characteristic of its parameters: the excitation condensers, the drive speed and the load. Therefore, the regulation of the tension appears to be of great interest. We focused on the use of an analogical regulator of tension, with the aim of controlling the tension at the exit of the self-excited induction generator. So we modelled, implanted and simulated a wind system (self-excited induction generator, converters (AC/DC, DC/DC) and load it) in the Orcad/Pspice environment. In the first time the behaviour of the asynchronous generator was analyzed when the load, the excitation capacitor and the drive speed vary in the absence of any form of regulation. This analysis was conducted with the aim of defining the limits of the machine exploitation. In the second time the functioning mode is controlled by an analogical control of tension. The results of simulation show the good performances of the system during the application of the proposed voltage regulator.

关键词： Wind Power self-excited Induction Generator Converters (Buck-Boost) Regulation

Simulation of Human Phonation with Vocal Nodules

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American Journal of Computational Mathematics 2011年第3期1卷 189-201页

作者： Shinji Deguchi Yuki Kawahara Department of Biomedical Engineering Tohoku University Department of Bioengineering and Robotics Tohoku University Graduate School of Natural Science and Technology Okayama University

The geometric and biomechanical properties of the larynx strongly influence voice quality and efficiency. A physical understanding of phonation natures in pathological conditions is important for predictions of how voice disorders can be treated using therapy and rehabilitation. Here, we present a continuum-based numerical model of phonation that considers complex fluid-structure interactions occurring in the airway. This model considers a three-dimensional geometry of vocal folds, muscle contractions, and viscoelastic properties to provide a realistic framework of phonation. The vocal fold motion is coupled to an unsteady compressible respiratory flow, allowing numerical simulations of normal and diseased phonations to derive clear relationships between actual laryngeal structures and model parameters such as muscle activity. As a pilot analysis of diseased phonation, we model vocal nodules, the mass lesions that can appear bilaterally on both sides of the vocal folds. Comparison of simulations with and without the nodules demonstrates how the lesions affect vocal fold motion, consequently restricting voice quality. Furthermore, we found that the minimum lung pressure required for voice production increases as nodules move closer to the center of the vocal fold. Thus, simulations using the developed model may provide essential insight into complex phonation phenomena and further elucidate the etiologic mechanisms of voice disorders.

关键词： Aerodynamics Flow–Structure Interaction self-excited Oscillation Phonation Vocal Fold Larynx Vocal Tract Speech Production Voice Production Vocal Nodules Vocal Cord Polyp Voice Disorder

Adaptive Fuzzy Sliding Mode Controller for Grid Interface Ocean Wave Energy Conversion

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Journal of Intelligent Learning Systems and Applications 2014年第2期6卷 53-69页

作者： Adel A. A. Elgammal Utilities Engineering Department The University of Trinidad and Tobago UTT Trinidad and Tobago West Indies

This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven self-excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.

关键词： Grid integration Wave Energy Conversion Systems self-excited Induction Generator (SEIG) Vector Control Genetic Algorithm (GA) Particle Swarm Optimization (PSO) Sliding Mode Control (SMC) Fuzzy Logic Control (FLC) Membership Function Tuning