Pub Date : 2022-09-30DOI: 10.4283/jmag.2022.27.3.233
T. T. Hoang, S. Rhim, S. C. Hong
{"title":"A First-principles Study on Half-metallicity of LiCrSb/InSb Hybrid System","authors":"T. T. Hoang, S. Rhim, S. C. Hong","doi":"10.4283/jmag.2022.27.3.233","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.3.233","url":null,"abstract":"","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83033618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-30DOI: 10.4283/jmag.2022.27.3.238
Seungha Yoon
{"title":"Inverse Magnetostrictive Effect in NixFe1-x (1≤ x ≤0.8) Thin Films Deposited on a Polypropylene Substrate","authors":"Seungha Yoon","doi":"10.4283/jmag.2022.27.3.238","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.3.238","url":null,"abstract":"","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88142265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-30DOI: 10.4283/jmag.2022.27.2.172
Chun‐Chih Liao, Xun Zhou, P. Jiang, Z. Zeng, Lianghua Que
The ability to improve the coercivity of sintered Nd-Fe-B diffused by Dy-Al-Cu alloy derived from electrolysis in a fluoride salt-oxide system was evaluated. The results show that with the increase in heat treatment time, the coercivity of the magnet firstly increased and then decreased. Holding at 900 ℃ for 4 h, tempering at low temperature for 3 h at 550 ℃, the coercivity of GBDPed magnet increased by 44.34 %, the remanence decreased by 1.26 %, the Dy-rich shell phase was recognizable, and the Nd-rich phase evenly distributed. Electron microscope analysis showed that when the GBDP time was longer than 4h, the diffusion of Dy from the shell phase to the matrix phase dominated, decreasing the coercivity with the increase in the diffusion time. The increase of Fe content in the grain boundary phase enhanced the exchange coupling between grains, which also reduced the coercivity of the GBDPed magnet. The infiltration of the matrix phase by excessive Dy and deterioration of (00L) texture of Nd-Fe-B resulted in the reduction of the remanence and the maximum energy product.
{"title":"Magnetic Properties and Microstructure of DyAlCu-diffusion Sintered Nd-Fe-B Magnets","authors":"Chun‐Chih Liao, Xun Zhou, P. Jiang, Z. Zeng, Lianghua Que","doi":"10.4283/jmag.2022.27.2.172","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.2.172","url":null,"abstract":"The ability to improve the coercivity of sintered Nd-Fe-B diffused by Dy-Al-Cu alloy derived from electrolysis in a fluoride salt-oxide system was evaluated. The results show that with the increase in heat treatment time, the coercivity of the magnet firstly increased and then decreased. Holding at 900 ℃ for 4 h, tempering at low temperature for 3 h at 550 ℃, the coercivity of GBDPed magnet increased by 44.34 %, the remanence decreased by 1.26 %, the Dy-rich shell phase was recognizable, and the Nd-rich phase evenly distributed. Electron microscope analysis showed that when the GBDP time was longer than 4h, the diffusion of Dy from the shell phase to the matrix phase dominated, decreasing the coercivity with the increase in the diffusion time. The increase of Fe content in the grain boundary phase enhanced the exchange coupling between grains, which also reduced the coercivity of the GBDPed magnet. The infiltration of the matrix phase by excessive Dy and deterioration of (00L) texture of Nd-Fe-B resulted in the reduction of the remanence and the maximum energy product.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75497007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-30DOI: 10.4283/jmag.2022.27.2.201
E. Goo
To investigate the optimum flip angle that can enhance image quality, SNR (signal to noise ratio), and CNR (contrast to noise ratio), comparing the images obtained, applying flip angles, 11°, 14°, 17°, 20°, and 23° in get-ting Liver Hepatobiliary Phase image using 3D VANE XD(3D Multivane mDixon, Philips Healthcare) technique. Experiments were conducted on a total of 30 outpatients and inpatients to our hospital (HCC:10, Metastasis:10, Abscess:10). As for the equipment used in the experiments, Philips Ingenia 3.0T CX was used, and all parameters other than the flip angle were set the same to conduct the tests. As for the image analysis method, using the Image-J program (National Institutes of Health and LOCI), the SNR of the liver, kidney, and pancreas obtained from the images by flip angle before the contrast medium injection and the CNR between the lesion and the normal tissue after the contrast medium injection were measured to conduct comparative analysis. As a result of a comparison of images before and after the contrast medium injection by disease, when the flip angle of 17° was applied, SNR and CNR were measured higher than in the images of other flip angles (p<0.05). In the comparisons of the images taken before and after the injection of contrast medium by disease, when a flip angle of 17° was applied, the SNR before contrast medium injection was 28-29 % higher, and the SNR after the injection of contrast medium was 11 % up to 49 % higher than that at other flip angles. There was a difference in CNR before contrast medium injection of 30-43 % and CNR after contrast medium injection of 58-68 %. The measured value increased up to 17° and then decreased after that. Additionally, in the qualitative evaluation, Lesion Conspicuity (p=0.003), Image Artifact (p=0.0001), Lesion Delineation (p=0.0002), and Vascular Anatomy (p=0.0002) received the most excellent evaluations at 17°. In conclusion, in this study, the flip angle of 17° provided the highest SNR and CNR values when the tests were conducted using the free breath hold technique, 3D VANE XD Sequence. Thus, in liver MRI protocol tests, the overall diagnostic information was provided, including hypervascular tumor.
为了研究可以提高图像质量、信噪比(SNR)和噪比(CNR)的最佳翻转角度，比较获得的图像，使用3D VANE XD(3D Multivane mDixon, Philips Healthcare)技术，应用11°、14°、17°、20°和23°翻转角度获得肝脏肝胆相图像。实验共选取我院门诊和住院患者30例(HCC:10例，转移:10例，脓肿:10例)。实验使用的设备为Philips Ingenia 3.0T CX，除翻转角度外其他参数设置相同，进行实验。在图像分析方法上，使用image - j程序(National Institutes of Health and LOCI)，测量注射造影剂前通过翻转角度获得的图像中肝脏、肾脏和胰腺的信噪比，以及注射造影剂后病变与正常组织的CNR，进行对比分析。对比疾病注射造影剂前后的图像，采用17°翻转角度时，SNR和CNR均高于其他翻转角度的图像(p<0.05)。对比疾病注射造影剂前后的图像，当翻转角度为17°时，注射造影剂前的信噪比比其他翻转角度高28 ~ 29%，注射造影剂后的信噪比比其他翻转角度高11% ~ 49%。注射造影剂前的CNR为30 ~ 43%，注射造影剂后的CNR为58 ~ 68%。测量值在达到17°时增大，之后减小。此外，在定性评价中，病变显著性(p=0.003)、图像伪影(p=0.0001)、病变描绘(p=0.0002)和血管解剖(p=0.0002)在17°时获得了最好的评价。综上所述，在本研究中，当使用自由屏气技术3D VANE XD序列进行测试时，17°的翻转角度提供了最高的信噪比和CNR值。因此，在肝脏MRI方案测试中，提供了包括高血管肿瘤在内的总体诊断信息。
{"title":"Estimation of Optimum Flip Angle using 3D VANE XD Technique: Focused on Pre-Contrast and Hepatobiliary Phase","authors":"E. Goo","doi":"10.4283/jmag.2022.27.2.201","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.2.201","url":null,"abstract":"To investigate the optimum flip angle that can enhance image quality, SNR (signal to noise ratio), and CNR (contrast to noise ratio), comparing the images obtained, applying flip angles, 11°, 14°, 17°, 20°, and 23° in get-ting Liver Hepatobiliary Phase image using 3D VANE XD(3D Multivane mDixon, Philips Healthcare) technique. Experiments were conducted on a total of 30 outpatients and inpatients to our hospital (HCC:10, Metastasis:10, Abscess:10). As for the equipment used in the experiments, Philips Ingenia 3.0T CX was used, and all parameters other than the flip angle were set the same to conduct the tests. As for the image analysis method, using the Image-J program (National Institutes of Health and LOCI), the SNR of the liver, kidney, and pancreas obtained from the images by flip angle before the contrast medium injection and the CNR between the lesion and the normal tissue after the contrast medium injection were measured to conduct comparative analysis. As a result of a comparison of images before and after the contrast medium injection by disease, when the flip angle of 17° was applied, SNR and CNR were measured higher than in the images of other flip angles (p<0.05). In the comparisons of the images taken before and after the injection of contrast medium by disease, when a flip angle of 17° was applied, the SNR before contrast medium injection was 28-29 % higher, and the SNR after the injection of contrast medium was 11 % up to 49 % higher than that at other flip angles. There was a difference in CNR before contrast medium injection of 30-43 % and CNR after contrast medium injection of 58-68 %. The measured value increased up to 17° and then decreased after that. Additionally, in the qualitative evaluation, Lesion Conspicuity (p=0.003), Image Artifact (p=0.0001), Lesion Delineation (p=0.0002), and Vascular Anatomy (p=0.0002) received the most excellent evaluations at 17°. In conclusion, in this study, the flip angle of 17° provided the highest SNR and CNR values when the tests were conducted using the free breath hold technique, 3D VANE XD Sequence. Thus, in liver MRI protocol tests, the overall diagnostic information was provided, including hypervascular tumor.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77959889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-30DOI: 10.4283/jmag.2022.27.2.223
A. Majeed, A. Zeeshan, A. Shaheen, M. Alhodaly, F. Noori
Power generators, Hall accelerators, and flight MHD all require high levels of Hall current. The influence of Hall current and viscous dissipation on time-independent hydro-magnetic mixed convective radiative flow across a porous heated surface has thus been investigated using numerical computing and mathematical mod-eling in the current study. The fluid is electrically conducted and varies exponentially. It is assumed that the wall temperature and elongation rate will vary with specific exponential shapes. A solid uniform magnetic field B 0 is employed normally to the surface. The mathematical model of PDEs for incompressible flow is transformed into ODE by applying a numerical technique based on a finite-difference structure which includes a three-stage Lobatto IIIa scheme with the help of MATLAB. The obtained solution depends on the convergence constraints involving the radiation parameter R , magnetic parameter M , porosity parameter , Hall parameter m , buoyancy parameter ε , temperature distribution parameter a , Eckert number E c , Prandtl number P r , and convective term bh . Graphs of the velocity and temperature profiles are explained via pertinent parameters. Skin friction factor, and Nusselt number are also evaluated and presented graphically and in tabular form. Results clarify that temperature profile reduces by increasing values of temperature distribution parameter whereas opposite behavior is noted for positive values of the buoyancy parameter.
{"title":"Hall Current and Viscous Dissipation Impact on MHD Mixed Convection Flow towards a Porous Exponentially Surface with its Engineering Applications","authors":"A. Majeed, A. Zeeshan, A. Shaheen, M. Alhodaly, F. Noori","doi":"10.4283/jmag.2022.27.2.223","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.2.223","url":null,"abstract":"Power generators, Hall accelerators, and flight MHD all require high levels of Hall current. The influence of Hall current and viscous dissipation on time-independent hydro-magnetic mixed convective radiative flow across a porous heated surface has thus been investigated using numerical computing and mathematical mod-eling in the current study. The fluid is electrically conducted and varies exponentially. It is assumed that the wall temperature and elongation rate will vary with specific exponential shapes. A solid uniform magnetic field B 0 is employed normally to the surface. The mathematical model of PDEs for incompressible flow is transformed into ODE by applying a numerical technique based on a finite-difference structure which includes a three-stage Lobatto IIIa scheme with the help of MATLAB. The obtained solution depends on the convergence constraints involving the radiation parameter R , magnetic parameter M , porosity parameter , Hall parameter m , buoyancy parameter ε , temperature distribution parameter a , Eckert number E c , Prandtl number P r , and convective term bh . Graphs of the velocity and temperature profiles are explained via pertinent parameters. Skin friction factor, and Nusselt number are also evaluated and presented graphically and in tabular form. Results clarify that temperature profile reduces by increasing values of temperature distribution parameter whereas opposite behavior is noted for positive values of the buoyancy parameter.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83477112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-30DOI: 10.4283/jmag.2022.27.2.179
Yesudasu Bammidi, C. Angani, K. Rao, M. Kishore, G. Podagatlapalli, S. Sreedhar
Failures in the industrial components are unavoidable due to material degradation from various sources, thus continuous monitoring and timely inspection is mandatory for structural safety. In the present study, the recently developed Transient Eddy Current Oscillations (TECO) method is used to detect wall-thinning in a stainless-steel plate. Unlike the conventional Eddy Current Testing impedance plane data a new interpretation method has been implemented to identify a thickness variation using the S-domain parameters. Furthermore, time and frequency spectral features are analysed to get more insight into the results. The decay time and the resonant frequency are the basis for the discussion to assess the wall thickness.
{"title":"Study of Change in Stainless Steel Plate Thickness using S-Domain Parameters Derived from Transient Eddy Current Oscillations Method","authors":"Yesudasu Bammidi, C. Angani, K. Rao, M. Kishore, G. Podagatlapalli, S. Sreedhar","doi":"10.4283/jmag.2022.27.2.179","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.2.179","url":null,"abstract":"Failures in the industrial components are unavoidable due to material degradation from various sources, thus continuous monitoring and timely inspection is mandatory for structural safety. In the present study, the recently developed Transient Eddy Current Oscillations (TECO) method is used to detect wall-thinning in a stainless-steel plate. Unlike the conventional Eddy Current Testing impedance plane data a new interpretation method has been implemented to identify a thickness variation using the S-domain parameters. Furthermore, time and frequency spectral features are analysed to get more insight into the results. The decay time and the resonant frequency are the basis for the discussion to assess the wall thickness.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84348784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-30DOI: 10.4283/jmag.2022.27.2.147
Jangho Seo
A new winding structure for modular dual 3-phase permanent magnet machine, which makes it possible to reduce mutual coupling between two-winding sets of inverters and interference between phases that belong to the same inverter has been proposed in this study. The modular dual 3-phase system with overlapping winding technique has been widely employed in large-scale machine applications such as wind power production; how-ever, its drawbacks include large torque ripple, long end-winding, and large magnetic mutual interference. To address these problems, a new modular dual 3-phase winding can be achieved by replacing adjacent redundant coils in one of the same phase coils with nonoverlapping winding. For clarity, three dual 3-phase machines are selected to examine their differences. The first is 32-poles/96-slots adopting a conventional overlapping modular winding ('Conv-1'), the second is 32-poles/36-slots based on the conventional nonoverlapping winding ('Conv-2'), and the other is 32-poles/36-slots adopting the proposed modular winding configuration ('Pro-posed'). The validity of the proposed structure is confirmed from simulation results obtained using finite element analysis.
{"title":"Comparison of Electromagnetic Performance according to Winding Configuration for Modular Dual 3-Phase Permanent Magnet Machines","authors":"Jangho Seo","doi":"10.4283/jmag.2022.27.2.147","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.2.147","url":null,"abstract":"A new winding structure for modular dual 3-phase permanent magnet machine, which makes it possible to reduce mutual coupling between two-winding sets of inverters and interference between phases that belong to the same inverter has been proposed in this study. The modular dual 3-phase system with overlapping winding technique has been widely employed in large-scale machine applications such as wind power production; how-ever, its drawbacks include large torque ripple, long end-winding, and large magnetic mutual interference. To address these problems, a new modular dual 3-phase winding can be achieved by replacing adjacent redundant coils in one of the same phase coils with nonoverlapping winding. For clarity, three dual 3-phase machines are selected to examine their differences. The first is 32-poles/96-slots adopting a conventional overlapping modular winding ('Conv-1'), the second is 32-poles/36-slots based on the conventional nonoverlapping winding ('Conv-2'), and the other is 32-poles/36-slots adopting the proposed modular winding configuration ('Pro-posed'). The validity of the proposed structure is confirmed from simulation results obtained using finite element analysis.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81783207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aiming to solve the problem of magnetorheological transmission heat dissipation, a novel magnetorheological fluid transmission device is designed, and the torque of the device is analyzed. Based on electromagnetic the-ory, the magnetic circuit of the device is designed. The finite element method is used to simulate the magnetic field of the measurement device. Results show that the working magnetic induction can reach 0.5 T when the current is 1.6 A, which can meet design requirements. The magnetic induction intensity in the working space increases with the increase of the excitation current and permeability of the magnetic conductive material; decreases with the increase of the size of the working space; and increases with the increase of the size of the magnetic ring. The magnetic induction intensity in the working area is DT4C, 20 steel, and 45 steel from strong to weak. The experimental results are consistent with the simulation.
{"title":"Research on Magnetic Field of Multistage Counter Roll Magnetorheological Fluid Transmission Device","authors":"Xiangfan Wu, Yangyang Guo, Zu-zhi Tian, Fangwei Xie, Yujie Tang","doi":"10.4283/jmag.2022.27.2.132","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.2.132","url":null,"abstract":"Aiming to solve the problem of magnetorheological transmission heat dissipation, a novel magnetorheological fluid transmission device is designed, and the torque of the device is analyzed. Based on electromagnetic the-ory, the magnetic circuit of the device is designed. The finite element method is used to simulate the magnetic field of the measurement device. Results show that the working magnetic induction can reach 0.5 T when the current is 1.6 A, which can meet design requirements. The magnetic induction intensity in the working space increases with the increase of the excitation current and permeability of the magnetic conductive material; decreases with the increase of the size of the working space; and increases with the increase of the size of the magnetic ring. The magnetic induction intensity in the working area is DT4C, 20 steel, and 45 steel from strong to weak. The experimental results are consistent with the simulation.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89194375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-30DOI: 10.4283/jmag.2022.27.2.164
Fuxiang Hao, An-le Mu
In order to better solve the problem of air leakage during compressor operation, based on the converging stepped magnetic fluid seal structure, the L 16 (4 4 ) orthogonal test design and the numerical simulation of the finite element method are combined to optimize the sealing structure. Four factors, four levels and the corresponding orthogonal table are selected in this paper. The simulation results of each test are calculated and range values are studied. Finally, sealing pressure capability of the structure before and after optimization are calculated and compared. The results show that under the conditions of different axial and radial sealing gaps, the sealing pressure capability of converging stepped magnetic fluid seal structure has been significantly improved after orthogonal optimization, especially when the radial sealing gap is relatively small. The maximum pressure capability can be improved by about 11 %, which fully proves the effectiveness of orthogonal optimization. At the same time, the research results can also provide references for the application of other rotary sealing conditions.
{"title":"Orthogonal Optimization Design and Finite Element Analysis of Converging Stepped Magnetic Fluid Seal","authors":"Fuxiang Hao, An-le Mu","doi":"10.4283/jmag.2022.27.2.164","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.2.164","url":null,"abstract":"In order to better solve the problem of air leakage during compressor operation, based on the converging stepped magnetic fluid seal structure, the L 16 (4 4 ) orthogonal test design and the numerical simulation of the finite element method are combined to optimize the sealing structure. Four factors, four levels and the corresponding orthogonal table are selected in this paper. The simulation results of each test are calculated and range values are studied. Finally, sealing pressure capability of the structure before and after optimization are calculated and compared. The results show that under the conditions of different axial and radial sealing gaps, the sealing pressure capability of converging stepped magnetic fluid seal structure has been significantly improved after orthogonal optimization, especially when the radial sealing gap is relatively small. The maximum pressure capability can be improved by about 11 %, which fully proves the effectiveness of orthogonal optimization. At the same time, the research results can also provide references for the application of other rotary sealing conditions.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88906968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-30DOI: 10.4283/jmag.2022.27.2.123
Gyeonghwan Yun, Yongha Choo, Changhwan Kim, Cheewoo Lee
This paper presents the new shape of a rotor bar improving the starting performances in a double-cage induction motor (IM). The rotor bar of a doble-cage IM is composed of a working bar, neck, and starting bar and each part has different effects on the characteristics of a motor. In this paper, it is confirmed that a starting bar has a dominant effect on the starting performances. The shape of a starting bar is designed by using the two ratios of the depth to width and the lower to upper width, respectively. The starting performances are closely analyzed by estimating the reactance and resistance of a rotor bar with respect to the depth through multi-layer method and FEA. Finally, by applying both the ratios to the starting bar, their mutual influence is scrutinized by using a response surface methodology and three models satisfying both starting torque and current aimed in this paper is proposed.
{"title":"Investigation of Starting Characteristics with respect to Starting-Bar Shape in a Double-Cage Induction Motor","authors":"Gyeonghwan Yun, Yongha Choo, Changhwan Kim, Cheewoo Lee","doi":"10.4283/jmag.2022.27.2.123","DOIUrl":"https://doi.org/10.4283/jmag.2022.27.2.123","url":null,"abstract":"This paper presents the new shape of a rotor bar improving the starting performances in a double-cage induction motor (IM). The rotor bar of a doble-cage IM is composed of a working bar, neck, and starting bar and each part has different effects on the characteristics of a motor. In this paper, it is confirmed that a starting bar has a dominant effect on the starting performances. The shape of a starting bar is designed by using the two ratios of the depth to width and the lower to upper width, respectively. The starting performances are closely analyzed by estimating the reactance and resistance of a rotor bar with respect to the depth through multi-layer method and FEA. Finally, by applying both the ratios to the starting bar, their mutual influence is scrutinized by using a response surface methodology and three models satisfying both starting torque and current aimed in this paper is proposed.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76822185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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