International Journal of Applied Electromagnetics and Mechanics - Volume 46, issue 4

Authors: Zhang, Jian-Ping | Fang, Fang | Pan, Wei-Guo | Wu, Helen | Ren, Jian-Xing

Article Type: Research Article

Abstract: In order to study PM2.5 removal performance under multi-field coupling and applied magnetic field, a mathematical model was proposed to analyze the interaction between fluid flow field, electro- magnetic field and particle dynamic field. The computational fluid dynamics method and FLUENT were employed to numerically simulate the PM2.5 removal performance in a Wire-pipe ESP. The effects of magnetic field on PM2.5 collection efficiency at different working voltages and gas velocities were discussed. The results indicate that …the influence of applied magnetic field on PM2.5 collection in the wire-pipe ESP becomes more obvious with the increase of the particle diameter, and the increment of PM2.5 grade efficiency decreases with the increasing magnetic flux density in a certain range of particle diameters. Furthermore, the effect of magnetic field on PM2.5 collection increases with a decrease of working voltage or an increase of gas velocity, and PM2.5 collection efficiency declines at the same time. At a lower flue gas velocity, the impact of flue gas velocity on PM2.5 overall efficiency is more significant than that of applied magnetic field. Show more

Keywords: Wire-pipe ESP, PM2.5, collection efficiency, applied magnetic field, multi-field coupling

DOI: 10.3233/JAE-141970

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 739-750, 2014

Authors: Pang, Yan | Xia, Hao

Article Type: Research Article

Abstract: A Free Piston Energy Converter (FPEC) is a combination of a linear combustion engine and a linear electrical machine. It is a potential technology for series hybrid vehicles, as well as stationary power generation applications. In a free piston energy converter, the piston is not connected to a crank-shaft. Instead, the piston movement is "free" and controlled by a linear hydraulic or electric machine. The major advantages of such a design over the conventional ones are …the simpler engine layout and much improved conversion efficiency. Unlike other traditional modeling method, in this paper, the free piston converter is modeled as a hybrid automaton. A hierarchical hybrid controller is designed based on this model. The hybrid controller includes a discrete controller which is in charge of switching actions and a continuous controller which compute the electro-magnetic force. High-fidelity simulation results are provided to illustrate the applicability and performance of developed control law. Show more

Keywords: Hybrid systems, control, electro-magnetic force, free piston energy converter

DOI: 10.3233/JAE-141971

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 751-762, 2014

Authors: Tang, Mingsheng | Zou, Huiming | Xu, Hongbo | Shao, Shuangquan | Tian, Changqing

Article Type: Research Article

Abstract: The stroke and natural frequency are key controlling quantities for linear compressor controller. This paper proposes a phasor algorithm for the linear compress stroke and natural frequency calculation. The phasor algorithm employs vectors to express the voltage, current and velocity respectively for the calculation in frequency domain. A test bench has been installed, and the feasibility of phasor algorithm is verified with the linear compressor load changing. The relative deviation of the calculated stroke can be …achieved within ± 3% experimental results at 0.4 MPa, 0.5 MPa and 0.6 MPa discharge pressure respectively. The calculated results shows that the computation time of phasor algorithm is one-third shorter than that of time domain algorithm, which means it is possible to employ relatively low energy consumption and low cost hard ware. The calculation natural frequency decreases with the stroke increases at 0.4 MPa, 0.5 MPa and 0.6 MPa discharge pressure respectively, and the tested motor efficiency reaches a maximum when the calculated natural frequency equals to the operating frequency. Show more

Keywords: Linear compressor control, stroke estimation, natural frequency estimation, phasor algorithm

DOI: 10.3233/JAE-141972

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 763-774, 2014

Authors: Cheng, Qiang | Zhang, Zhen-Dong | Guo, Hui | Xie, Nai-Liu

Article Type: Research Article

Abstract: The GDI (Gasoline Direct Injection) injector is influenced by electro-magnetic-thermal coupling, and has strong nonlinearity and coupling. Temperature rise greatly impacts the performance of the GDI injector and makes the ECU of the engine difficult to control fuel injection quantity accurately. According to the coupling relationship of electric, magnetic and thermal subsystems of the GDI injector, the physical model of coupled process was established. The energy loss and transformation of the GDI injector in work …process was explored, and revealed that the energy loss in electromagnetic conversion was a key factor to cause the GDI injector temperature rise. The energy loss coming from electromagnetic conversion was regarded as heat source. The temperature field of the GDI injector contains heat conduction and thermal radiation was analyzed based on the finite element theories. By using the ANSYS software to simulate multiple physical fields of the GDI injector, and then experiment method to verify the simulation results, distribution characteristics of temperature field and variations of temperature rise effect on the performance of the GDI injector was analyzed. The results show that, higher temperature rise is concentrated on coil and core part and with the higher temperature rise the response time of the GDI injector get longer, the fuel injection quantity becomes less. The value and pulse width of the holding current I have great impact on the GDI injector performance and temperature rise. Show more

Keywords: GDI injector, temperature rise, electric-magnetic-thermal coupling, finite element simulation, dynamic response

DOI: 10.3233/JAE-141973

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 775-792, 2014

Authors: Kaikaa, M.Y.

Article Type: Research Article

Abstract: In this paper, a precise approach is proposed to detect DE in induction motors under unbalanced voltages. To achieve this goal, one essential problem is dealt with: The frequencies of the components caused by the DE in the stator current spectrum are similar to some of the frequencies introduced by the unbalanced voltages. Thus, the present paper attempts to explain, analytically, experimentally and by simulation, the generation process of all frequency components that are a function …of the unbalanced voltages and the DE. For that reason, a detailed analytical study for three-phase induction motor working with DE is performed. First, an analytical expression for the mutual inductances between stator phases and rotor loops under DE is derived using mixture of winding function and Fourier series approach. Then, both theoretical and simulation studies are presented in order to show how the stator current is influenced by the simultaneous presence of DE eccentricity and unbalance supply voltages. Finally, experimental results have been presented to validate the analytical and simulation results. Show more

Keywords: Dynamic eccentricity, unbalanced voltages, induction motor, fault diagnosis, rotor slot harmonics

DOI: 10.3233/JAE-141974

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 793-808, 2014

Authors: Afrand, Masoud | Farahat, Said | Nezhad, Alireza Hossein | Ali Sheikhzadeh, Ghanbar | Sarhaddi, Faramarz

Article Type: Research Article

Abstract: In the present paper, numerical analysis of an electrically conducting fluid under the influence of a magnetic field in an inclined cylindrical annulus is presented. The inner and outer walls are kept at constant temperatures, and the top and bottom walls are assumed to be adiabatic. The numerical method used to solve the nonlinear governing equations of the problem is finite volume scheme. The computational results reveal that the effect of transverse magnetic field is more …significant than that of the axial magnetic field on the average Nusselt number. Also, it is found that when the magnetic field is perpendicular to the axis of annulus, the average Nusselt number decreases from 7.8 to 4.7 with an increase in Ha from 0 to 60. Show more

Keywords: Tilted cylindrical annulus, natural convection control, various magnetic fields, electrical potential, 3D numerical simulation

DOI: 10.3233/JAE-141975

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 809-821, 2014

Authors: Lv, Chunfeng | Liu, Weiwen | Jiang, Yingying | Zhao, Hui

Article Type: Research Article

Abstract: Analytical method for eddy current evaluation is an attractive field of learning the concept of electromagnetic phenomena. This paper proposes an analytical approach to a transverse eddy current displacement sensor with a rectangular testing coil. Solving domain in the Cartesian coordinate system is limited to finite extents through imposing artificial boundaries at x and y axis, and solutions to the electromagnetic field are expressed as double series. Complete closed-form expressions based on second order vector potential …for the electromagnetic field in each region can be obtained from the continuity conditions at the interfaces by mode matching. Closed-form expressions of the eddy current density as well as coil impedance related to the transverse displacement can thus be derived, and the calculated results show good agreement with the experimental results. Show more

Keywords: Analytical modelling, eddy current, transverse displacement, rectangular coil

DOI: 10.3233/JAE-130060

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 823-834, 2014

Authors: Zhang, Chao | Ji, Hongli | Qiu, Jinhao | Wu, Yucheng | Hu, Ning

Article Type: Research Article

Abstract: This study presents a novel imaging method in passive sensing structural health monitoring (SHM), for locating impact damage in real-time on a plate-like structure. So far, many imaging methods have already been applied in active sensing SHM to locate the damages. However, seldom of the imaging methods can be directly used to locate the impact in passive sensing SHM. In order to avoid solving the hyperstatic hyperbolic equations and generate an informative image for locating the …impact damage, the proposed method combines the imaging method with probability calculation. Moreover, to demonstrate the feasibility of the proposed method, the experimental results are presented and analyzed. From the results, the proposed method shows an interesting phenomenon that the accuracy of the impact localization depends on the impact position. Finally, a detailed analysis of the method accuracy is discussed. Show more

Keywords: Structural health monitoring, impact localization, imaging method

DOI: 10.3233/JAE-140092

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 835-844, 2014

Authors: Su, Y.H. | Liu, Y.P. | Vasic, D. | Costa, F. | Wu, W.J. | Lee, C.K.

Article Type: Research Article

Abstract: In this paper, we propose a new design of a piezoelectric transformer (PT) for low-profile DC/DC converter applications, which increases the output power by using heat transfer equipment. We examined several parameters, which allow us to produce a piezoelectric transformer with optimal efficiency. Instead of looking at the typically optimal loading condition of the PT, we consider the influence of the temperature rise on losses. When the vibration velocity is too large, the piezoelectric transformer generates …heat unstably until it cracks. By maintaining the vibration mode and limiting the heat produced by the PT, this design can enhance the power capacities of the PT and thus increase the output power of the DC/DC converter. A finite element analysis (FEA) approach with COMSOL Multiphysics was made to predict PT's working temperature. A theoretical-phenomenological model was also developed to explain the relationship between the equivalent losses resistances and the input voltage at different temperatures. It will be shown that the vibration velocity as well as the heat generation increases the losses. A large vibration velocity and generated heat may cause the temperature feedback loop to enter into an unstable state. We began by modeling a piezoelectric transformer in a DC/DC converter configuration in order to determine the design constraints and variables such as the maximum mechanical current, the temperature distribution, the PT geometrical configuration and the energy balance. In our design, the PT power capacity increases 3 times (i.e. from 4.54 W to 13.29 W) at specific temperature and the effects of the different cooling methods of the system were verified. The study comprises of a theoretical part and experimental proof-of-concept demonstration of the proposed design method. Show more

Keywords: Piezoelectric transformer, power capacity, power density

DOI: 10.3233/JAE-140093

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 845-857, 2014

Authors: Lin, Xiujuan | Chen, Haiyan | Jiang, Chao | Zhou, Kechao | Zhang, Dou

Article Type: Research Article

Abstract: Finite element analysis was performed on the representative volume element of piezoelectric elements with interdigitated electrodes (IDEs). The variations of piezoelectric material properties during poling were considered in the analysis. The numerical results of models with different piezoelectric polarization states were compared with the result given by the so called uniform field model. Though different optimum electrode finger widths were obtained for different models, narrower electrode finger could enhance the actuation performance. …The models indicated the stress concentrated at the edges of the finger electrode. Wider electrode finger would be beneficial for reducing the risk of material failure. The model with two different polarization states could be used to predict the strain and stress of MFCs with wider electrode finger to minimize the computational complexity. The modeling approach developed in this study allowed for a better understanding on the overall effects in piezoelectric materials with IDE structures. Show more

Keywords: Finite element analysis, electrode finger width, polarization state, strain, stress

DOI: 10.3233/JAE-140094

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 859-866, 2014