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Effects of Freestream Turbulence on Bypass Transition of Separated Boundary Layer on Low-Pressure Turbine Airfoils

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Journal of Thermal Science 2012年第3期21卷 230-235页

作者： Hideo Taniguchi Hiroshi Sakai ken-ichi Funazaki Department of Mechanical Systems Engineering Faculty of EngineeringIwate University

This paper presents experimental studies on bypass transition of separated boundary layer on low-pressure turbine airfoils,focusing on the effects of freestream turbulence on the transition ***-wire probe measurements are performed on the suction side of an airfoil in the low-pressure linear turbine cascade at several Reynolds number *** turbulence is enhanced by use of turbulence grid located upstream of the *** results of this experimental study show that the location of boundary layer separation does not strongly de-pend on the freestream turbulence ***,as the freestream turbulence level increases,the size of separa-tion bubble becomes small and the location of turbulent transition moves *** size of separation bubble becomes small as the Reynolds number *** low freestream turbulence intensity,the velocity fluctuation due to Kelvin-Helmholtz instability is observed clearly in the shear layer of the separation *** high frees-tream turbulence intensity,the streak structures appear upstream of the separation location,indicating bypass transition of attached boundary layer occurs at high Reynolds number.

关键词： Aeroengine Low-Pressure Turbine Bypass Transition Separation Bubble

Influence of Heat Treatment on Hydroformability of TRIP Seamless Steel Tube

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Journal of Iron and Steel Research International 2014年第7期21卷 695-701页

作者： Zi-cheng ZHANG ken-ichi MANABE School of Mechanical Engineering and Automation Northeastern University Department of Mechanical Engineering Tokyo Metropolitan University

A low-carbon TRIP seamless steel tube, which is expected to be used in the hydroforming process, was successfully fabricated using piercing, cold-drawing and two-stage heat treatment process. The two-stage heat treatment is one crucial step because it significantly affects the microstructure and mechanical properties of TRIP seam less steel tube. In order to obtain the TRIP seamless steel tube with high hydroformability, several different heat treatment processes were conducted. The effects of heat treatment conditions （intercritical annealing （IA） and isothermal bainite treatment （IBT）） on the TRIP seamless steel tube hydroformability which was determined by free hydraulic bulge test were analyzed. Two different internal pressure boosting velocities of 0.2 and 0.5 MPa/s of free hydraulic bulge tests were adopted to determine the effective stress vs. effective strain curve of TRIP seamless steel tube. The results showed that for the predetermined IA condition, the maximum bulge height increased, but the maximum burst internal pressure decreased, with the increase of IBT holding time from 4 to 6 rain. For the predetermined IBT condition, the maximum bulge height decreased, but the maximum burst internal pressure increased, with the increase of IA holding time from 5 to 10 rain. By analyzing the free hydraulic bulge test results, it was found that the maximum bulge heights of TRIP seamless steel tubes with the internal pressure boosting velocity of 0.5 MPa/s were higher than those when the internal pressure boosting velocity was 0.2 MPa/s. This means that an appropriate deformation rate should be chosen to obtain the optimal hydroformability of TRIP seamless steel tube. In addition, the effective stress vs. effective strain curves of TRIP seamless steel tubes were ohtained with free hydraulic bulge test.

关键词： TRIP steel heat treatment hydroformability seamless tube hydraulic bulge test

Numerical and Experimental Studies of an Arc-heated Nonequilibrium Nozzle Flow

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Journal of Thermal Science 2003年第4期12卷 289-293页

作者： Michio Nishida ken-ichi Abe Hisashi Kihara Department of Aeronautics and Astronautics Kyushu University Fukuoka 812-8581 JapanDepartment of Aeronautics and Astronautics Kyushu University Fukuoka 812-8581 JapanDepartment of Aeronautics and Astronautics Kyushu University Fukuoka 812-8581 Japan

The arc-heated high-temperature gas is rotationally and vibrationally excited, and partially dissociated and ionized. When such gas flows inside a nozzle, energy transfers from rotational and vibrational energy modes to translational energy mode, and, in addition, recombination reactions occur. These processes are in thermal and chemical nonequilibrium. The present computations treat arc-heated nonequilibrium nozzle flows using a six temperature model (translational, rotational, N2 vibrational, O2 vibrational, NO vibrational and electron temperatures), and nonequilibrium chemical reactions of air. From the calculated flow properties, emission spectra at the nozzle exit were re-constructed by using the code for computing spectra of high temperature air. On the other hand, measurements of N2+(1-) emission spectra were conducted at the nozzle exit in the 20 kW arc-heated wind tunnel. Vibrational and rotational temperatures of N2 were determined using a curve fitting method on N2+(1-) emission spectra, with the vibrational and rotational temperatures for N2 and N2+ being assumed equal. Comparison of the measured and computed results elucidated that the experimental temperatures were larger than the computed ones. At present, we are trying to reveal the main reason for the discrepancy between the computed and measured N2 vibrational and rotational temperatures.

关键词： nozzle flow high temperature gas nonequilibrium flow arc-heated gas.

Synthesis and luminescent properties of low oxygen contained Eu^(2+)-doped Ca-α-SiAlON phosphor from calcium cyanamide reduction

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Journal of Rare Earths 2008年第2期26卷 198-202页

作者： PIAO Xianqing ken-ichi Machida Takashi Horikawa Hiromasa Hanzawa Center for Advanced Science and Innovation Osaka University 2-1 Yamadaoka Suita

A new convenient calcium cyanamide （CaCN2） reduction route was developed to synthesize the Eu^2＋ activated Ca-α-SiAION phosphors containing low oxygen content. The luminescence properties of the obtained products were investigated for white LEDs application. The critical Eu^2＋ concentration in various hosts and its effect on the photoluminescence properties were studied. The optimized sample （10at.% Eu^2＋ vs. Ca^2＋） could be efficiently excited by the current GaN/InGaN blue LED chips and provided emission intensity competitive with that of YAG：Ce^3＋（P46-Y3） standard, revealing that this phosphor was a potential candidate for phosphor-converted white LEDs.

关键词： nitride phosphor white LEDs SiAION Eu^2+ CaCN2 rare earths

Recycle for Sludge Scrap of Nd-Fe-B Sintered Magnet as Isotropic Bonded Magnet

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Journal of Rare Earths 2004年第1期22卷 168-171页

作者： Masahiro Itoh Masahiro Masuda Shunji Suzuki ken-ichi Machida Collaborative Research Center for Advanced Science and Technology Collaborative Research Center for Advanced Science and TechnologyCollaborative Research Center for Advanced Science and TechnologyCollaborative Research Center for Advanced Science and Technology Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Osaka University 2-1 Yamadaoka Suita Osaka 565-0871

The reduction diffusion method was performed for the sludge scrap of Nd-Fe-B sintered magnets with adding Ca metal to recover the oxidized Nd-Fe-B phase. After washing the resultant powders to remove Ca metal component, the powders obtained were recycled as an isotropic magnetic powder by the melt spinning method. The magnetic properties of powders as recycled were inferior, especially for the coercivity value, due to the deletion of rare earth metals during the washing process. The adjustment of metal composition, i.e., the addition of Nd metal, at the melt spinning process improved the magnetic properties to be B r=～0.75 T, H cj=～0.93 mA·m -1, and (BH) max=～91 kJ·m -3. The magnetic properties of the bonded magnets prepared from the composition-adjusted powders were B r=～0.66 T, H cj=～0.92 mA·m -1, and (BH) max=～70 kJ·m -3, which are approximately comparable to the commercially available MQPB boned one (B r=～0.73 T, H cj=～0.79 mA·m -1, and (BH) max=～86 kJ·m -3).

关键词： Nd-Fe-B sintered magnet recycling isotropic Nd-Fe-B bonded magnet melt-spinning method sludge scrap rare earths

Integrable discretizations of the Dym equation

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Frontiers of Mathematics in China 2013年第5期8卷 1017-1029页

作者： Bao-Feng FENG Jun-ichi INOGUCHI kenji KAJIWARA ken-ichi MARUNO Yasuhiro OHTA Department of Mathematics The University of Texas-Pan American Edinburg TX 78539 USA Department of Mathematical Sciences Yamagata University 1-4-12 Kojirakawa-machi Yamagata 990-8560 Japan Institute of Mathematics for Industry Kyushu University 744 Motooka Fukuoka 819-8581 Japan Department of Mathematics Kobe University Rokko Kobe 657-8501 Japan

Integrable discretizations of are proposed. N-soliton solutions for analogues of the complex and real Dym the complex and real Dym equations both semi-discrete and fully discrete equations are also presented.

关键词： Dym equation integrable discretization N-soliton solution

A tree-shaped motion strategy for robustly executing robotic assembly tasks

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第12期11卷 986-991页

作者： Yusuke BOTA Hajime MIZUYAMA Akio NODA Tatsuya NAGATANI ken-ichi TANAKA Department of Mechanical Engineering and Science Kyoto University Yoshida-Honmachi Advanced Technology R&D Center Mitsubishi Electric Corporation 8-1-1Tsukaguchi-Honmachi

An assembly robot needs to be capable of executing an assembly task robustly under various *** attain this goal,we use a task sequence tree model originally proposed for manual *** model regards an assembly task under uncertainties as a transformation of the contact state *** concept may contain several contact states with probabilities but these are transformed through a series of task elements into the contact state concept having only the goal state at the *** transformed contact state concept can be classified according to the terminal condition of each task ***,the whole assembly task can be designed as a tree-shaped contingent strategy called a task sequence *** paper proposes a systematic approach for reconfiguring a task sequence tree model for application to a robotic assembly *** addition,by taking a 2D peg-in-hole insertion task to be performed by a robot equipped with a force sensor as an example,we confirm that the proposed approach can provide a robust motion strategy for the task and that the robot can actually execute the task robustly under bounded uncertainty according to the strategy.

关键词： Active compliant motion Contact states Motion strategy Robotic assembly Task sequence tree

Aero-Thermal Performances of Leakage Flows Injection from the Endwall Slot in Linear Cascade of High-Pressure Turbine

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Journal of Thermal Science 2015年第1期24卷 49-57页

作者： Wan Aizon W Ghopa Zambri Harun ken-ichi Funazaki Takemitsu Miura Department of Mechanical and Materials Engineering Universiti Kebangsaan Malaysia Department of Mechanical Engineering Iwate University

The existence of a gap between combustor and turbine endwall in the real gas turbine induces to the leakages phenomenon. However, the leakages could be used as a coolant to protect the endwaU surfaces from the hot gas since it could not be completely prevented. Thus, present study investigated the potential of leakage flows as a function of film cooling. In present study, the flow field at the downstream of high-pressure turbine blade has been investigated by 5-holes pitot tube. This is to reveal the aerodynamic performances under the influenced of leakage flows while the temperature measurement was conducted by thermoehromic liquid crystal （TLC）. Expe- rimental has significantly captured theaerodynamics effect of leakage flows near the blade downstream. Further- more, TLC measurement illustrated that the film cooling effectiveness contours were strongly influenced by the secondary flows behavior on the endwall region. Aero-thermal results were validated by the numerical simulation adopted by commercial sottware, ANSYS CFX 13. Both experimental and numerical simulation indicated almost similar trendinaero and also thermal behavior as the amount of leakage flows increases.

关键词： endwall fllmcooling leakage flows secondary flows aerodynamic loss film cooling effectiveness

Simultaneous X-Ray Emission Processes Induced by High-Energy Ion-Atom Collisions:Radiative Electron Capture

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原子与分子物理学报 1990年第4期7卷 1590-1594页

作者： Tsutomu Watanabe ken-ichi Hino Department of Physics Division of Natural SciencesInternational Christian UniversityMitaka-shiTokyo 181 JapanDepartment of Chemistry and PhysicsUniversity of Electro CommunicationsChofu-shiTokyo 182 Japan

We discussed the theoretical consistency in the treatment of Xray emission processes due to the deceleration of an electron on the occasion of transfer from atom to projectile *** cross sections do depend on the coordinate frame *** unphysical feature is from the approximate formulas of three particle scattering *** discussed a guide principle and reported some recent calculations.

关键词： X射线发射离子-原子碰撞辐射电子俘获