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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
Editor in Chief :
Volume & Issues
Volume 37, Issue 12 - Dec 2013
Volume 37, Issue 11 - Nov 2013
Volume 37, Issue 10 - Oct 2013
Volume 37, Issue 9 - Sep 2013
Volume 37, Issue 8 - Aug 2013
Volume 37, Issue 7 - Jul 2013
Volume 37, Issue 6 - Jun 2013
Volume 37, Issue 5 - May 2013
Volume 37, Issue 4 - Apr 2013
Volume 37, Issue 3 - Mar 2013
Volume 37, Issue 2 - Feb 2013
Volume 37, Issue 1 - Jan 2013
Selecting the target year
Long-Term Experiments of Cooling/Cleaning on Surface of 200-kW PV Power Array
Han, Jun Sun ; Jeong, Seong Dae ; Yu, Sang Phil ; Lee, Seong Su ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 971~975
DOI : 10.3795/KSME-B.2013.37.11.971
In general, the solar photovoltaic power increases with higher solar insolation. However, the solar cell generation efficiency reduces because the solar cell surface is heated by solar insolation. According to advanced research, with a
increase in the solar cell surface temperature, the generation efficiency decreases by ~0.5%. To solve this problem, we conducted experiments in which we attempted to reduce the solar cell surface temperature using a water jet spray. In this study, we found the long-term experimental results of increases in solar power generation. The experimental results show a comparison of the site with and without cooling and cleaning equipment being installed. The results of the long-term experiments show that solar photovoltaic power generation is increased by at least 13% up to 19% with cooling and cleaning.
Heat and Mass Transfer in Hygroscopic Rotor During Adsorption and Desorption Process
Shin, Hyun-Geun ; Park, Il Seouk ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 977~984
DOI : 10.3795/KSME-B.2013.37.11.977
A hygroscopic rotor comprises many microchannels with high adsorption characteristics. In this study, the iterative adsorption/desorption processes that were affected by the humid air flow in a channel were numerically simulated. In consideration of the accuracy and computational costs, in the desiccant layer, only surface diffusion was considered in this simulation. The results were compared with the previous numerical results and found to show good agreement. By conjugating the heat and mass transfer between the desiccant and the flow layers, temporal and spatial changes in the vapor mass fraction, adsorbed liquid water mass fraction, and temperature in the channel were presented.
Flow Visualization of Arteriovenous Grafting Using PIV Technique
Jeon, Min-Gyu ; Kim, Hyoung-Ho ; Suh, Sang-Ho ; Choi, Young Ho ; Lee, Hyun-Jin ; Doh, Deog-Hee ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 985~990
DOI : 10.3795/KSME-B.2013.37.11.985
An arteriovenous fistula is artificially produced using a graft for hemodialysis in patients. In an arteriovenous graft (AVG), the angle of its arterial or venous anastomosis play an important role in producing flows inside blood vessels, through which a stenosis may occur. Most studies thus far have focused on CFD results. In this study, a PIV technique is used to analyze the hemodynamic characteristics at the arterial or venous anastomosis of an AVG having an angle of
. For flow dynamic similarity, the Reynolds number is set to be the same for real and simulated flows. A PIV experiment is performed with a control valve in the arterial part. In conclusion, the recirculation flow appeared in the bifurcation area and the total blood velocity changed according to the extent of valve opening.
Effect of Variation of Heated Bottom Wall Area on Natural Convection in Square Enclosure with Inner Circular Cylinder
Jo, Hyun Woo ; Yoon, Hyun Sik ; Lee, Hyo Jeong ; Kim, Minsung ; Ha, Man Yeong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 991~998
DOI : 10.3795/KSME-B.2013.37.11.991
A numerical study is carried out for natural convection in an enclosure with an inner hot cylinder at the center. The top wall is cold, the bottom and both side walls of the enclosure are adiabatic, and the cylinder is heated. The bottom wall is heated locally at the middle. The ratio (w) is defined by as the width of the bottom wall to that of the heated local area. The immersed boundary method (IBM) is used to model an inner circular cylinder based on the finite volume method (FVM). This study investigates the effect of w on natural convection in an enclosure with an inner heated cylinder for Rayleigh numbers of
, thermal and flow fields show time-dependent characteristics after their full development.
Numerical Study on Flow and Heat Transfer Characteristics of Pipes with Various Shapes
Park, Sang Hyeop ; Kim, Sang Keun ; Ha, Man Yeong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 999~1007
DOI : 10.3795/KSME-B.2013.37.11.999
The present work reports numerical results of the pressure drop and heat transfer characteristics of pipes with various shapes such as circular, elliptical, circumferential wavy and twisted using a three-dimensional simulation. Numerical simulations are calculated for laminar to turbulent flows. The fully developed flow in pipes was modeled using steady incompressible Reynolds-averaged Navier-Stokes (RANS) equations. The friction and Colburn factor of each pipe are compared with those of a circular tube. The overall flow and heat transfer calculations are evaluated by the volume and area goodness factor. Finally, the objective of the investigation is to find a pipe shape that decreases the pressure loss and increases the heat transfer coefficient.
Experimental Study on Transient Response According to Variation of Rib Height at Fuel Cell Plate
Nam, Ki Hoon ; Yun, Sung Ho ; Han, Sung Ho ; Choi, Nam Hyeon ; Choi, Young Don ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 1009~1014
DOI : 10.3795/KSME-B.2013.37.11.1009
In the present study, using a variation of rib height, the transient response and the performance are investigated. The cell voltage is acquired according to the current density change(
) under same stoichiometry and relative humidity. The different level of undershoots appeared at the different clamping pressure(1.5MPa and 2.0MPa) and different rib height. At 1.5MPa clamping pressure, rib manufactured cut at
height goes to steady state faster than reference plate and has lower maximum undershoot voltage. But performance is lower than reference plate due to increasing contact resistance.
Analysis of Operating Characteristics of 200kW Class Micro Gas Turbine
Kim, Jeong Ho ; Kang, Do Won ; Kim, Tong Seop ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 1015~1022
DOI : 10.3795/KSME-B.2013.37.11.1015
This study simulates the operation of a 200 kW class micro gas turbine that is currently under development. The performance and operating characteristics depending on the load control scheme (constant turbine inlet temperature versus constant turbine exit temperature) and ambient condition were investigated using detailed component performance data. The sensitivities of operating parameters, such as the compressor surge margin and flow path temperatures, according to unit fuel flow change were predicted for a wide load range. The sensitivity analysis showed that the steady state calculation provided useful information about the maximum surge margin reduction during load change.
Performance Analysis of IGCC Gas Turbine Considering Turbine Operation Condition Change due to Modulation of Nitrogen Dilution
Kim, Chang Min ; Kang, Do Won ; Kim, Tong Seop ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 1023~1029
DOI : 10.3795/KSME-B.2013.37.11.1023
The integration between a gas turbine and an air separation unit (ASU) is important in IGCC plants. The portion of ASU air extracted from the gas turbine and the degree of nitrogen supply from the ASU to the gas turbine side are important operating parameters. Their effect on the gas turbine performance and operability should be considered in a wide ambient temperature range. In this study, appropriate nitrogen dilution rate and turbine inlet temperature that satisfy the two limitations of turbine blade temperature and maximum allowable power output were predicted. The air integration was set at zero. The simulation showed that the power output increases and turbine blade temperature decreases as the nitrogen dilution increases. The maximum allowable power output can be obtained under medium and low ambient temperature ranges. Under a high ambient temperature range, the achievable power is less than the maximum power.
Development of a New Water Circulating System for Hot Water Mattress Without Water Pump
Je, Jong Joo ; Sohn, Chang Hyun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 1031~1036
DOI : 10.3795/KSME-B.2013.37.11.1031
The motor-driven water pump boiler for a water circulating mattress generates noise and vibration as it supplies a large water flow rate. A non-pump boiler can reduce such noise and vibration, however, the water circulation flow rate becomes lesser than that in motor-driven water pump boilers, and a large temperature deviation occurs between the inlet and the outlet of the mattress. In this research, a new non-pump boiler for water circulating mattress is developed and its performance is experimentally validated and compared with the existing non-pump boilers. The experimental results show that temperature response time is improved and temperature deviation is reduced.
Correlation Analysis of Flow Characteristics Downstream of a Double Bent Pipe and Mounting Positions of Ultrasonic Flowmeter
Lee, Dong Keun ; Cho, Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 1037~1046
DOI : 10.3795/KSME-B.2013.37.11.1037
In this study, the establishment of the criteria for accurate measurement is investigated via a statistical analysis of experimental results. The magnitude of influence on measurement errors is severely affected by the number of paths, mounting angle of sensor, straight pipe length in sequence, and Reynolds number. Three-dimensional numerical analysis has been conducted to understand the flow patterns downstream of a double bent pipe. Numerical analysis shows that the results well agreed with the experimental ones in case of a sensor mounting angle of
and L/D = 3, 5 of
in a single path. As a result, when the Reynolds number is 700,000-1,400,000, the sensor error of a single-path ultrasonic flowmeter is reduced with the mounting condition of L/D = 3,
Optimized Design of Air Controlling System in Air Defense Gun Systems of Wheeled Vehicle
Jeon, Ki-Hyun ; Lee, Boo-Hwan ; Lee, Dong-Hee ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 1047~1051
DOI : 10.3795/KSME-B.2013.37.11.1047
A modern combat vehicle needs to have a separate air-conditioning unit, although new combat systems tend to employ an integrated heating, cooling, and ventilating system. In this study, we investigated an air conditioning unit for an armored combat wheeled vehicle as a special use and military specification and performed a case study of a unique military combat vehicle. By using Fluent software, we tried to determine a suitable air ducting method and its location in the armored combat vehicle. The results show that an air-conditioning unit is one of the best solutions for wheeled vehicles that are not equipped with a cooling unit for their crews, and it can be applied to similar types of armored vehicles.
A Study on the Packing Friction Estimation of Power-Operated Valves in Nuclear Power Plants
Ryu, Dong Hwa ; Lee, Young Shin ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 11, 2013, Pages 1053~1060
DOI : 10.3795/KSME-B.2013.37.11.1053
The purpose of this study is to estimate the packing friction of power-operated valve in nuclear power plants. The roll of packing in valve is preventing leakage through stem. Packing friction is highly depend on gland nut tightness which means higher reliability in sealing is lower operability. For the estimation of friction, we used statistical analysis and experimental analysis. In experimental approach, we have performed packing fY test and applied it to valve field test. In statistical approach, we have used 10 years DB of safety-related valve in nuclear power plant and analyzed packing friction based on confidence interval of sample. The comparison of two results shows that statistical analysis for packing friction are more accurate than fY analysis even though both approach have error compared to measured value but we confirmed that statistical approach is proper way to estimate packing friction.