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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
Aerodynamic Rig Test of Radial Turbine for APU
Kang, Jeong-Seek ; Lim, Byeung-Jun ; Ahn, Iee-Ki ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 1~7
DOI : 10.3795/KSME-B.2013.37.1.001
An aerodynamic rig test of a radial turbine for an auxiliary power unit (APU) was performed at a high-temperature turbine test facility at the Korea Aerospace Research Institute. The pressure ratio, Mach number, and flow coefficient in the rig test are the same as those under normal engine operation conditions. The design pressure ratio is 3.096, design test speed is 34909 rpm, and turbine inlet temperature is
. The turbine has airfoil-type nozzles, and the diameter of the turbine wheel is 175.74 mm. The turbine map is experimentally measured, and the detailed flow at the turbine inlet is measured. The pressure distribution in the nozzle at both the hub and the shroud sides and the pressure distribution along the shroud casing of the turbine wheel were measured, and this confirmed that the expansion process in the turbine wheel is acceptable.
Pressure Distribution over Tube Surfaces of Tube Bundle Subjected to Two-Phase Cross-Flow
Sim, Woo Gun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 9~18
DOI : 10.3795/KSME-B.2013.37.1.009
Two-phase vapor-liquid flows exist in many shell and tube heat exchangers such as condensers, evaporators, and nuclear steam generators. To understand the fluid dynamic forces acting on a structure subjected to a two-phase flow, it is essential to obtain detailed information about the characteristics of a two-phase flow. The characteristics of a two-phase flow and the flow parameters were introduced, and then, an experiment was performed to evaluate the pressure loss in the tube bundles and the fluid-dynamic force acting on the cylinder owing to the pressure distribution. A two-phase flow was pre-mixed at the entrance of the test section, and the experiments were undertaken using a normal triangular array of cylinders subjected to a two-phase cross-flow. The pressure loss along the flow direction in the tube bundles was measured to calculate the two-phase friction multiplier, and the multiplier was compared with the analytical value. Furthermore, the circular distributions of the pressure on the cylinders were measured. Based on the distribution and the fundamental theory of two-phase flow, the effects of the void fraction and mass flux per unit area on the pressure coefficient and the drag coefficient were evaluated. The drag coefficient was calculated by integrating the measured pressure on the tube by a numerical method. It was found that for low mass fluxes, the measured two-phase friction multipliers agree well with the analytical results, and good agreement for the effect of the void fraction on the drag coefficients, as calculated by the measured pressure distributions, is shown qualitatively, as compared to the existing experimental results.
Observation of Size Effect and Measurement of Mechanical Properties of Ti Thin Film by Bulge Test
Jung, Bong-Bu ; Lee, Hun-Kee ; Hwang, Kyung-Ho ; Park, Hyun-Chul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 19~25
DOI : 10.3795/KSME-B.2013.37.1.019
In this study, the mechanical properties of a Ti thin film are measured by a bulge test. In the bulge test, uniform pressure is applied to one side of the film. Measurement of the membrane deflection as a function of the applied pressure allows one to determine the mechanical properties of the film. Ti thin films with thicknesses of 1.0, 1.5, and
were deposited on a Si wafer by using an RF magnetron sputtering system. These specimens were annealed at
for 150, 300, and 600 s to investigate the effect of temperature on the yield stress and mechanical properties of the Ti films. The elastic modulus, residual stress, and yield stress of these membranes are measured by a bulge test. The experimental results suggest that the yield stress is sensitive to the film thickness and annealing time.
Investigation of Natural Convective Heat Flow Characteristics of Heat Sink
Jung, Tae Sung ; Kang, Hwan Kook ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 27~33
DOI : 10.3795/KSME-B.2013.37.1.027
To ensure proper functioning of electrical and mechanical systems, cooling devices are of great importance. A heat sink is the most common cooling device used in many industries such as the semiconductor, electronic instrument, LED lighting, and automotive industries. To design an optimal heat sink, the required surface area for heat radiation should be calculated based on an accurate expectation of the heat flow rate in the target environment. In this study, the convective heat flow characteristics were numerically investigated for a vertically installed typical heat sink and a horizontally installed one in free convection using ANSYS CFX. Comparative experiments were carried out to reveal the quantitative effect of the installation direction on the cooling performance. Moreover, the result was analyzed using the dimensionless correlation with the Nusselt number and Rayleigh number and compared with well-known theories. Finally, it was observed that the cooling performance of the vertically installed heat sink is approximately 10~15% better than that of the one in natural convection.
Investigation of Cooling Performance of Injection Molds Using Pulsed Mold Temperature Control
Sohn, Dong Hwi ; Park, Keun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 35~41
DOI : 10.3795/KSME-B.2013.37.1.035
In injection molding, the mold temperature is one of most important process parameters that affect the flow characteristics and part deformation. The mold temperature usually varies periodically owing to the effects of the hot polymer melt and the cold coolant as the molding cycle repeats. In this study, a pulsed mold temperature control was proposed to improve the part quality as well as the productivity by alternatively circulating hot water and cold water before and after the molding stage, respectively. Transient thermal-fluid coupled analyses were performed to investigate the heat transfer characteristics of the proposed pulsed mold heating and cooling system. The simulation results were then compared with those of the conventional mold cooling system in terms of the heating and cooling efficiencies of the proposed pulsed mold temperature control system.
Performance Investigation of Solar-Heating Ocean Thermal Energy Conversion (SH-OTEC) in Korea
Nguyen, Van Hap ; Lee, Geun Sik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 43~49
DOI : 10.3795/KSME-B.2013.37.1.043
The use of ocean thermal energy conversion (OTEC) to generate electricity is one of the methods proposed to utilize renewable energy and to protect the environment. In this study, simulations were performed to investigate the effect of weather conditions in the Ulsan region, Korea, on the efficiency of a solar-heating OTEC (SH-OTEC) system. This system utilizes solar thermal energy as the secondary heat source. Various working fluids were also simulated to select one that is suitable for this system. The results showed that R152A, R600, and R600A, in that order, were the most suitable working fluids. The effective area of the solar collector for a
increase in the collector outlet temperature fluctuated from 50 to
owing to the change in the monthly average solar gain. The annual average efficiency of the SH-OTEC increases to 6.23%, compared to that of a typical conventional OTEC, which is 2-4%.
Study on Lean-Premixed Combustion Characteristics of Dual-Stage Burner
Jang, Jae Hwan ; Cho, Ju Hyeong ; Kim, Han Seok ; Lee, Sang Min ; Kim, Min Kuk ; Ahn, Kook Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 51~57
DOI : 10.3795/KSME-B.2013.37.1.051
This study aims to experimentally investigate the combustion characteristics of a lean premixed swirl-stabilized burner with dual-stage fuel injection arrays. The results show that a variation in the fuel distribution to fuel stages 1 (upstream) and 2 (downstream) produces a noticeable change in the NOx and CO emissions. Reducing the confined ratio, defined as the ratio of the nozzle exit diameter to the liner diameter, may reduce NOx and CO emissions owing to reduced combustion loading and longer residence time, respectively. A nozzle exit velocity of 30 m/s shows the optimum characteristics in terms of NOx and CO emissions and flame stability: increasing or decreasing the nozzle exit velocity leads to a degradation in emissions or flame stability, respectively.
Experimental Study on Effects of Compressor for Automotive Air Conditioning System on Fuel Economy
Yoo, Seong-Yeon ; Kim, Young-Shin ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 59~65
DOI : 10.3795/KSME-B.2013.37.1.059
In this study, the effects of the compressor for the air conditioning system on the fuel economy were experimentally investigated in an actual automobile. This study aims to analyze the level of contribution of the driving torque of the compressor to the fuel economy. A torque sensor, which is directly set on the clutch of the compressor, is developed to obtain data about the compressor load, which influences the fuel efficiency, and then, the reliability of the torque sensor is verified by comparing the results with those of a torque meter in a bench test. An actual automobile equipped with the compressor and torque sensor is operated in a climate wind tunnel in which appropriate facilities are set up to evaluate the fuel efficiency. The compressor driving torque resulting from the difference in the compressor displacement is found to influence the fuel economy, and the fuel economy is found to be worsened by up to 2~3% with an around 11% increase in the compressor displacement under the same conditions.
Combustion and Spray Characteristics of Jet in Crossflow in High-Velocity and High-Temperature Crossflow Conditions
Yoon, Hyun Jin ; Ku, Kun Woo ; Kim, Jun Hee ; Hong, Jung Goo ; Park, Cheol Woo ; Lee, Choong Won ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 67~74
DOI : 10.3795/KSME-B.2013.37.1.067
A jet in a crossflow (JICF) has been extensively studied because of its wide applications in technological systems, including fuel injection into a ram-combustor. However, in the case of insufficient mixing performance of the liquid jet into the crossflow, the flame in a ram-combustor is unstable. In this study, the nonuniform flame and combustion instabilities due to lack of mixing performance were experimentally investigated. By performing correlations to predict the penetration height and break-up point, the spray and mixing characteristics of JICF have been studied. In particular, the improved correlations of penetration height are proposed in two distinctive domains depending on the X/d location of the crossflow.
Numerical Simulation of Heat Transfer in Chip-in-Board Package
Park, Joon Hyoung ; Shim, Hee Soo ; Kim, Sun Kyoung ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 75~79
DOI : 10.3795/KSME-B.2013.37.1.075
Demands for semiconductor devices are dramatically increasing, and advancements in fabrication technology are allowing a step-up in the number of devices per unit area. As a result, semiconductor devices require higher heat dissipation, and thus, cooling solutions have become important for guaranteeing their operational reliability. In particular, in chip-in-board packages, in which chips and passives are embedded in the substrates for efficient device layout, heat dissipation is of greater importance. In this study, a thermal model for layers of different materials has been proposed, and then, the heat transfer has been simulated by imposing a set of appropriate boundary conditions. Heat generation can be predicted based on the results, which will be utilized as practical data for actual package design.
Performance and Availability of Seawater Distiller with Heat Pipe Utilizing Low-Grade Waste Heat
Park, Chang-Dae ; Chung, Kyung-Yul ; Tanaka, Hiroshi ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 81~86
DOI : 10.3795/KSME-B.2013.37.1.081
Exhaust gas from a small portable electric generator is simply exhausted to the surroundings because the capacity and quality of the waste heat of this gas is generally not sufficient to recover and utilize. We have proposed a seawater distiller utilizing the thermal energy of waste gas from an electric generator. The distiller recovers heat from the waste gas by means of a heat pipe and uses it effectively through a multiple-effect diffusion-type structure. We constructed an experimental apparatus with a vertical single-effect still having a 4-stroke 50 cc generator engine and found that the experimental results for distillate productivity show good agreement with the theoretical predictions. The results show that the distiller can recover 52 W of waste heat from the gas at
, and ~85% of the recovered heat can be utilized for distillation to produce 70 g/h of fresh water. This is equivalent to a productivity of 500 g/h in the case of a 10-effect still. Therefore, the proposed distiller should be useful in remote areas where electricity and water grids are inadequate.
Development of Temperature Sensor Calibration System Using Cryocooler
Kim, Myung Su ; Choi, Yeon Suk ; Kim, Dong Lak ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 87~93
DOI : 10.3795/KSME-B.2013.37.1.087
The selection of the temperature sensor in a cryogenic system depends on the temperature range, shape, and accuracy. An accurate temperature sensor is essential for improving the reliability of an experiment. We have developed a calibration system for cryogenic temperature sensors using a two-stage cryocooler. To reduce the heat load, a thermal shield is installed at the first stage with multiple layer insulation (MLI). We have also developed a sensor holder for calibrating more than 20 sensors simultaneously in order to save time and reduce costs. This system can calibrate sensors at variable temperatures via temperature control using a heater. In this paper, we present the design and fabrication of the temperature sensor calibration system and a representative experimental result.
Measurement of Radiative Heat Flux Using Plate Thermometer
Park, Won-Hee ; Yoon, Kyung-Beom ;
Transactions of the Korean Society of Mechanical Engineers B, volume 37, issue 1, 2013, Pages 95~98
DOI : 10.3795/KSME-B.2013.37.1.095
Plate thermometers are used for measuring the radiative heat flux in high-temperature surroundings. The heat flux is calculated from the temperature measured at the back surface of the stainless steel surface of the meter. Heat fluxes from a Schmidt-Boelter gauge are measured as reference heat fluxes. A combined conductive coefficient is introduced to consider the heat loss to insulation, conduction through the stainless plate depth, and conduction from the non-uniform temperature of the plate of the plate thermometer. This coefficient is obtained using the repulsive particle swarm optimization.