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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 40, Issue 9 - Sep 2016
Volume 40, Issue 8 - Aug 2016
Volume 40, Issue 7 - Jul 2016
Volume 40, Issue 6 - Jun 2016
Volume 40, Issue 5 - May 2016
Volume 40, Issue 4 - Apr 2016
Volume 40, Issue 3 - Mar 2016
Volume 40, Issue 2 - Feb 2016
Volume 40, Issue 1 - Jan 2016
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Numerical Investigation on the Urea Melting Characteristics with Coolant and Electric Heaters
Lee, Seung Yeop ; Kim, Man Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 40, issue 1, 2016, Pages 1~7
DOI : 10.3795/KSME-B.2016.40.1.001
A Urea-SCR(Selective Catalytic Reactor) system, which converts nitrogen oxides into nitrogen and water in the presence of a reducing agent, creates a major exhaust gas aftertreatment system for NOx reduction among other compounds. With regard to vehicle applications, a urea solution was chosen based on its eutectic composition of a 32.5wt% urea-water solution. An important advantage of this eutectic composition is that its melting point of
is sufficiently low to avoid solidification in cold environments. However, the storage tanks must be heated separately in case of low ambient temperature levels to ensure a sufficient amount of liquid is available during scheduled start ups. In this study, therefore, a numerical investigation of three-dimensional unsteady heating problems analyzed to understand the melting processes and heat transfer characteristics including liquid volume fraction, temperature distributions, and temperature profiles. The investigations were performed using Fluent 6.3 commercial software that modeled coolant and electric heater models based on a urea solution. It is shown that the melting performance with the electric heater is higher than a coolant heater and is more efficient.
Numerical Study on Fluid Flow Characteristics in Taylor Reactor using Computational Fluid Dynamics
Lee, Seung-Ho ; Shim, Kyu Hwan ; Jeon, Dong Hyup ;
Transactions of the Korean Society of Mechanical Engineers B, volume 40, issue 1, 2016, Pages 9~19
DOI : 10.3795/KSME-B.2016.40.1.009
This study investigated the variations of Taylor flow and particle residence time in a Taylor reactor according to the changes of angular velocity and inlet velocity using computational fluid dynamics technique. The results showed that the fluid in a reactor became unstable with an increase of angular velocity. The flow moved to the regions of CCF, TVF, WVF and MWVF resulting in an increase of Reynolds number. Accordingly, the flow characteristics were different for each regions. We confirmed that the inlet velocity influences the Taylor flow. The particle residence time and standard deviation increased with an increase of angular velocity and a decrease of inlet velocity.
Validation of the Eddy Viscosity and Lange Wake Models using Measured Wake Flow Characteristics Behind a Large Wind Turbine Rotor
Jeon, Sang Hyeon ; Go, Young Jun ; Kim, Bum Suk ; Huh, Jong Chul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 40, issue 1, 2016, Pages 21~29
DOI : 10.3795/KSME-B.2016.40.1.021
The wake effects behind wind turbines were investigated by using data from a Met Mast tower and the SCADA (Supervisory Control and Data Acquisition) system for a wind turbine. The results of the wake investigations and predicted values for the velocity deficit based on the eddy viscosity model were compared with the turbulence intensity from the Lange model. As a result, the velocity deficit and turbulence intensity of the wake increased as the free stream wind speed decreased. In addition, the magnitude of the velocity deficit for the center of the wake using the eddy viscosity model was overestimated while the turbulence intensity from the Lange model showed similarities with measured values.
Experimental Investigation into the Combustion Characteristics on the Co-firing of Biomass with Coal as a Function of Particle Size and Blending Ratio
Sh, Lkhagvadorj ; Kim, Sang-In ; Lim, Ho ; Lee, Byoung-Hwa ; Kim, Seung-Mo ; Jeon, Chung-Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 40, issue 1, 2016, Pages 31~37
DOI : 10.3795/KSME-B.2016.40.1.031
Co-firing of biomass with coal is a promising combustion technology in a coal-fired power plant. However, it still requires verifications to apply co-firing in an actual boiler. In this study, data from the Thermogravimetric analyzer(TGA) and Drop tube furnace(DTF) were used to obtain the combustion characteristics of biomass when co-firing with coal. The combustion characteristics were verified using experimental results including reactivity from the TGA and Unburned carbon(UBC) data from the DTF. The experiment also analyzed with the variation of the biomass blending ratio and biomass particle size. It was determined that increasing the biomass blending ratio resulted in incomplete chemical reactions due to insufficient oxygen levels because of the rapid initial combustion characteristics of the biomass. Thus, the optimum blending condition of the biomass based on the results of this study was found to be 5 while oxygen enrichment reduced the increase of UBC that occurred during combustion of blended biomass and coal.
Control Algorithm Characteristic Study of Cooling System for Automotive Fuel Cell Application.
Han, Jae Young ; Park, Ji Soo ; Yu, Sangseok ;
Transactions of the Korean Society of Mechanical Engineers B, volume 40, issue 1, 2016, Pages 39~45
DOI : 10.3795/KSME-B.2016.40.1.039
Thermal management of a fuel cell is important to satisfy the requirements of durability and efficiency under varying load conditions. In this study, a linear state feedback controller was designed to maintain the temperature within operating conditions. Due to the nonlinearity of automotive fuel cell system, the state feedback controller results in marginal stable under load condition from
. A PWM (Pulse Width Modulation) and the modified state feedback controller are applied to control the temperature under the load condition from
. The cooling system model is composed of a reservoir, radiator, bypass valve, fan, and a water pump. The performance of the control algorithm was evaluated in terms of the integral time weighted absolute error (ITAE). Additionally, MATLAB/SIMULINK
was used for the development of the system models and controllers. The modified state feedback controller was found to be more effective for controlling temperature than other algorithms when tested under low load conditions.
Effect of Mixing Ratio of Active Material on the Wettability in Lithium-Ion Battery Using Lattice Boltzmann Method
Jeon, Dong Hyup ;
Transactions of the Korean Society of Mechanical Engineers B, volume 40, issue 1, 2016, Pages 47~53
DOI : 10.3795/KSME-B.2016.40.1.047
The electrolyte wetting phenomena occurring in the electrode of lithium-ion battery was studied using lattice Boltzmann method (LBM). Recently, lithium-ion batteries are being mixed with small particles on the active material to increase the capacity and energy density during the electrode design stage. The change to the mixing ratio may influence the wettability of electrolyte. In this study, the changes in electrolyte distribution and saturation were investigated according to various mixing ratios of active material. We found that the variations in mixing ratio of active material affect the wetting mechanism, and result in changes to the wetting speed and wettability of electrolyte.
A Performance Analysis and Experiments on Plastic Film/Paper Humidifying Elements Consisting of Horizontal Air Channels and Vertical Water Channels
Kim, Nae-Hyun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 40, issue 1, 2016, Pages 55~63
DOI : 10.3795/KSME-B.2016.40.1.055
New materials and shapes for a humidifying element were developed which outperformed the widely used crisscross glass wool Glasdek media design. The new material consists of 50% cellulose and 50% PET. The parallel channel configuration was devised to reduce excessive pressure loss caused by the reduced height (from 7.0 mm to 5.0 mm) of the crisscross configuration. For the same crisscross configuration, the humidification efficiency of the cellulose/PET element was 26% higher than that of the glass wool element. For the same cellulose/PET material, humidification efficiency of the parallel channel configuration was 14% higher than that of the crisscross configuration. As for the pressure drops, the cellulose/PET element was 2-52% higher than those of the glass wool element. For the same cellulose/PET material, the pressure drop of the parallel channel configuration was 14% higher than that of the crisscross configuration. Data were compared against the predictions from existing correlations and those by the proposed model.