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1.
Seung-chai Jung Byung-Hoon Park Hyun Ko Woong-sup Yoon 《Journal of Mechanical Science and Technology》2009,23(3):823-835
Effects of the bulk inlet velocity on the characteristics of dual-inlet side-dump flows are numerically investigated. Non-reacting
subsonic turbulent flow is solved by a preconditioned Reynolds-averaged Navier-Stokes equation system with low-Reynolds number
k − ɛ turbulence model. The numerical method is properly validated with measured velocity distributions in the head dome and the
combustor. With substantial increase in the bulk inlet velocity, general profiles of essential primary and secondary flows
normalized by the bulk inlet velocity are quantitatively invariant to the changes in the bulk inlet velocity.
This paper was recommended for publication in revised form by Associate Editor Do Hyung Lee
Seung-chai Jung received his B.S. degree in Mechanical Engineering from Yonsei University, Korea, in 2001. He then received his M.S. degree
in Mechanical Engineering from Yonsei University, Korea, in 2005. Mr. Jung is currently a Ph. D. candidate at Yonsei University,
where he is majoring in Mechanical Engineering. Mr. Jung’s research interests include propulsion system and particle-surface
collision dynamics.
Byung-Hoon Park received his B.S. degree in Mechanical Design and Production Engineering from Yonsei University in 2003. He is currently
a Ph.D. candidate in Yonsei University in Seoul, Korea. His research interests include performance design of propulsion systems
and nu-merical analysis of instability in multiphase turbulent reacting flow-fields.
Hyun Ko received his B.S. degree in Aerospace Engineering from Chonbuk National University, Korea, in 1996. He then received his
M.S. degree in Mechanical Design from Chonbuk National University, Korea, in 1998. In 2005, he obtained his Ph.D. degree from
Yonsei University, where he majored in mechanical engineering. Dr. Ko is currently a Principal Research Engineer of the MicroFriend
Co., Ltd. in Seoul, Korea. His research interests include propulsion related systems and computational fluid dynamics.
Woong-sup Yoon received his B.S. degree in Mechanical Engineering from Yonsei University, Korea, in 1985. He then received his M.S. degree
from University of Missouri-Rolla in 1989. In 1992, he obtained his Ph.D. degree from the University of Alabama in Huntsville,
where he majored in mechanical and aerospace engineering. Dr. Yoon is currently a professor at the School of Mechanical Engineering
at Yonsei University in Seoul, Korea. His research interests include propulsion system and particle-related environmental/
thermal engineering. 相似文献
2.
Breakup and spray formation by impinging liquid jets introduced into a low-speed cross-flow are experimentally investigated.
Effects of the cross-flows on the macroscopic and microscopic spray parameters are optically measured in terms of jet Weber
number and liquid-to-gas momentum ratio. The liquid stream undergoes Rayleigh jet breakup at lower jet Weber numbers and bag/plume
breakup at higher momentum ratio through Kelvin-Helmholtz instability. In particular, the first and the second wind breakup
occur at an intermediate jet Weber number. At higher jet Weber numbers, the hydrodynamic impact waves commands and the effect
of the convective gas flows is insignificant. The breakup length rises in proportion to the jet Weber number, but starts to
decrease when the jet Weber number further rises over 1000. The cross-flow promotes the jet breakup and renders a finer spray
in an entire range of injection velocities.
This paper was recommended for publication in revised form by Associate Editor Gihun Son
Woong-Sup Yoon is a Professor in the School of Mechanical Engineering at Yonsei University. His current research interests are in wave instabilities,
unusual spray formation, emission control, and propulsion system modeling. He received a BS degree from the Department of
Mechanical Engineering, Yonsei University, in 1985; an MS degree from the Department of Mechanical Engineering, University
of Missouri-Rolla, in 1989; and a Ph.D degree from the Department of Mechanical and Aerospace Engineering, the Unversity of
Alabama in Huntsville, in 1992.
Sang-seung Lee received his B.S. degree in Weapons Engineering from Korea Military Academy, Korea, in 2002. He then received his M.S. degrees
from Yonsei University, in 2006. Mr. Lee is currently a Lecturer at the School of Weapons Engineering at Korea Military Academy
in Seoul, Korea. He serves as an Editor of the Journal of Mechanical Science and Technology. Mr. Lee’s research interests
include Ramjet, Atomization of injector.
Won-ho Kim received his B.S. degree in Mechanical Engineering from Yonsei University, Korea, in 2003. Mr. Kim has then gone on to do
graduate work at the Ph.D in the School of Mechanical Engineering at Yonsei University in Seoul, Korea. Mr. Kim’s research
interests include Atomization of 2phase flow and Dust collection efficiency. 相似文献
3.
Jeonghoon Yoo Myung Wook Hyun Jun Ho Choi Sungchul Kang Seung-Jong Kim 《Journal of Mechanical Science and Technology》2009,23(8):2236-2243
The response surface method combined with the design of experiment-based design optimization of a variable stiffness joint
(VSJ) is presented in this article. A VSJ used in a manipulator of a robot arm to support 1 kg payload at the end is designed
by considering the minimization of the total weight as the objective function. Owing to the requirement of large rotational
stiffness of the VSJ, over 10 N · m, ring-type permanent magnets are adopted. First, a model composed of two permanent magnets was initially manufactured and
tested for comparison with the analysis results. Then, a three-ring-type permanent magnet-based model is suggested and optimized
to increase the torque of VSJ. The finite element method is used as a magnetic field analysis method to substitute for the
expensive experimental process. Optimization results decrease the weight from 0.899 kg to 0.538 kg, still satisfying the requirement
for the rotational stiffness.
This paper was recommended for publication in revised form by Associate Editor Tae Hee Lee
Jeonghoon Yoo received his B.S. and M.S. degrees in Mechanical Design and Production Engineering from Seoul National University, in 1989
and 1991, respectively. He then received his Ph.D. degrees from the University of Michigan, Ann Arbor, in 1999. Dr. Yoo is
currently a Professor at the School of Mechanical Engineering at Yonsei University in Seoul, Korea. Dr. Yoo’s research interests
include analysis and design of electromagnetic field systems.
Myung Wook Hyun received his B.S. and M.S. degrees in Mechanical Engineering from Yonsei University, Korea, in 1995 and 1997, respectively.
While studying for his M.S. degree, Mr. Hyun also studied variable stiffness unit design. He is now working at Samsung Electronics,
Co. Ltd..
Jun Ho Choi received his B.S. and M.S. degrees in Mechanical Design from Hanyang University, Korea and his Ph.D. degree from the University
of Michigan, Ann Arbor. He is currently a senior research scientist in the Korea Institute of Science and Technology. His
research interests include nonlinear control, manipulator control, and safe-joint design.
Sungchul Kang received his B.S., M.S., and Ph.D. degrees in Mechanical Design and Production Engineering from Seoul National University,
Korea, in 1989, 1991, and 1998 respectively. Dr. Kang is currently a Principal Research Scientist in the Center for Cognitive
Robotics Research, Korea Institute of Science and Technology, in Seoul, Korea. Dr. Kang’s research interests include mobility
and manipulation of field and service robots and haptics.
Seung-Jong Kim received his B.S. degree in Mechanical Engineering from Seoul University, Korea, in 1989, and his M.S. and Ph.D. degrees
from KAIST in 1991 and 1998, respectively. Dr. Kim is currently a Principal Research Scientist at the Korea Institute of Science
and Technology in Seoul, Korea. Dr. Kim’s research interests include the design, control, and dynamic analysis of mechatronic
systems. 相似文献
4.
Dong Ho Kim Jong Hyun Choi Chang Woo Son Yoon Su Baek 《Journal of Mechanical Science and Technology》2009,23(2):335-343
This paper deals with analysis and experiments of an axial flux PM (AFPM) brushless dc motor with minimized cogging torque.
Recently, many optimal designs for the AFPM motor have been done by finite element (FE) analysis, but such analysis is time-consuming.
In this study, the equation of magnetic flux lines existing between PMs and core is assumed mathematically and the minimum
cogging torque is calculated theoretically and geometrically without FE analysis. The form of equation is assumed to be a
2nd order polynomial. The skew angle that makes the cogging torque minimized is calculated theoretically, and the value of minimum
cogging torque is compared with the results obtained by FE analysis and experiments. The maximum cogging torque of a proposed
AFPM motor has the smallest value approximately at a skew angle of 4° in both the theoretical and FE analysis. Compared with
the non-skewed motor, the cogging torque of the skewed motor can be decreased to over 90%, which has a value of 5% of the
rated torque. Two types of stator cores, with the skew angle of 0° and 4°, are analyzed, manufactured, and tested experimentally.
This paper was recommended for publication in revised form by Associate Editor Hong Hee Yoo
Dong Ho Kim received B.S. and M.S. degrees in Mechanical Engineering from Pusan National University in 1982 and 1984, respectively. He
then received his Ph.D. degree from Yonsei University in 2007. Dr. Kim is currently a Professor at the Department of Automation
and Robots at Kyonggi Institute of Technology in Gyeonggi, Korea. His research interests are in the area of production automation.
Jong Hyun Choi received B.S., M.S., and Ph.D. degrees in Mechanical Engineering from Yonsei University, Seoul, Korea, in 1996, 1998, and
2006, respectively. Dr. Choi is currently a post-doctor at the School of Mechanical Engineering at Yonsei University. His
research interests are in the area of electromagnetic actuators and magnetic levitation system.
Chang Woo Son received a B.S. from Kyungwon University, Seoul, Korea, in 2006, and his M.S. degree from Yonsei University in 2008, all
in mechanical engi-neering. He is currently a research engineer at DA Laboratory of LG Electronics in Seoul, Korea. His research
interests are in the area of electromagnetic actuators.
Yoon Su Baek received B.S. and M.S. degrees from Yonsei University, Seoul, Korea, in 1979 and 1981, respectively, and M.S. and Ph.D. degrees
from Oregon State University in 1986 and 1990, respectively, all in mechanical engineering. He worked for Samsung Heavy Industry
Ltd. as head research engineer at Mechatronics Research Center from 1990 to 1993. Dr. Baek is currently a Professor at the
School of Mechanical Engineering at Yonsei University. His research interests are motion devices and robotics, especially
relating to multi-D.O.F. actuators. He is also interested in magnetic brake and levitation system. 相似文献
5.
Kwang Hoon Park Kang Mo Yang Keon Woo Lee Hyung Hee Cho Hee Chul Ham Ki Young Hwang 《Journal of Mechanical Science and Technology》2009,23(7):1852-1857
A slot film cooling technique has been used to protect a combustor liner from hot combustion gas. This method has been developed
for gas turbine combustors. A ramjet combustor exposed to high temperature can be protected properly with a multi-slot film
cooling method. An experimental study has been conducted to investigate the change of the first slot angle under recirculation
flow and the influence of wiggle strip within a slot, which affects the film cooling effectiveness. The first slot angle has
been changed to understand the effect of the injection angle on the film cooling effectiveness in a recirculation zone. The
distribution of dimensionless temperature was obtained by a thermocouple rake to investigate the wiggle strip effect, and
the adiabatic film cooling effectiveness on downstream wall was measured by a thermochromic liquid crystal (TLC) method. At
the first slot position, the film cooling effectiveness decreases significantly because of the effects of recirculation flow.
The lip angle of the first slot affects slightly on the film cooling effectiveness. The wiggle strip reinforces the structure
of slot and keeps the uniform open area of slot. However, it induces three dimensional flows and enhances the flow mixing
between the main flow and the injected slot flow. Therefore, the wiggle strip decreases slightly the overall film cooling
effectiveness.
This paper was presented at the 7th JSME-KSME Thermal and Fluids Engineering Conference, Sapporo, Japan, October 2008.
Kwanghoon Park received his M.S degree in Mechanical Engineering from Yonsei University, Seoul, Korea in 2007. He is currently working for
an education of an officer as a drillmaster in Army Consolidated Logistics School.
Kang Mo Yang joined the Republic of Korea Army in 2004. He is currently working towards the M.S. degree at the Department of Mechanical
Engineering, Yonsei University.
Keon Woo Lee received his M.S. degree in Mechanical Engineering from Yonsei University, Seoul, Korea in 2008. In 2008, he joined the Doosan
heavy industries & Construction Co, LTD, where he is a member of the IGCC Business Team.
Hyung Hee Cho received his PhD degree in Mechanical Engineering from University of Minnesota, Minneapolis, MN in 1992. In 1995, he joined
the Department of Mechanical Engineering, Yonsei University, Seoul, Korea, where he is currently a full professor in the School
of Mechanical Engineering. His research interests include heat transfer in turbomachineries, rocket/ramjet cooling as well
as nanoscale heat transfer in thin films, and microfabricated thermal sensors.
Hee Cheol Ham received his PhD degree in Mechanical Engineering from Yonsei University, Seoul, Korea in 2001. In 1984, he joined the Agency
for Defense Development, Daejeon, Korea, where he is currently a Principal Researcher.
Ki Young Hwang received his Ph.D. degree in Mechanical Engineering from Yonsei University, Seoul, Korea in 1994. In 1979, he joined the
Agency for Defense Development, Daejon, Korea, where he is currently a principal researcher in the Airbreathing Propulsion
Directorate. 相似文献
6.
Dongji Xuan Zhenzhe Li Jinwan Kim Youngbae Kim 《Journal of Mechanical Science and Technology》2009,23(3):717-728
The output power efficiency of the fuel cell system mainly depends on the required current, stack temperature, air excess
ratio, hydrogen excess ratio, and inlet air humidity. Therefore, the operating conditions should be optimized to get maximum
output power efficiency. In this paper, a dynamic model for the fuel cell stack was developed, which is comprised of a mass
flow model, a gas diffusion layer model, a membrane hydration, and a stack voltage model. Experiments have been performed
to calibrate the dynamic Polymer Electrolyte Membrane Fuel Cell (PEMFC) stack model. To achieve the maximum output power and
the minimum use of hydrogen in a certain power condition, optimization was carried out using Response Surface Methodology
(RSM) based on the proposed PEMFC stack model. Using the developed method, optimal operating conditions can be effectively
selected in order to obtain minimum hydrogen consumption.
This paper was recommended for publication in revised form by Associate Editor Tong Seop Kim
Dong-Ji Xuan received his B.S. degree in Mechanical Engineering from Harbin Engineering University, China in 2000. He then received his
M.S. degree in Mechanical Engineering from Chonnam National University, South Korea in 2006. Currently, he is a Ph.D. candidate
of the Department of Mechanical Engineering, Chonnam National University, South Korea. His research interests include control
and optimization of PEM fuel cell system, dynamics and control, and mechatronics.
Zhen-Zhe Li received his B.S. degree in Mechanical Engineering from Yanbian University, China in 2002. He then received his M.S. degree
in Aerospace Engineering from Konkuk University, South Korea in 2005 and his Ph.D. degree in Mechanical Engineering from Chonnam
National University, South Korea in 2009. Dr. Li is currently a Researcher of the Department of Mechanical Engineering in
Chonnam National University, South Korea. Dr. Li’s research interests include applied heat transfer, fluid mechanics, and
optimal design of thermal and fluid systems.
Jin-Wan Kim received his B.S. degree in Aerospace Engineering from Chosun University, South Korea in 1990. He then received his M.S.
degree in Aerospace and Mechanical Engineering from Korea Aerospace University, South Korea in 2003 and his Ph.D degree in
Mechanical Engineering from Chonnam National University, South Korea in 2008. He is currently a Post Doctor of the Department
of Mechanical Engineering in Chonnam National University, South Korea. His research interests include control of hydraulic
systems, dynamics and control, and mechatronics.
Young-Bae Kim received his B.S. degree in Mechanical Design from Seoul National University, South Korea in 1980. He then received his M.S.
degree in Mechanical Engineering from the Korean Advanced Institute of Science and Technology (KAIST), South Korea in 1982
and his Ph.D. degree in Mechanical Engineering from Texas A&M University, USA in 1990. Dr. Kim is currently a Professor of
the School of Mechanical and Systems Engineering in Chonnam National University, South Korea. Dr. Kim’s research interests
include mechatronics, dynamics and control, and fuel cell hybrid electric vehicle (FCHEV) systems. 相似文献
7.
Sunwoo Park Hueseok Choi Kihong Ryu Sayup Kim Youngho Kim 《Journal of Mechanical Science and Technology》2009,23(1):204-211
In this study, biomechanical characteristics during the whole process of gait initiation for twenty normal healthy volunteers
were determined by the motion analysis with six near-infrared cameras, four forceplates, and an EMG system. Gait initiation,
a transitional movement phenomenon from quiet stance to steady-state walking, involves a series of muscular activities, GRFs,
movements of COP and COM, and joint motions. Results showed that the location of the net COP to be most lateral during double
limb stance at the beginning of gait initiation. During gait initiation, changes in anteroposterior components of GRFs were
first found and then changes in vertical components followed. Hip and knee motions were found before the ankle joint motion.
Walking speed, step length, and stride length gradually increased until the second step. The interaction between the COM and
COP is tightly regulated to control the trajectory of the COM and thereby control total body balance.
This paper was recommended for publication in revised form by Associate Editor Hong Hee Yoo
Sun-Woo Park received a B.S. degree in Biomedical Engineering from Yonsei University in 2006. He is currently a M.S. candidate in the
Department of Biomedical Engineering, Yonsei University, Korea. His research interests in the area of Human Movement and detection
of gait phase using motion sensors.
Hue-Seok Choi received a B.S. degree in Computer Engineering from Daejeon University in 2004. He is currently a P.D. candidate at the Department
of Biomedical Engineering at Yonsei University, Korea. His research interests are in the area of Human Movement and Rehabilitation
Engineering.
Ki-Hong Ryu received a B.S. and M.S. degrees in Biomedical Engineering from Yonsei University in 1998 and 2001, respectively. He is currently
a P.D. candidate in the Department of Biomedical Engineering, Yonsei University, Korea. His research interests are in the
area of Human Movement and Gait Training System using Functional Electrical Stimulation.
Sa-Yup Kim received a B.S. degree in Electrical Engineering from Yeungnam University in 2002 and M.S. degrees in Biomedical Engineering
from Yonsei University in 2006. He is currently working from Korea Institute of Industrial Technology in Cheonan, Korea.
Young-Ho Kim received a B.S. degree in Mechanical Engineering from Hanyang University in 1982. He then went on to receive his M.S. and
Ph.D. degrees from University of Iowa in 1989 and 1991, respectively. He is currently a Professor in the Department of Biomedical
Engineering, Yonsei University, Korea. His research interests are in the area of Human Movement, Rehabilitation Engineering,
and Biomechanics. 相似文献
8.
The location and the size of a geometrically defected region in the side wall of a corner, which is generated during the flat
end-milling process, are investigated through experiments and geometrical analysis. A corner with inner and outer surfaces
is assumed to be made up of one arc-surface patch and two flat-surface patches. Based on the previous findings that the change
of material removal per tooth affects the geometry of the end-milled side wall, it is expected that the geometrically defected
regions are located around the corner when the tool is approaching and leaving the arc surface. In this respect, analytic
models are proposed to predict the location and the size of a geometrically defected region, which are then validated via
comparison with the experimental results.
This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim
Kun Sang Lee received his B. S. degree in Mechanical Engineering from Seoul National University, Korea, in 1982. He then received his
Dipl.-Ing. and Dr.-Ing. degrees from Technical University of Berlin, Germany, in 1991 and 1993, respectively. Dr. Lee is currently
a Professor at the School of Mechanical and Automotive Engineering at Kookmin University in Seoul, Korea. He serves as a Staff
of the Korea Engineering Education Research Center. His research interests include precision machining, high energy beam material
processing, and creative design methodology.
Kang Kim received his B. S. and M. S. degrees in Mechanical Design and Production Engineering from Seoul National University, Korea,
in 1982 and 1984, respectively. He then received his Ph.D. degree from Purdue University, USA, in 1992. Dr. Kim is currently
a Professor at the School of Mechanical and Automotive Engineering at Kookmin University in Seoul, Korea. His research interests
include material removal processes, and concurrent engineering. 相似文献
9.
Jong Won Choi Mo Se Kim Jeong-Seob Shin Sai-Kee Oh Baik-Young Chung Min Soo Kim 《Journal of Mechanical Science and Technology》2009,23(7):1858-1865
In HVAC system, the oil circulation is inevitable because the compressor requires the oil for lubrication and sealing. A small
portion of the oil circulates with the refrigerant flow through the system components while most of the oil stays or goes
back to the compressor. Because oil retention in refrigeration systems can affect system performance and compressor reliability,
proper oil management is necessary in order to improve the compressor reliability and increase the overall efficiency of the
system. This paper describes a numerical analysis of oil distribution in each component of the commercial air conditioning
system including the suction line, discharge line and heat exchanger. In this study, system modeling was conducted for a compressor,
discharge line, condenser, expansion valve, evaporator and suction line. Oil separation characteristics of the compressor
were taken from the information provided by manufacturer. The working fluid in the system was a mixture of a R-410A refrigerant
and PVE oil. When the oil mass fraction (OMF) was assumed, oil mass distribution in each component was obtained under various
conditions. The total oil hold-up was also investigated, and the suction line contained the largest oil hold-up per unit length
of all components.
This paper was presented at the 7th JSME-KSME Thermal and Fluids Engineering Conference, Sapporo, Japan, October 2008.
Min Soo Kim received his B.S., M.S., and Ph.D. degree at Seoul National University, Korea in 1985, 1987, and 1991, respectively. After
Ph.D. degree, Prof. Kim worked at National Institute of Standards and Technology (NIST) in U.S.A. for about three years. He
is currently a professor at the School of Mechanical and Aerospace Engineering of Seoul National University, Korea.
Jong Won Choi received B.S. degree in Mechanical Engineering from Korea University in Seoul, Korea, in 2004, and then received M.S. degrees
from Seoul National University in 2006. He is currently a student in Ph.D. course at the School of Mechanical and Aerospace
Engineering of Seoul National University in Seoul, Korea. His research interests include refrigeration system, micro-fluidic
devices, and PEM fuel cell as an alternative energy for next generation.
Mo Se Kim received B.S. degree in Mechanical and Aerospace Engineering from Seoul National University in Seoul, Korea, in 2007. He
is currently a student in M.S. course at the School of Mechanical and Aerospace Engineering of Seoul National University in
Seoul, Korea. He had studied on the oil migration in the heat pump system, and now he studies on the refrigeration system
using an ejector.
Baik-Young Chung received his B.S., M.S., and Ph.D. degrees in Mechanical Engineering from Inha University, Korea in 1984, 1986, and 2001,
respectively. He is currently a research fellow of HAC Research Center at LG Electronics. He is responsible for the commercial
air conditioner group.
Sai-Kee Oh received B.S. degree in Mechanical Engineering from Seoul National University, Korea in 1989, and then received M.S. and
Ph.D. degrees from KAIST, Korea in 1991 and 1997, respectively. He is currently a principal research engineer of HAC Research
Center at LG Electronics. He is responsible for the residential air conditioner group.
Jeong-Seob Shin received B.S. degree in Machine Design and Production Engineering from Hanyang University, Korea in 1988, M.S. degree in
Mechanical Engineering from KAIST, Korea in 1991, and Ph.D. degree in Mechanical Engineering from POSTECH, Korea in 2004.
He has joined HAC Research Center at LG Electronics since 2006 as a principal research engineer. 相似文献
10.
Jae Hyuk Choi Junhong Kim SangKyu Choi Byoung-Ho Jeon Osamu Fujita Suk Ho Chung 《Journal of Mechanical Science and Technology》2009,23(3):707-716
A numerical study on soot deposition in ethylene diffusion flames has been conducted to elucidate the effect of thermophoresis
on soot particles under a microgravity environment. Time-dependent reactive-flow Navier-Stokes equations coupled with the
modeling of soot formation have been solved. The model was validated by comparing the simulation results with the previous
experimental data for a laminar diffusion flame of ethylene (C2H4) with enriched oxygen (35% O2 + 65% N2) along a solid wall. In particular, the effect of surrounding air velocity as a major calculation parameter has been investigated.
Especially, the soot deposition length defined as the transverse travel distance to the wall in the streamwise direction is
introduced as a parameter to evaluate the soot deposition tendency on the wall. The calculation result exhibits that there
existed an optimal air velocity for the early deposition of soot on the surface, which was in good agreement with the previous
experimental results. The reason has been attributed to the balance between the effects of the thermophoretic force and convective
motion.
This paper was recommended for publication in revised form by Associate Editor Ohchae Kwon
Jae Hyuk Choi received his B.S. and M.S. degrees in Marine System Engineering from Korea Maritime University in 1996 and 2000, respectively.
He then went on to receive a Ph.D. degrees from Hokkaido university in 2005. Dr. Choi is currently a BK21 Assistant Professor
at the School of Mechanical and Aerospace Engineering at Seoul National University in Seoul, Korea. Dr. Choi’s research interests
are in the area of reduction of pollutant emission (Soot and NOx), high temperature combustion, laser diagnostics, alternative
fuel and hydrogen production with high temperature electrolysis steam (HTES).
Junhong Kim received his B.S., M.S., and Ph. D degrees in Mechanical Engineering from Seoul National University in 1998, 2000, and 2004,
respectively. His research interests include lifted flames, edge flames, and numerical simulation.
Sang Kyu Choi received his B.S. degree in Mechanical Engineering from Seoul National University in 2004. He is a Ph. D student in the School
of Mechanical Engineering, Seoul National University. His research interests include edge flames, oxy-fuel combustion, and
numerical simulation.
Byoung ho Jeon received his B.S degrees in Mechanical Engineering from kangwon University in 1998, and M.S., Ph. D. degrees in Mechanical
Engineering from Hokkaido University in 2002, 2008, respectively. Dr Jeon is working at Korea Aerospace Research Institute
from 2007. June. as Gasturbine engine developer. Jeon’s research interests are in the area of reduction of pollutant emission
(Soot and Nox), High temperature combustion, combustion system (Furnace, Combine Generation system, IGCC, CTL), and Fire safety
in building.
Osamu Fujita received his B.S., M.S., and Ph. D. degrees in Mechanical Engineering from Hokkaido University in 1982, 1984, and 1987, respectively.
Prof. Fujita is currently a Professor at the division of Mechanical and space Engineering at Hokkaido University in sapporo,
Japan. Prof. Fujita’s research interests are in the area of reduction of pollutant emission (Soot and Nox), solid combustion,
catalytic combustion, high temperature combustion, alternative fuel and fire safety in space.
Suk Ho Chung received his B.S. degree in Mechanical Engineering in 1976 from Seoul National University, and his M.S. and Ph. D. degree
in Mechanical Engineering in 1980 and 1983, respectively from Northwestern University. He is a professor since 1984 in the
School of Mechanical and Aerospace Engineering, Seoul National University. His research interests cover combustion fundamentals,
pollutant formation, and laser diagnostics. 相似文献
11.
Dong Hyun Kim Kyung Su Oh Seungho Park 《Journal of Mechanical Science and Technology》2009,23(6):1536-1543
This paper reports the design of a novel twisting-type micromirror actuation system. The actuating mechanism for driving the
micromirror combines two paralleled bimorph actuators bending in opposite directions for rotational control of the micromirror.
Each actuator is structured by gold and silicon dioxide or nickel and silicon nitride thin films with embedded polysilicon
line heaters. With a size of only 15μm in width, 1.3μm in thickness, and 100μm in length, two bimorph actuators can result
in a vertical displacement of 25μm at 10 volts dc with the span of 120μm, and thus the micromirror can rotate by angles over
20°, which is a significant improvement, compared to conventional tilting-type micromirrors.
This paper was recommended for publication in revised form by Associate Editor Dongsik Kim
Dong Hyun Kim received his B.S. and M.S. degrees in Mechanical Engineering from Hongik University, Korea, in 2005 and 2007, respectively.
Mr. Kim is currently graduate student in the department of Mechanical Engineering at Hongik University in Seoul, Korea. His
research interests include micro and nanoscale heat transfer and silicon crystallization technologies for displays.
Kyung Su Oh received his B.S. and M.S. degrees in Mechanical Engineering from Hongik University, Korea, in 2005 and 2007, respectively.
Mr. Oh is currently a research scientist at LG Chem. Ltd. His research interests include nanoscale heat transfer, nanotubes
and fuel cells and molecular simulation technology.
Seungho Park received his B.S. and M.S. degrees in Mechanical Engineering from Seoul National University, Korea, in 1981 and 1983, respectively.
He then received his Ph.D. degree from U.C. Berkeley, U.S.A. in 1989. Dr. Park is currently a Professor at the department
of Mechanical and System Design Engineering at Hongik University in Seoul, Korea. He served as a director of general affairs
of KSME. Dr. Park’s research interests include micro and nanoscale heat transfer, molecular dynamics simulation and silicon
crystallization technologies for displays. 相似文献
12.
Friction-induced ignition modeling of energetic materials 总被引:1,自引:0,他引:1
Min-cheol Gwak Tae-yong Jung Jack Jai-ick Yoh 《Journal of Mechanical Science and Technology》2009,23(7):1779-1787
The heat released during the external frictional motion is a factor responsible for initiating energetic materials under all
types of mechanical stimuli including impact, drop, or penetration. We model the friction-induced ignition of cyclotrimethylenetrinitramine
(RDX), cyclotetramethylene-tetranitramine (HMX), and ammonium-perchlorate/ hydroxylterminated-polybutadiene (AP/HTPB) propellant
using the BAM friction apparatus and one-dimensional time to explosion (ODTX) apparatus whose results are used to validate
the friction ignition mechanism and the deflagration kinetics of energetic materials, respectively. A procedure to obtain
the time-to-ignition for each energetic sample due to friction is outlined.
This paper was presented at the 7th JSME-KSME Thermal and Fluids Engineering Conference, Sapporo, Japan, October 2008.
Min-cheol Gwak received his B.S. degree in Mechanical Engineering from Korea Aerospace University, Korea, in 2007. Now he is a graduate
student of Mechanical and Aerospace Engineering at Seoul National University in Seoul, Korea. His research interests are ignition
of high energy material and combustion phenomena.
Tae-yong Jung received his B.S. degree in Mechanical and Aerospace Engineering from Seoul National University, Korea, in 2007. Now he is
a graduate student of Mechanical and Aerospace Engineering at Seoul National University in Seoul, Korea. His research interests
are solid propellant combustion and phase transformation.
Professor J. Yoh received his BSME from UC Berkeley in 1992 and MSME from UCLA in 1995. His doctoral degree is in Theoretical & Applied Mechanics
from the University of Illinois at Urbana-Champaign, 2001. His research interest is in high energy system design using high
power lasers and condensed energetic materials. 相似文献
13.
Yong-Woo Kim 《Journal of Mechanical Science and Technology》2009,23(5):1294-1305
The rotational stiffness of a radial tire is one of the most important structural properties of the sidewall, and it has been
evaluated conventionally by using a simplified model. However, in this paper, it is found that the conventional shear modulus
used for the calculation of the stiffness is not micromechanically consistent. We examine the conventional shear modulus of
the sidewall from the viewpoint of micromechanics, and present a new micromechanically consistent shear modulus for evaluating
the rotational stiffness attributed to the shear deformation of sidewall. The developed method is discussed and rationalized
through an approximate quantitative analysis. The calculation based on the micromechanically consistent shear modulus is validated
by comparing it with experimental stiffness and the conventionally-calculated stiffness.
This paper was recommended for publication in revised form by Associate Editor Jeong Sam Han
Yong-Woo Kim received his Bachelor degree in Mechanical Engineering from Yonsei University, Seoul, Korea, in 1982, and his Ph.D. degree
from Yonsei Graduate School in 1991. Dr. Kim is currently Professor at Department of Mechanical Engineering at Sunchon National
University in Sunchon, Korea. Dr. Kim’s research interests include structural analysis, machine design, and tire mechanics. 相似文献
14.
Dongchoul Kim 《Journal of Mechanical Science and Technology》2009,23(2):489-497
This paper proposes a three-dimensional model for the evolution of micro and sub-micro scale flip chip solder joints. The
coupled mechanisms of electromigration and the corresponding stress gradient are incorporated into a diffuse interface model.
A semi-implicit Fourier spectral method and the preconditioned biconjugate-gradient method are proposed for the computation
to achieve high efficiency and numerical stability. Our simulations demonstrate dynamic evolution of solder joints and breakages
at the interface on the cathode side. It is also shown that the dynamically incorporated stress gradient considerably affects
the evolution of solder joints counteracting the electromigration process.
This paper was recommended for publication in revised form by Associate Editor Jeonghoon Yoo
Dongchoul Kim received a B.S. degree in Mechanical Engineering from Yonsei University in 2000. He then went on to receive his M.S. and
Ph.D. degrees from The University of Michigan in 2003 and 2005, respectively. Dr. Kim is currently an Assistant Professor
at the School of Mechanical Engineering at Sogang University in Seoul, Korea. His research interests are in the area of computational
analysis of micro/nanostructures. 相似文献
15.
Taewoong Lim Jaeik Jeong Jaewon Chung Jin Taek Chung 《Journal of Mechanical Science and Technology》2009,23(7):1788-1794
In this work, the evaporation phenomena of 20–45 picoliter water droplet (i.e. 50–65 μm diameter) on heated substrates with
different thermal conductivity are studied experimentally. The effect of thermal conductivity of substrates and inter-distance
between jetted droplets on the evaporation is investigated. In addition, the model to predict evaporation rate of the picoliter
droplet on different substrates at a heated condition is developed using approximations for picoliter droplet.
This paper was presented at the 7th JSME-KSME Thermal and Fluids Engineering Conference, Sapporo, Japan, October 2008.
Taewoong Lim received his B.S and M.S. degree in mechanical engineering from Korea University, Seoul, Korea in 2007 and 2009, respectively.
His thesis topic was the evaporation of inkjet printed pico-liter droplet and He has been working at Hyundai Motor Company.
Jaeik Jeong received his B.S. degree in mechanical engineering from Korea University in 2008. He is currently a M.S. candidate in mechanical
engineering at Korea University.
Jaewon Chung received his B.S. and M.S. degrees in mechanical engineering from Yonsei University, Seoul, Korea in 1995 and 1997, respectively
and Ph.D. degree from University of California, Berkley in 2002. He was postdoctoral associate in Engineering System Research
Center at University of California, Berkley in 2002–2004 and had worked in the Center of Micro and Nano Technology at Lawrence
Livermore National Laboratory as a visiting collaborator. He is a currently an associate professor at the Department of Mechanical
Engineering at Korea University in Seoul, Korea. His research interests include direct writing methods including drop on demand
inkjet printing, electrohydrodynamic printing and laser material processing for printing electronics.
Jin Taek Chung received his B.S. and M.S. degrees in mechanical engineering from Korea University, Seoul, Korea in 1983 and 1985, respectively
and Ph. D. degree from University of Minnesota, U.S.A. in 1992. He is a currently a professor at the Department of Mechanical
Engineering at Korea University in Seoul, Korea. His research interests are heat transfer and 3-D flow in gas turbines and
thermal management of electronic devices. 相似文献
16.
Young Chul Kwon Dae Hoon Kim Jae Heon Lee Jun Young Choi Sang Jae Lee 《Journal of Mechanical Science and Technology》2009,23(3):698-706
This paper presents the heat transfer characteristics of the internal heat exchanger (IHX) for CO2 heat pump system. The influence on the IHX length, the mass flow rate, the shape of IHX, the operating condition, and the
oil concentration was investigated under a cooling condition. Four kinds of IHX with a coaxial type and a micro-channel type,
a mass flow meter, a pump, and a measurement system. With increasing of the IHX length, the capacity, the effectiveness, and
the pressure drop increased. For the mass flow rate, the capacity of micro-channel IHX are higher about 2 times than those
of coaxial IHX. The pressure drop was larger at cold-side than at hot-side. In the transcritical CO2 cycle, system performance is very sensitive to the IHX design. Design parameters are closely related with the capacity and
the pressure drop of CO2 heat pump system. Along the operating condition, the performance of CO2 IHXs is different remarkably. For oil concentration 1, 3, 5%, the capacity decreases and the pressure drop increased, as
compared with oil concentration 0%.
This paper was recommended for publication in revised form by Associate Editor Yong Tae Kang
Prof. Young-Chul Kwon received his B.S. degree in Precision Mechanical Engineering from Pusan National University, Korea, in 1989. He then received
his M.S. and Ph.D. degrees from POSTECH, in 1991 and 1996, respectively. Dr. Kwon is currently a Professor at the Division
of Mechanical Engineering at Sunmoon University in Chungnam, Korea. He serves as a chief of the Institute of Automation and
Energy Technology. Dr. Kwon’s research interests include heat exchanger, CO2 cycle, heat pump, and energy recovery ventilator for HVAC&R.
Mr. Dae-Hoon Kim is currently Doctoral student at the Mechanical Engineering from Hanyang University in Seoul, Korea. His research topics
include experimental and numerical of CO2 heatpump system. He has conducted a study on the Analysis of Refrigerating & Air-Conditioning Equipment Industry and Its
Forecasting Supervising and Testing for Performance of Refrigerator, Freezer and Air-Conditioner.
Prof. Jae-Heon Lee received his B.S. degree in Mechanical Engineering from Seoul National University, Korea, in 1971. He then received his M.S.
and Ph. D. degree from Seoul National University in 1977 and 1980, respectively. Dr. Lee is currently a Professor at the school
of Mechanical Engineering at Hanyang University in Seoul, Korea. Dr. Lee is currently a president at the Korea Institute research
interests include simulation of thermal fluid and Plant engineering and construction.
Dr. Jun-Young Choi received his B.S. degree in Mechanical Engineering from Yonsei University, Republic of Korea, in 1989. He then received his
M.S. and Ph. D. degrees from Yonsei University in 1991 and 1999, respectively. Dr. Choi is currently a chief researcher with
the 18 years experience on the energy performance testing of HVAC/R product. He is now assigned to the Energy Technology Center
at Basic Industry Division at Korea Testing Laboratory. He has been involved in the development of Design and Manufacturing
Technology for Air-Conditioner E.E.R. and Performance Testing Equipment for Cooling and Heating System with Non-CFCs, and
natural refrigerants. He has conducted a study on the Analysis of Refrigerating & Air-Conditioning Equipment Industry and
Its Forecasting Supervising and Testing for Performance of Refrigerator, Freezer and Air-Conditioner.
Dr. Sang Jae Lee received his Ph.D. degree in Mechanical Engineering from Hanyang University, KOREA, in 2008. Dr. Lee is currently a Researcher
at the Korea Institute of Industrial Technology in Cheonan, Korea. Dr. Lee’s research interests CO2 heatpump system, liquid desiccant air conditioning system and Micro heat exchanger. 相似文献
17.
Dongchoul Kim 《Journal of Mechanical Science and Technology》2009,23(2):504-511
Recent experiments have shown failure in flip chip micro solder joints induced by electromigration. This paper proposes a
computational model to simulate the evolution of micro and sub-micro scale solder joints due to electromigration induced diffusion.
Complicated morphological changes of the solder bump and multiple mechanisms cause a computational challenge. This is addressed
by employing a diffuse interface model with multiple concentrations. To efficiently resolve complications, a semi-implicit
Fourier spectral scheme and a biconjugate-gradient method are adopted. Results have demonstrated rich dynamics and solder
breakage at the interface on the cathode side.
This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim
Dongchoul Kim received a B.S. degree in Mechanical Engineering from Yonsei University in 2000. He then went on to receive his M.S. and
Ph.D. degrees from The University of Michigan in 2003 and 2005, respectively. Dr. Kim is currently an Assistant Professor
at the School of Mechanical Engineering at Sogang University in Seoul, Korea. Dr. Kim’s research interests are in the area
of computational analysis of micro/nanostructures. 相似文献
18.
Kyung-Hyun Choi Hyung-Chan Kim Yang-Hoi Doh Dong-Soo Kim 《Journal of Mechanical Science and Technology》2009,23(4):1102-1111
A solid freeform fabrication (SFF) system using selective laser sintering (SLS) is currently recognized as a leading process
of fabrication using variable materials, and SLS extends the application to machinery and automobiles. Due to the time delay
in the sintering process, shrinkage and warping often occur. Curling also occurs due to laser and scan delays. These problems
affect not only the accuracy of the fabricated product but also the total system efficiency. These deficiencies can be overcome
by reducing the total processing time of the SFF system. To accomplish this, the laser scanning time, from mark (laser on)
to jump (laser off), must be reduced as it contributes the major part of the total processing time. This can be done by employing
area division scan path generation, which promotes digital efficiency. A simulation and an experiment was carried out in this
study to evaluate the developed scan path method.
This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim
Kyung-Hyun Choi received his B.S. and M.S. degrees in Mechanical Engineering from Pusan National University, Korea, in 1983 and 1990,. He
then received his M.S. and Ph.D. degrees from University of Ottawa in 1995. Dr. Choi is currently a professor at the School
of Mechanical Engineering at Cheju National University, Korea. His research interests include micro-machining, printed Electronics.
Hyung-Chan Kim received his B. S. and M. S. degrees in Electronics Engineering from Cheju National University, Korea, in 2006 and 2008,
respectively. Mr. Kim is currently a Ph.D. candidate at the School of Electronics Engineering at Cheju National University,
Korea. His research interests include RP System, micro-machining, printed Electronics.
Yang-Hoi Doh received his B.S. and M.S. degrees in Electronics Engineering from KyungBuk National University, Korea, in 1982 and 1984,
respectively. He then received his Ph.D. degree from University of Kyung Buk National University, Korea, in 1988. Dr. Doh
is currently a Professor at the School of Electronics Engineering at Cheju National University, Korea. His research interests
include micro-machining, Digital signal processing.
Dong-Soo Kim received his M.S. and Ph.D. degrees in Mechanical Engineering from Yung Nam University, Korea, in 1991 and 2001, respectively.
Dr. Kim is currently the general manager at Nano Mechanical System Research Division at Korea Institute of Machinery & Materials.
His research interests include printed Electronics, R2R printing, RP system. 相似文献
19.
Seok-Heum Baek Seok-Swoo Cho Hyun-Su Kim Won-Sik Joo 《Journal of Mechanical Science and Technology》2009,23(5):1225-1233
As the cumulative running times of a locomotive truck increases, degradation such as fatigue, wear, and deterioration occur.
Particularly the container train and uncovered freight train, their maintenance cost during their lifetime is three times
more than the manufacturing cost. Generally, for the freight train, corrective maintenance to repair a bad part after a breakdown
is not adapted; however, preventive maintenance that fixes a bad part before a breakdown is. Therefore, it is important and
necessary to establish a system of optimal preventive maintenance and exact maintenance period. This study attempts to propose
a preventive maintenance procedure that predicts a repair period using reliability function and instantaneous failure rate
based on fatigue test and load history data. Additionally, this method is applied to the end beam of an uncovered freight
train, which is the brake part, and its usefulness is examined and analyzed.
This paper was recommended for publication in revised form by Associate Editor Chongdu Cho
Seok-Heum Baek received a B.S. and M.S. degree in Mechanical Engineering from the Dong-A University in 2001 and 2003, respectively. He is
currently a Ph.D. student at the School of Mechanical Engineering at Dong-A University in Busan, Korea. Student Baek works
on ceramic composite design and robust and reliability-based design, and his research interests are in the areas of trade-off
analysis in multicriteria optimization, design under uncertainty with incomplete information, and probabilistic design optimization.
Seok-Swoo Cho received a B.S. degree in Mechanical Engineering from Dong-A University in 1991. He then went on to receive his M.S. from
Dong-A University in 1993 and Ph.D. degree from Dong-A University in 1997. Dr. Cho is currently a Professor at the Vehicle
Engineering at Kangwon National University in Kangwon-do, Korea. Dr. Cho works on crack growth modeling and composite design
and optimization, and his research interests are in the areas of structural optimization and inverse and identification problems,
and X-ray diffraction, brittle collapse and crack propagation, fatigue fracture phenomena.
Hyun-Su Kim received a B.S. degree in Mechanical Engineering from Seoul National University in 1978. He then went on to receive his M.S.
from KAIST in 1980 and Ph.D. degree from University of Iowa in 1989. Dr. Kim is currently a Professor at the Mechanical Engineering
at Dong-A University in Busan, Korea. His research interests are in the area of high temperature creep fatigue, bio-engineering,
design using the finite element method, optimization, and MEMS.
Won-Sik Joo received a B.S. degree in Mechanical Engineering from Dong-A University in 1968. He then went on to receive his M.S. from
Dong-A University in 1978 and Ph.D. degree from Kookmin University in 1988. Dr. Joo is currently a Professor at the Mechanical
Engineering at Dong-A University in Busan, Korea. His research interests are in the area of creep and fatigue in high temperature
alloy, fatigue design, and strength evaluation. 相似文献
20.
Micro machining of an STS 304 bar by magnetic abrasive finishing 总被引:1,自引:0,他引:1
Ik-Tae Im Sang Don Mun Seong Mo Oh 《Journal of Mechanical Science and Technology》2009,23(7):1982-1988
A magnetic abrasive finishing process is a method of non-traditional precision machining in which the finishing process is
completed using magnetic force and magnetic abrasives. In this research, a STS 304 cylindrical workpiece was finished using
a magnetic abrasive finishing process at 30,000 rpm, and the roughness, roundness, and changes in the micro-diameter were
investigated. The study showed that it is possible to control the micro-diameter and weight of the STS 304 cylindrical workpiece
by using a near linear approach. Surface roughness as fine as 0.06 μm (Ry) and roundness as fine as 0.12 μm (LZS) were achievable
by using a diamond paste with 1 μm particles. Vibrational motion applied to the workpiece improved the surface roughness.
The improvement of the surface roughness was achieved because the vibrational motion effectively removes unevenness in the
rotational direction and the direction orthogonal to it.
This paper was presented at the 9th Asian International Conference on Fluid Machinery (AICFM9), Jeju, Korea, October 16–19, 2007.recommended for publication
in revised form by Associate Editor Dae-Eun Kim
Ik-Tae Im received the B.S., M.S. and Ph.D. degrees in Mechanical Engineering from Hanyang University, Seoul, Korea, in 1993, 1995
and 1999, respectively. He has been a visiting scientist at the Department of Materials Engineering, the University of Tokyo,
Japan, where he studied on the film growth during the MOCVD process. His research interests include the numerical modeling
on the transport phenomena in various materials processing. He is a professor at the Division of Mechanical Design Engineering
at Chonbuk National University in Jeonju, Korea.
Sang Don Mun received the B.S. degree and M.S. in Precision Mechanical Engineering from Chonbuk National University, Korea, in 1991 and
1993, respectively. He then received the Ph.D. in Precision Mechanical Engineering at the same university in 1997. Dr. Mun
is currently a Professor at the Division of Mechanical Design Engineering at Chonbuk National University in Jeonju, Korea.
His research interests include magnetic abrasive finishing, tool wear, and micro machining.
Seong Mo Oh received his B.S. degree in Mechanical Engineering from Wonkwang University, Korea, in 1992. He then received his M.S. and
Ph.D. degrees from Wonkwang in 1994 and 2000 respectively. Dr. Oh is currently a Lecturer at the Division of Mechanical and
Automotive Engineering at Wonkwang University in Jeonbuk, Korea. Dr. Oh’s research interests include tribology, functional
surfaces, and micromachining. 相似文献