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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 31, Issue 12 - Dec 2007
Volume 31, Issue 11 - Nov 2007
Volume 31, Issue 10 - Oct 2007
Volume 31, Issue 9 - Sep 2007
Volume 31, Issue 8 - Aug 2007
Volume 31, Issue 7 - Jul 2007
Volume 31, Issue 6 - Jun 2007
Volume 31, Issue 5 - May 2007
Volume 31, Issue 4 - Apr 2007
Volume 31, Issue 3 - Mar 2007
Volume 31, Issue 2 - Feb 2007
Volume 31, Issue 1 - Jan 2007
Selecting the target year
Characteristic Studies on Loop Heat Pipe with Micro Ceramic Wick
Park, Jong-Chan ; Lee, Chung-Gu ; Rhi, Seok-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 823~831
DOI : 10.3795/KSME-B.2007.31.10.823
This paper presents the experimental and simulation study of a loop heat pipe (LHP) that can be applied to present electronics, space missions and thermal control systems. The present experimental study was carried out employing sintered alumina ceramic wick (
). High purity R-134a, R-22 and water were also used as alternative working fluids in addition to ammonia. The experimental study showed that the maximum heat transfer performance for the test LHP in the vertical top heating mode was over 100 Watts when ammonia was used as the working fluid. The simulation results have been compared with the experimental results to validate a simulation model based on the thermal resistance network that was developed to evaluate the performance of LHPs, focusing on their prospective applications in electronics. The simulation model is based on the loop overall energy, mass, and momentum balance. The simulation program can predict the effects of various parameters which affect the performance of LHP within 5% compared with the experimental results.
Effects of a Flow Guide on the Arcing History in a Thermal Puffer Plasma Chamber
Lee, Jong-Chul ; Kim, Youn-Jea ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 832~839
DOI : 10.3795/KSME-B.2007.31.10.832
The geometry and dimensions of an expansion chamber are decisive factors in thermal puffer plasma chamber designs. Because they together dominate the temperature and speed at which the cooling gas from the chamber flows back through a flow channel to the arcing zone for the successful interruption of fault currents. In this study, we calculated the flow and mass transfer driven by arc plasma, and investigated the effects of a flow guide installed inside a thermal puffer plasma chamber. It is found that the existing cold gas of the chamber mixes with hot gases entrained from the arcing zone and is subjected to compression due to pressure build-up in the chamber. The pressure build-up with the flow guide is larger than that without due to a vortex which rotates clockwise around the chamber center. By the reverse pressure gradient, the mixing gas of the chamber flows back out for cooling down the residual plasma near current zero. In the case with the flow guide, the temperature just before current zero is lower than that without, and the Cu concentration with high electrical conductivity is also less than that without the flow guide.
Control Strategy and Characteristic Analysis of PEMFC/Photovoltaics Hybrid Vehicle
Ahn, Hyo-Jung ; Ji, Hyun-Jin ; Bae, Joong-Myeon ; Cha, Suk-Won ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 840~847
DOI : 10.3795/KSME-B.2007.31.10.840
This Paper focuses on modeling and simulation to analyze the characteristic of hybrid vehicle. The system includes a proton exchange membrane fuel cell(PEMFC), photovoltaic generator(PV), lead-acid battery, motor, vehicle and controller. Main electricity is produced by the PEMFC and battery to meet the requirements of a user load. When vehicle is parked in a sunny place, extra power is generated by the photovotaics and is charged in a battery for next drive. Further we evaluate usefulness of this hybrid vehicle by using ADVISOR - the advanced vehicle simulator written in the Matlab/Simulink environment. According to simulation results, the extra power obtained by photovoltaics which have been explored in nature conditions can help to reduce the electrical load of PEMFC and increase the efficiency (over 21 %).
Characteristics of Multiplexed Grooved Nozzles for High Flow Rate Electrospray
Kim, Kyoung-Tae ; Kim, Woo-Jin ; Kim, Sang-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 848~854
DOI : 10.3795/KSME-B.2007.31.10.848
The electrospray operated in the cone-jet mode can generate highly charged micro droplets in an almost uniform size at low flow rates. Therefore, the multiplexing system which can retain the characteristics of the cone-jet mode is inevitable for the electrospray application. This experiment reports the multiplexed grooved nozzle system with the extractor. The effects of the grooves and the extractor on the performance of the electrospray were evaluated through experiments. Using the grooved nozzle, the stable cone-jet mode can be achieved at the each groove in the grooved mode. Furthermore, the number of nozzles per unit area is increased by the extractor. The multiplexing density is 12 jets per
at 30 mm distance from the nozzle tip to the ground plate. The multiplexing system for the high flow rate electrospray is realized with the extractor which can diminish the space charge effect without sacrificing characteristics of the cone-jet mode.
Investigation of the Water Gas Shift from Reforming Gas for CO Removal
Kim, Seong-Cheon ; Youn, Moon-Jung ; Chun, Young-Nam ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 855~859
DOI : 10.3795/KSME-B.2007.31.10.855
Hydrogen as an energy carrier in fuel cell offers perhaps the largest potential benefits of reduced emissions of pollutants and greenhouse gases. The generation of high-purity hydrogen from hydrocarbon fuels is essential for efficient operation of fuel cell. Reduction of carbon monoxide to an acceptable level of 10ppm involves high temperature and low temperature water gas shift (WGS), followed by selective oxidation of residual carbon monoxide. The WGS reactor was designed and tested in this study to produce hydrogen-rich gas with CO to less than 5000 ppm. In the water gas shift operation, gas emerges from the reformer is taken through a high temperature shift (HTS) catalyst to reduce the CO concentration to about
followed to about 5000 ppm via a low temperature shift (LTS) catalyst.
Drying Performance Simulation for the Basic Design of a Heat Pump Dryer
Lee, Kong-Roon ; Kim, Ook-Joong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 860~867
DOI : 10.3795/KSME-B.2007.31.10.860
Heat pump drying has a great potential for energy saving due to its high energy efficiency in comparison with conventional air drying. In the present study, the performance simulation for the basic design of a heat pump dryer has been carried out. The simulation includes one-stage heat pump cycle, simple drying process using the drying efficiency. As an example, the heat pump cycle with Refrigerant 134a has been investigated. For the operating conditions such as the average temperature of the condenser, the heat rate released in the condenser, the flow rate of drying air, and drying efficiency, the simulation has been carried out to figure out the performance of the dryer. The parameters considered in the design of the dryer are COP, MER, SMER, the rate of dehumidification, the temperature and humidity of drying air and those parameters are compared for different conditions after carrying out the simulation.
Performance Evaluations of a Residential Small Multi-Refrigeration System Considering the Adiabatic Characteristics
Lee, Moo-Yeon ; Lee, Dong-Yeon ; Joo, Young-Ju ; Kim, Sang-Uk ; Kim, Yong-Chan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 868~875
DOI : 10.3795/KSME-B.2007.31.10.868
In this paper, performance characteristics of a domestic kim-chi refrigerator are predicted by using the theoretical calculation and experimental method. The objective of this study is to find out the best design points of the refrigeration system and to calculate an adiabatic characteristic with variation to outdoor temperatures. The best design points such as refrigerant charge amount and capillary length were experimentally investigated. And the theoretical calculation is conducted as a function of calculation parameters and outdoor temperatures. According to this study results, the best design points of a refrigeration system with 2 rooms are 95 g of a refrigerant charge amount and 3500 / 3500 mm of capillary lengths and the best design points of a refrigeration system with 3 rooms are 100 g of a refrigerant charge amount and 3000/3000/6000mm of capillary lengths. And the power consumptions of both systems are 13.57 and 18.2 kWh/month. The worst part of heat loss is a front side of a domestic kim-chi refrigerator body.
Numerical Analysis on the Design of a Thermal Mass Air Flow Sensor with Various Heating Modes
Jeon, Hong-Kyu ; Lee, Joon-Sik ; Park, Byung-Kyu ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 876~883
DOI : 10.3795/KSME-B.2007.31.10.876
Numerical simulations are conducted for the design of a micro thermal mass air flow sensor (MAFS), which consists of a microfabricated heater and thermopiles on the silicon-nitride (
) thin membrane structure. It is important to find the proper locations of these thermal elements in the design of MAFS with improved sensitivity. Three heating modes of the micro-heater are considered: constant temperature, constant power and heating pulses. The analyses are focused on the membrane temperature profile near the sensing section. Considered are the practical flow velocities, ranging from 3 m/s to 35 m/s, and the corresponding Reynolds numbers from 1000 to 10000. The results show that one of optimum sensing locations is about
away from the microheater. It is concluded that the heating mode and configurations of thermal elements are the main factors for the MAFS with higher sensitivity.
Experimental Study for Performance Evaluation of Gate Valve
Cho, Tack-Dong ; Yang, Sang-Min ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 884~888
DOI : 10.3795/KSME-B.2007.31.10.884
It is necessary to evaluate periodically the performance of the AOV(air-operated valve) which is used for controlling flow and pressure in nuclear power plant. The required thrust for actuating valve and available thrust of actuator are calculated with conditions of flow through a valve in this study and operating performance is analyzed through comparing two thrusts. In general, differential pressure is increased according to increase the flow rate and differential pressure affects the required thrust of valve. We found the fact that it is possible not to close the valve perfectly because required thrust becomes bigger than available thrust of actuator.
Experimental Study of Axial Slit Wall Effect on Taylor-Couette Flow
Lee, Sang-Hyuk ; Kim, Hyoung-Bum ;
Transactions of the Korean Society of Mechanical Engineers B, volume 31, issue 10, 2007, Pages 889~894
DOI : 10.3795/KSME-B.2007.31.10.889
The effect of the axial slit of outer cylinder on Taylor-Couette flow was experimentally investigated. The radius ratio and aspect ratio of the model was 0.825 and 48, respectively. The depth of slits was 5mm and total 18 slits were azimuthally located along the inner wall of outer cylinder. We used PIV method to measure the flow field and applied refractive index matching method to resolve the image distortion due to the complex model geometry. The results showed the axial slit did not affect the transition from laminar Couette flow to Taylor vortex. The effect of slit wall appeared when the Reynolds number is larger than Re=143 and the slit model shows the transition to turbulent Taylor vortex flow above Re=143.