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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society of Mechanical Engineers B
Journal Basic Information
Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 34, Issue 12 - Dec 2010
Volume 34, Issue 11 - Nov 2010
Volume 34, Issue 10 - Oct 2010
Volume 34, Issue 9 - Sep 2010
Volume 34, Issue 8 - Aug 2010
Volume 34, Issue 7 - Jul 2010
Volume 34, Issue 6 - Jun 2010
Volume 34, Issue 5 - May 2010
Volume 34, Issue 4 - Apr 2010
Volume 34, Issue 3 - Mar 2010
Volume 34, Issue 2 - Feb 2010
Volume 34, Issue 1 - Jan 2010
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Modeling of Damage Caused to Injectors Used in Pulverized-Coal-Oxygen-Combustion Furnace
Gwak, Min-Cheol ; Kwon, Ki-Woong ; Lee, Sang-Ho ; Yoh, Jai-Ick ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 11, 2010, Pages 957~964
DOI : 10.3795/KSME-B.2010.34.11.957
The deflagration-to-detonation transition (DDT) causes a strong pressure wave that can adversely affect surrounding structures. The pressure generated by multiple detonative pulses is strong enough to cause metal surface erosion and chipping of the edges of bulk structures. In this study, we investigate the damage caused by the DDT phenomenon and perform hydrocode simulations to evaluate the structural damage caused to a metallic pulverized-coal injector used in a pulverized-coal-oxygen combustion furnace. The experimental conditions are selected in order to accurately model the damage caused to metal injectors that are exposed to multiple DDT pulses.
Investigation of Flow and Heat Transfer Characteristics of Plate Heat Exchanger Taking into Account Entrance Effects and Variation in Corrugation Height
Moh, Jeong-Hah ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 11, 2010, Pages 965~973
DOI : 10.3795/KSME-B.2010.34.11.965
Numerical analysis has been carried out to investigate the heat transfer characteristics of a plate heat exchanger. The multi-cell models with inlet part and outlet part are used for performing numerical simulation. The plate heat exchanger is characterized by chevron angle of
, corrugation pitch of 24mm and corrugation height 6~12mm. The length of the inlet-part considered in the analysis ranges from 24.8 to 124mm and Reynolds numbers range from 1,000 to 10,000. The correlations such as friction factor and Colburn factor are compared with previous experimental data. The results can be utilized for designing the plate heat exchanger.
Laser Sintering of Inkjet-Printed Silver Lines on Glass and PET Substrates
Kim, Myong-Ki ; Kang, Heui-Seok ; Kang, Kyung-Tae ; Lee, Sang-Ho ; Hwang, Jun-Young ; Moon, Seung-Jae ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 11, 2010, Pages 975~982
DOI : 10.3795/KSME-B.2010.34.11.975
In this study, the laser sintering of inkjet-printed silver lines was evaluated. Silver-nanoparticle ink and a drop-ondemand (DOD) inkjet printer were used for printing on glass and polyethylene terephthalate (PET) substrates with various thicknesses. To sinter the printed silver nanoparticles, the silver layer printed on the transparent substrates was irradiated by focused CW laser beams that were incident normal to the substrates; the irradiation was carried out for various beam intensities and for various irradiation times. The electrical conductivity of the laser-sintered silver patterns was measured and compared with the conductivity of silver patterns sintered by using an oven. The increase in the temperature caused by laser irradiation was also calculated on the basis of the laser beam intensity, irradiation time, surface reflectivity, and thermophysical property of the substrate in order to estimate the increase in the electrical conductivity caused by laser sintering.
Effects of Micro-fin Structure on Spray Cooling Heat Transfer in Forced Convection and Nucleate Boiling Region
Kim, Yeung-Chan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 11, 2010, Pages 983~990
DOI : 10.3795/KSME-B.2010.34.11.983
In the present study, spray cooling heat transfer was experimentally investigated for the case in which water is sprayed onto the surfaces of micro-fins in forced convection and nucleate boiling regions. The experimental results show that an increase in the droplet flow rate improves heat transfer due to forced convection and nucleate boiling in the both case of smooth surface and surfaces of micro-fins. However, the effect of subcooling for fixed droplet flow rate is very weak. Micro-fins surfaces enhance the spray cooling heat transfer significantly. In the dilute spray region, the micro-fin structure has a significant effect on the spray cooling heat transfer. However, this effect is weak in the dense spray region. A previously determined correlation between the Nusselt number and Reynolds number shows good agreement with the present experimental data for a smooth surface.
Analysis of Transient Performance of KALIMER-600 Reactor Pool by Changing the Elevation of Intermediate Heat Exchanger
Han, Ji-Woong ; Eoh, Jae-Hyuk ; Kim, Seong-O ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 11, 2010, Pages 991~998
DOI : 10.3795/KSME-B.2010.34.11.991
The effect of increasing the elevation of an IHX (intermediate heat exchanger) on the transient performance of the KALIMER-600 reactor pool during the early phase of a loss of normal heat sink accident was investigated. Three reactors equipped with IHXs that were elevated to different heights were designed, and the thermal-hydraulic analyses were carried out for the steady and transient state by using the COMMIX-1AR/P code. In order to analyze the effects of the elevation of an IHX between reactors, various thermal-hydraulic properties such as mass flow rate, core peak temperature, RmfQ (ratio of mass flow over Q) and initiation time of decay heat removal via DHX (decay heat exchanger) were evaluated. It was found that with an increase in the IHX elevation, the circulation flow rate increases and a steep rise in the core peak temperature under the same coastdown flow condition is prevented without a delay in the initiation of the second stage of cooling. The available coastdown flow range in the reactor could be increased by increasing the elevation of the IHX.
The Spray Characteristics and Spray Behavior Characteristic in Exhaust Gas Flow of Urea Solution Injector
Oh, Jung-Mo ; Han, Young-Deok ; Kim, Ki-Bum ; Lee, Ki-Hyung ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 11, 2010, Pages 999~1004
DOI : 10.3795/KSME-B.2010.34.11.999
Recently, many technologies have been developed in order to satisfy stringent emission regulations. However, in the case of diesel engines, the stringent emission regulations with respect to NOx and PM have not yet been satisfied. A dramatic reduction in the NOx and PM emissions could be achieved by using after-treatment systems such as lean NOx trap (LNT) and urea-SCR systems. However, the high temperature in the exhaust pipe affects the spray behavior of the secondary injector, which is used for supplying the Urea-SCR. Because of this high temperature, it is difficult to achieve uniform distribution of the reducing agent in the manifold. In this paper, the characteristics of a urea-SCR injector used for injecting in the exhaust pipe are presented. The purpose of this study was to investigate the spray characteristics of the injector, such as the spray angle, injection quantity, and SMD. In addition, laser diagnostics and high-speed-camera images were used to analyze the injector spray characteristics and to present a distribution of reduction in the transparent manifold.
Study on the Spray Control of Mixed Fuel Using Flash Boiling
Myong, Kwang-Jae ; Yoon, Jun-Kyu ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 11, 2010, Pages 1005~1013
DOI : 10.3795/KSME-B.2010.34.11.1005
This study was conducted to assess the spray control of flash boiling with mixed fuel in consideration of HCCI (Homogeneous Charge Compression Ignition) engine condition. Mixed fuel existing in two phase regions can control the process of mixture formation under low temperature and density by using the spray resulting from flash boiling which is able to induce rapid evaporation of fuel spray as well as the evaporation of high boiling point component. Because HCCI engine injects the fuel early under ambient conditions, it can facilitate the chemical control of ignition combustion and physical control such as breakup and atomization of liquid fuel by flash boiling of mixed fuel which consists of highly ignitable light oil and highly volatile gasoline. This study was conducted by performing video processing after selected composition and molar fraction of the mixed fuel as major parameters and photographed Schlieren image and Mie scattered light corresponding to the flash boiling phenomenon of the fuel spray that was injected inside a constant volume vessel. It was found that flash boiling causes significant changes in the spray structure under relatively low temperature and density. Thus, we analyzed that the flash boiling spray can be used for HCCI combustion by controlling the mixture formation at the early fuel injection timing.
Experimental Study on the Effects of AC Electric Fields on Flame Spreading over Polyethylene-insulated Electric-Wire
Jin, Young-Kyu ; Kim, Min-Kuk ; Park, Jeong ; Chung, Suk-Ho ; Kim, Tae-Hyung ; Park, Jong-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 11, 2010, Pages 1015~1025
DOI : 10.3795/KSME-B.2010.34.11.1015
In this present study, we experimentally investigated the effects of electric fields on the characteristics of flames spreading over electric-wires with AC fields. The dependence of the rate at which a flame spreads over polyethylene-insulated wires on the frequency and amplitude of the applied AC electric field was examined. The spreading of the flame can be categorized into linear spreading and non-linearly accelerated spreading of flame. This categorization is based on the axial distribution of the field strength of the applied electric field. The rate at which the flame spreads is highly dependent on the inclined direction of the wire fire. It could be possible to explain the spreading of the flame on the basis of thermal balance.
Experimental Study of Characteristics of Three-Ring Impedance Meter and Dependence of Characteristics on Electric Conductivity of Fluids
Kim, Jong-Rok ; Ahn, Yeh-Chan ; Kim, Moo-Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 11, 2010, Pages 1027~1033
DOI : 10.3795/KSME-B.2010.34.11.1027
A two-phase (gas-liquid) flow is a common phenomenon in fluidic systems, e.g., fluidic systems in the electro-magnetic or nuclear power generation industry and in the steel industry. The measurement of a two-phase flow is important for guaranteeing the safety of the system and for achieving the desired performance. The measurement of the void fraction, which is one of the parameters of the two-phase flow that determines the pressure drop and heat transfer coefficient, is very important. The time resolution achieved by employing the impedance method that can be used to calculate the void fraction from the impedance of the fluid is high because the electric characteristics are taken into account. Therefore, this method can be employed to accurately measure the void fraction without distortion of flow in real time by placing electrodes on the walls of the tubes. Coney analytically studied a ring-type impedance meter, which can be employed in a circular tube. The aim of this study is to experimentally verify the robustness of a three-ring impedance meter to variations in the electric conductivity of the fluid; this robustness was suggested by Coney but was not experimentally verified.