Transactions of the Japan Society of Mechanical Engineers. B最新文献_第2页

An Onset of Micromixing Flow Utilizing Marangoni Force 利用马兰戈尼力的微混合流的开始

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2013-07-15 DOI: 10.1299/KIKAIB.79.888

Takashi Yamada, N. Ono

引用次数: 2

Effects of tip clearance flow on rotating stall inception process in an axial compressor rotor 叶尖间隙流动对轴流压气机转子旋转失速形成过程的影响

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2013-07-15 DOI: 10.1299/KIKAIB.79.900

Kazutoyo Yamada, Hiroaki Kikuta, M. Furukawa, Satoshi Gunjishima, Yasunori Hara

{"title":"Effects of tip clearance flow on rotating stall inception process in an axial compressor rotor","authors":"Kazutoyo Yamada, Hiroaki Kikuta, M. Furukawa, Satoshi Gunjishima, Yasunori Hara","doi":"10.1299/KIKAIB.79.900","DOIUrl":"https://doi.org/10.1299/KIKAIB.79.900","url":null,"abstract":"Flow fields near rotating stall inception in a low-speed axial compressor rotor with two different tip clearances have been investigated by instantaneous measurements of casing wall pressure distributions using 30 high response pressure transducers and by detached eddy simulations (DES) using 120 million grid points. It is found that the stall inception process in the large tip clearance case is dominated by the breakdown of the rotor tip leakage vortex, in contrast to the spike-type stall inception in the small tip clearance case which is dominated by the leading-edge separation near the rotor tip. The vortex breakdown induces the large oscillation of the tip leakage vortex with its unsteady nature, resulting in the low-pressure regions in the instantaneous casing wall pressure field and the high pressure fluctuation region on the pressure side of the adjacent blade tip in the ensemble-averaged casing wall pressure field. The large blockage effect due to the tip leakage vortex breakdown causes the rotating disturbance propagating in the circumferential direction, which can appear and disappear with a slight change in the flow rate.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129085276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Enhancement of oxygen diffusivity in gas diffusion layer of PEFC with wettability distribution and effect of PTFE content 润湿性分布及PTFE含量对PEFC气体扩散层氧扩散率的增强作用

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2013-07-15 DOI: 10.1299/KIKAIB.79.1038

Ryo Koresawa, T. Daitoku, Y. Utaka

{"title":"Enhancement of oxygen diffusivity in gas diffusion layer of PEFC with wettability distribution and effect of PTFE content","authors":"Ryo Koresawa, T. Daitoku, Y. Utaka","doi":"10.1299/KIKAIB.79.1038","DOIUrl":"https://doi.org/10.1299/KIKAIB.79.1038","url":null,"abstract":"The mass transfer characteristics of the gas diffusion layer (GDL) are closely related to cell performance in polymer electrolyte fuel cell (PEFC). Thus, it is necessary to clarify the characteristics of liquid water distribution, microscopic conformation and the oxygen diffusivity in the GDL. In the present study, a hybrid type GDL is prepared using carbon paper GDL with a non-uniform wettability distribution to control the liquid water movement in the GDL and achieve both oxygen diffusion and moisture retention. To improve the oxygen diffusion characteristic of the previous reported hybrid GDL, hybrid type GDLs with different hydrophobic regions and different PTFE contents were fabricated. The effects of the different hydrophobic regions and PTFE content on the oxygen diffusivity and liquid water distribution were simultaneously measured using a galvanic cell type oxygen absorber and X-ray radiography using the BL20B2 beamline at SPring-8. In the result, the formation of oxygen diffusion paths was visualized; the pores in the hybrid GDL were formed from the hydrophobic regions, and the pores spread to the untreated region that was not hydrophobized (hydrophilic region) after the formation of the initial pores. Thus, the formation of oxygen diffusion paths enhanced the oxygen diffusivity. Additionally, the examination of effects of the hydrophobic region and PTFE content in the GDLs indicated the optimal amount of PTFE for a hybrid GDL.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121545202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

「第17回動力・エネルギー技術シンポジウム」特集号発刊にあたって在“第17届动力与能源技术研讨会”专刊出版之际

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2013-05-06 DOI: 10.1299/KIKAIB.79.228

保之高田

引用次数: 0

Deformation Behavior of Multi-Layered Ceramic Capacitors Block under Non-Frame Press 多层陶瓷电容器块在非框架压下的变形行为

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2013-05-06 DOI: 10.1299/KIKAIA.79.442

F. Naruse, N. Tada

{"title":"Deformation Behavior of Multi-Layered Ceramic Capacitors Block under Non-Frame Press","authors":"F. Naruse, N. Tada","doi":"10.1299/KIKAIA.79.442","DOIUrl":"https://doi.org/10.1299/KIKAIA.79.442","url":null,"abstract":"To investigate the deformation behavior of multi-layered ceramic capacitors (MLCCs) during production press process is very important to reduce over all MLCC size and increase the capacity of the MLCC through the enlargement of the electrode area. In the previous paper, the deformation of MLCC blocks in the uniaxial compression test was observed and the filling mechanism was clarified based on the measurement results. In this study, the non-frame press tests of MLCC blocks were carried out to realize the high precision press, in which the lateral compressive stress was given in addition to the longitudinal one. The deformation process was clarified based on the results of cross-sectional observation. In the edge part of the MLCC block, the interlayer space in Side-Gaps L and W was decreased by longitudinal strain and the lateral strain, whereas, at the central part of the MLCC block, the interlayer space in Side-Gaps L and W was decreased only by longitudinal strain. Since the difference in the deformation behavior between the central part and the edge part generated variations in the thickness of MLCC block, the width of the internal electrode part and the width of the Side-Gap, it was concluded that non-frame press was not suitable for high precision press of MLCC block.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116978165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of near-infrared laser-induced capillary wave method to measure viscosity and surface tension 近红外激光诱导毛细波法测量粘度和表面张力的研究

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2013-05-06 DOI: 10.1299/KIKAIB.79.690

H. Takiguchi, Y. Nagasaka

{"title":"Development of near-infrared laser-induced capillary wave method to measure viscosity and surface tension","authors":"H. Takiguchi, Y. Nagasaka","doi":"10.1299/KIKAIB.79.690","DOIUrl":"https://doi.org/10.1299/KIKAIB.79.690","url":null,"abstract":"We have developed a non-contact high speed viscosity sensing technique, laser-induced capillary wave (LiCW) method using pulsed volume heating laser of near-infrared wave length. The main idea of the present work is based on the capillary wave induced by volume heating, which behaves more physically simplified than the one induced by surface heating in decay process and has nanometer-scale amplitude even as relatively-small temperature rise. We have derived the new theory for the wave amplitude z (x, z) captured the physics of volume heating by giving the boundary condition of heat conduction into the depth direction. First, we compared the theoretical damping behavior of capillary wave for toluene by volume heating and surface heating. According to the proposed theory, the capillary wave induced by volume heating is formed by only the effect of the thermal expansion with having the negligible effect on the temperature dependence of surface tension. In addition, maximum temperature rise and wave amplitude of water and toluene, absorption length of them are extremely different from each other, was compared between volume heating with surface heating. As a result, it was confirmed that nanometer-scale capillary wave can be induced with the temperature rise of less than mK order by volume heating, which indicates that near-infrared wave length is more applicable to the thremophysical measurement technique as a heating light source. Finally, to demonstrate the validity of the new theory, we have measured viscosities and surface tensions of Newtonian liquids, which showed good agreement within ± 5 % from the reference values.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123660486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Numerical Simulation on Friction Drag Reduction Effect due to Straight-Chain Spring-Damper Elements in Turbulent Channel Flow 紊流通道中直链弹簧-阻尼器摩擦减阻效应的数值模拟

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2013-01-01 DOI: 10.1299/KIKAIB.79.1937

Yuta Utada, H. Mamori, K. Iwamoto, A. Murata, Y. Kawaguchi, H. Ando, T. Senda

引用次数: 2

Comparison of evaluation indices for acute subdural hematoma occurrence under occipital impact and effectiveness of head protector in judo 柔道枕部冲击下急性硬膜下血肿评价指标与护头效果的比较

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2012-12-01 DOI: 10.1299/KIKAIA.78.1631

Kazuki Affla, M. Omiya, M. Iteya, T. Kamitani, T. Tomatsu

{"title":"Comparison of evaluation indices for acute subdural hematoma occurrence under occipital impact and effectiveness of head protector in judo","authors":"Kazuki Affla, M. Omiya, M. Iteya, T. Kamitani, T. Tomatsu","doi":"10.1299/KIKAIA.78.1631","DOIUrl":"https://doi.org/10.1299/KIKAIA.78.1631","url":null,"abstract":"Beginning in 2012, judo has been selected to be a compulsory course in junior high schools in Japan. However, the number of participants, in particular beginners, who die or are injured in judo is higher than that for other sports. For this reason, there is a fear that there will be a drastic increase in the number of judo-related accidents leading to death or injury in junior high schools. The most serious form of head injury is acute subdural hematoma (ASDH). The purpose of the present study is to compare ASDH occurrence indices and to evaluate the effectiveness of using head protectors. Based on measurements of head acceleration during falling, the Head Injury Criterion (HIC), maximum angular acceleration and angular velocity variation range were calculated. The results indicated that the relative displacement between the brain and skull was most strongly correlated with the angular velocity variation range, which is thus a candidate evaluation index for ASDH. The results also suggest that in order to prevent ASDH, a head protector should be made of shock absorbing materials with a small coefficient of restitution, so as to reduce the rebound velocity of the skull after occipital impact.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126286716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Enhancement mechanism of impinging atomization by gas injection 注气增强冲击雾化机理

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2012-12-01 DOI: 10.1299/KIKAIB.78.1990

C. Inoue, Toshinori Watanabe, T. Himeno, S. Uzawa

{"title":"Enhancement mechanism of impinging atomization by gas injection","authors":"C. Inoue, Toshinori Watanabe, T. Himeno, S. Uzawa","doi":"10.1299/KIKAIB.78.1990","DOIUrl":"https://doi.org/10.1299/KIKAIB.78.1990","url":null,"abstract":"Impinging atomization, which has been widely utilized in liquid rocket propulsion systems, is able to produce fine drops at a rated operation. In contrast, however, the atomization characteristics deteriorate under off design conditions when injection velocity comes to be slower. In the present study, for improving atomization characteristics at off design operation, an effective technique is verified utilizing small amount of gas injection. The gas jet is supplied from a pressurized reservoir independent of the liquid supply system, and it is injected from the center of the liquid nozzles toward the impingement point. To clarify the flow field and the mechanism of the effectivity, experimental visualizations, drop size measurements and corresponding numerical analyses are carried out. It is elucidated that atomization is drastically promoted when the dynamic pressure of gas overcomes that of liquid at the impingement point. By the gas injection with the amount of only 1% of liquid mass flow rate, Sauter Mean Diameter (SMD) becomes one-tenth of the original SMD. In addition, the optimized atomization efficiency is achieved when the gas dynamic pressure is twice as much as the liquid at the impingement point.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132104210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Hydrophilic and hydrophobic double MPL coated gas diffusion layer to prevent drying-up and flooding of polymer electrolyte fuel cells 亲水和疏水双 MPL 涂层气体扩散层可防止聚合物电解质燃料电池干涸和淹没

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2012-11-19 DOI: 10.1299/KIKAIB.78.1849

T. Kitahara, H. Nakajima, M. Inamoto

{"title":"Hydrophilic and hydrophobic double MPL coated gas diffusion layer to prevent drying-up and flooding of polymer electrolyte fuel cells","authors":"T. Kitahara, H. Nakajima, M. Inamoto","doi":"10.1299/KIKAIB.78.1849","DOIUrl":"https://doi.org/10.1299/KIKAIB.78.1849","url":null,"abstract":"Gas diffusion layers (GDLs) coated with a hydrophobic microporous layer (MPL) have been commonly used to improve water management properties of polymer electrolyte fuel cells (PEFCs). In the present study, a novel hydrophilic and hydrophobic double MPL coated GDL was developed to achieve further enhancement of the PEFC performance under both low and high humidity conditions. Under low humidity conditions, a thin hydrophilic layer using titanium dioxide coated on the hydrophobic MPL is effective to conserve the humidity of the membrane electrode assembly (MEA), while a hydrophobic intermediate MPL between the hydrophilic layer and the carbon paper substrate prevents removal of water in the hydrophilic layer. This results in a significant enhancement of the ability of the MPL to prevent drying-up of the MEA. Under high humidity conditions, the double MPL coated GDL with appropriate pore diameter, thickness, and hydrophilic and hydrophobic properties is also effective to reduce flooding on the cathode catalyst layer, resulting in the higher PEFC performance compared with that for a hydrophobic MPL coated GDL.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127668953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2