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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 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
Selecting the target year
Technology for Real-Time Identification of Steady State of Heat-Pump System to Develop Fault Detection and Diagnosis System
Kim, Min-Sung ; Yoon, Seok-Ho ; Kim, Min-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 333~339
DOI : 10.3795/KSME-B.2010.34.4.333
Identification of a steady state is the first step in developing a fault detection and diagnosis (FDD) system of a heat pump. In a complete FDD system, the steady-state detector will be included as a module in a self-learning algorithm, which enables the working system's reference model to "tune" itself to its particular installation. In this study, a steady-state detector of a residential air conditioner based on moving windows was designed. Seven representative measurements were selected as key features for steady-state detection. The optimized moving-window size and the feature thresholds were decided on the basis of a startup-transient test and no-fault steady-state test. Performance of the steady-state detector was verified during an indoor load-change test. In this study, a general methodology for designing a moving-window steady-state detector for applications involving vapor compression has been established.
Parametric Study of SOFC System Efficiency Under Operation Conditions of Butane Reformer
Kim, Sun-Young ; Baek, Seung-Whan ; Bae, Gyu-Jong ; Bae, Joong-Myeon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 341~347
DOI : 10.3795/KSME-B.2010.34.4.341
In this study, the efficiency of a solid-oxide fuel cell (SOFC) system with a steam reformer or prereformer was analyzed under various conditions. The main components of the system are the reformer, SOFC, and water boiling heat recovery system. Endothermic and exothermic reactions occur in the reformer and SOFC, respectively. Hence, the thermal management of the SOFC system greatly influences the SOFC system efficiency. First, the efficiencies of SOFC systems with a steam reformer and a prereformer are compared. The system with the prereformer was more efficient than the one with steam reformer due to less heat loss. Second, the system efficiencies under various prereformer operating conditions were analyzed. The system efficiency was a function of the heat requirement of the system. The efficiency increased with an increase in the operating temperature of the prereformer, and the maximum system efficiency was observed at
for a S/C of 2.0.
Numerical Analysis-Based Design of PEMFC Channel, Fabrication of Channels, and Performance Test Using SU-8
Choi, In-Jea ; Wang, Hak-Min ; Choi, Kap-Seung ; Kim, Hyung-Man ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 349~354
DOI : 10.3795/KSME-B.2010.34.4.349
Fuel cells have attracted enormous interest as new power sources because the cells can be used to solve the problem of environmental pollution as well as the natural-resource exhaustion problem. In this study, hydrogen-gas flow in microchannels of different shapes was numerically analyzed to improve the efficiency of a microfuel cell. Flow characteristics in six microchannels of different shapes but under identical boundary conditions were simulated. The analysis result shows that the flow characteristics such as velocity, uniformity, and flow rate, greatly depend upon the channel shape. This implies that the efficiency of microfuel cell can be expected to be increased by adopting the optimal configuration of channel shape for hydrogen-gas flow. The experimental results show that power density of a PEMFC with a microflow channel is higher than that of a PEMFC without a microflow channel; however, a durable catalyst is required in MEA.
Responses of Artificial Flow-Sensitive Hair for Raider Detection via Bio-Inspiration
Park, Byung-Kyu ; Lee, Joon-Sik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 355~364
DOI : 10.3795/KSME-B.2010.34.4.355
Filiform hairs that respond to movements of the surrounding medium are the mechanoreceptors commonly found in arthropods and vertebrates. In these creatures, the filiform hairs function as a sensory system for raider detection. Parametric analyses of the motion response of filiform hairs are conducted by using a mathematical model of an artificial flow sensor to understand the possible operating ranges of a microfabricated device. It is found that the length and diameter of the sensory hair are the major parameters that determine the mechanical sensitivities and responses in a mean flow with an oscillating component. By changing the hair length, the angular displacement, velocity, and acceleration could be detected in a wide range of frequencies. Although the torques due to drag and virtual mass are very small, they are also very influential factors on the hair motion. The resonance frequency of the hair decreases as the length and diameter of the hair increase.
A Chemical Reactor Modeling for Prediction of NO Formation of Methane-Air Lean Premixed Combustion in Jet Stirred Reactor
Lee, Bo-Rahm ; Park, Jung-Kyu ; Lee, Do-Yong ; Lee, Min-Chul ; Park, Won-Shik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 365~373
DOI : 10.3795/KSME-B.2010.34.4.365
A chemical reactor model (CRM) was developed for a jet stirred reactor (JSR) to predict the emission of exhaust such as NOx. In this study, a two-PSR model was chosen as the chemical reactor model for the JSR. The predictions of NO formation in lean premixed methane-air combustion in the JSR were carried out by using CHEMKIN and GRI 3.0 methane-air combustion mechanism which include the four NO formation mechanisms. The calculated results were compared with Rutar's experimental data for the validation of the model. The effects of important parameters on NO formation and the contributions of the four NO pathways were investigated. In the flame region, the major pathway is the prompt mechanism, and in the post flame region, the major pathway is the Zelodovich mechanism. Under the lean premixed condition, the N2O mechanism is the important pathway in both flame and postflame regions.
Experimental Study of Steam Reforming Assisted by Catalytic Combustion in Concentric Annular Reactor
Ghang, Tae-Gyu ; Yu, Sang-Seok ; Kim, Yong-Mo ; Ahn, Kook-Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 375~381
DOI : 10.3795/KSME-B.2010.34.4.375
In this paper, the heat-transfer characteristics of steam reforming in an annular reactor are presented. Heat is supplied by the catalytic combustion of syn-gas. The thermal behaviors of exothermic and endothermic reactions in a directly coupled concentric-tube packed-bed reactor were investigated experimentally. The gas mixture supplied for catalytic combustion consisted of the off-gas emitted from MCFC anode. Methane in steam at a suitable S/C (steam-to-carbon) ratio was used in the reforming reactions. On the basis of the experimental results, a simple simulation was performed to predict the temperature profile required in the reforming side of the reactor to achieve optimum hydrogen yield. The results of this study may be utilized as reference data in future studies for further development of coupled reactors.
Experimental Study of Power Generation Performance of Small-Scale Thermoelectric System
Chung, Jae-Hoon ; Kim, Woo-Chul ; Lee, Jin-Ho ; Yu, Tae-U ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 383~390
DOI : 10.3795/KSME-B.2010.34.4.383
In this study, a thermoelectric power generation system was constructed for a waste-heat recovery. Thermoelectric modules were attached to a stainless steel duct, and a hot air blower was set such that it faced the duct inlet. We found that to achieve the maximum power out of the system, the temperature in the hot side of the thermoelectric module should be uniform. The optimum compressive pressure exerted on the module was observed. Further, the thermoelectric power performance was evaluated using the heat sink attached to the cold side of the thermoelectric module. In particular, when using a natural-convection heat sink, the power output difference is approximately five times.
Cryogenic Performance Test of LOX Turbopump in Liquid Nitrogen
Kim, Jin-Sun ; Hong, Soon-Sam ; Kim, Dae-Jin ; Choi, Chang-Ho ; Kim, Jin-Han ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 391~397
DOI : 10.3795/KSME-B.2010.34.4.391
Performance tests of a liquid-oxygen pump were carried out using liquid nitrogen (LN2) as a working fluid in a cryogenic turbopump test facility in Korea Aerospace Research Institute (KARI). The tests were performed at 30-55% of the design rotational speed, and the results were compared with those from a water test. The experimental results confirmed the similarity of the hydraulic performance, which allows the prediction of the pump performance at a design rotational speed of 20,000 rpm. The overall cavitation performance of the pump in the cryogenic environment was better than that in the water environment for all ranges of flow rates and rotational speeds. Critical cavitation number at the design flow rate was determined as 0.012 from the cryogenic test, and as 0.024 from the water test. The improved cavitation performance is due to the thermodynamic effect in cryogenic fluids.
Study of Characteristics of Self-Excitation in Lifted Laminar Free-Jet Propane Flames Diluted with Nitrogen
Yoon, Sung-Hwan ; Park, Jeong ; Kwon, Oh-Boong ; Bae, Dae-Seok ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 399~408
DOI : 10.3795/KSME-B.2010.34.4.399
The characteristics of lifted laminar propane flames diluted with nitrogen have been investigated experimentally to elucidate self-excitation and the effects of flame curvature. Flame oscillation modes are classified as follows: oscillation induced by heat loss, a combination of oscillations induced by heat loss and buoyancy, and a combination of the oscillations induced by heat loss and diffusive thermal instability. It is shown that the oscillation induced only by heat loss is not relevant to the diffusive thermal instability and hydrodynamic instability caused by buoyancy; this oscillation is observed under all lift-off flame conditions irrespective of the fuel Lewis number. These experimental evidences are displayed through the analysis of the power spectrum for the temporal variation of lift-off height. The possible mechanism of the oscillation induced by heat loss is also discussed.
Experimental Study of Effect of CO
Addition on Oxy-Fuel Combustion in Triple Concentric Multi-Jet Burner
Kim, Seung-Hwan ; Park, Jang-Hee ; Lee, Dae-Keun ; Shin, Hyun-Dong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 409~416
DOI : 10.3795/KSME-B.2010.34.4.409
The use of oxy-fuel combustion and flue gas recirculation (FGR) for
reduction has been studied by many researchers. This study focused on the characteristics of oxy-fuel combustion and the effects of
addition from the point of view of oxygen feeding ratio (OFR) and the position of
addition in order to reproduce an FGR system with a triple concentric multi-jet burner. Oxy-fuel combustion was stable at all OFRs at a fuel flow-rate of 15 lpm, which corresponds to an equivalence ratio of 0.93; however, the structure and length of the flame varied at different OFRs. When
was added in oxy-fuel combustion, various stability modes such as stable, transient, quasistable, unstable, and blow-out were observed. The temperature in the combustion chamber decreased upon
addition in all conditions, and the maximum reduction in temperature was below 1800 K.
concentration with respect to height varied with the volume percent of
at the nozzle tip.
Hydrocarbon Speciation in Low Temperature Diesel Combustion
Han, Man-Bae ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 417~422
DOI : 10.3795/KSME-B.2010.34.4.417
Low temperature diesel combustion was achieved via a combination of late injection timing (
CA BTDC to
CA BTDC) and heavy exhaust gas recirculation (37% to 48%) with ultra low sulfur Swedish diesel fuel in a 1.7L common rail direct injection diesel engine. When injection timing is retarded at a certain exhaust gas recirculation rate, the particulate matter and nitrogen oxides decease simultaneously, while the hydrocarbon and carbon monoxide increase. Hydrocarbon speciation by gas chromatography using a flame ionization detector reveals that the ratio of partially burned hydrocarbon, i.e., mainly alkenes increase as the injection timing is retarded and exhaust gas recirculation is increased. The two most abundant hydrocarbon species are ethene which is a representative species of partially burned hydrocarbons, and n-undecane, which is a representative species of unburned hydrocarbons. They may be used as surrogate hydrocarbon species for performing a bench flow reactor test for catalyst development.
Evaluation of Fine-Particle Removal Performance of Novel ESP with Highly Durable Chargers and Collectors
Kim, Hak-Joon ; Han, Bang-Woo ; Hong, Won-Seok ; Shin, Wan-Ho ; Song, Dong-Keun ; Jung, Sang-Hyeon ; Kim, Yong-Jin ; Oh, Won-Suk ; Hwang, Kyu-Dong ; Yoo, Seong-Yeon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 423~428
DOI : 10.3795/KSME-B.2010.34.4.423
Electrostatic precipitators (ESPs) used currently in industries for removing fine particles from semiconductors have to be made of expensive anticorrosive metallic materials in order to maintain their particle-removal performance. To satisfy the economical demands of industries, a novel ESP was developed; in this ESP, the charger is made of carbon fibers and collection plates consist of PET films among which an aluminum sheet is inserted. The ESP was evaluated by changing the voltages applied to the chargers and collection plates, flow rates, and number of charging channels. KCl particles with mean diameters of 100 nm were used, and a scanning mobility particle sizer was used to measure the changes in particle number concentrations upstream and downstream of the ESP. The experimental results showed that more than 90% of the particles were removed by using the ESP containing ionizers with nine channels and 65-mm collection plates at
when voltages of 7 kV and 10 kV were applied to the ionizers and collection plates, respectively.
Technology Based on Wall-Thinning Prediction and Numerical Analysis Techniques for Wall-Thinning Analysis of Small-Bore Carbon Steel Piping
Lee, Dae-Young ; Hwang, Kyeong-Mo ; Jin, Tae-Eun ; Park, Won ; Oh, Dong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 429~435
DOI : 10.3795/KSME-B.2010.34.4.429
In approximately fifty utilities, including KHNP (Korea Hydro & Nuclear Power), CHECWORKS is used as a tool for predicting and managing the wall thinning of carbon steel piping; this wall thinning is caused by flow-accelerated corrosion (FAC). It is known that CHECWORKS is only applicable to predict the wall thinning of piping with large bores. When dealing with small-bore steel piping, FAC engineers measure the thickness of the susceptible area that is selected on the basis of the experience and judgment of the engineer. This paper proposes the application of CHECWORKS for the management of wall thinning of small-bore piping. Four small-bore pipelines of a domestic nuclear power plant were analyzed from the viewpoints of FAC and fluid dynamics by using CHECWORKS and FLUENT code. Depending on the engineer's skill, CHECWORKS can also be used for the management of wall thinning of small-bore piping.
Supplementation of Flow Accelerated Corrosion Prediction Program Using Numerical Analysis Technique
Hwang, Kyeong-Mo ; Jin, Tae-Eun ; Park, Won ; Oh, Dong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 437~442
DOI : 10.3795/KSME-B.2010.34.4.437
Flow-accelerated corrosion (FAC) leads to thinning of steel pipe walls that are exposed to flowing water or wet steam. From experience, it is seen that FAC damage to piping at fossil and nuclear plants can result in outages that require expensive repairs and can affect plant reliability and safety. CHECWORKS have been utilized in domestic nuclear plants as a predictive tool to assist FAC engineers in planning inspections and evaluating the inspection data so that piping failures caused by FAC can be prevented. However, CHECWORKS may be occasionally ignore local susceptible portions when predicting FAC damage in a group of pipelines after constructing a database for all the secondary side piping in nuclear plants. This paper describes the methodologies that can complement CHECWORKS and the verifications of CHECWORKS prediction results using numerical analysis. FAC susceptible locations determined using CHECWORKS for two pipeline groups of a nuclear plant was compared with determined using the numerical-analysis-based FLUENT.
Effect of Propellant-Supply Pressure on Liquid Rocket Engine Performance
Cho, Won-Kook ; Park, Soon-Young ; Nam, Chang-Ho ; Kim, Chul-Woong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 34, issue 4, 2010, Pages 443~448
DOI : 10.3795/KSME-B.2010.34.4.443
In this paper, the changes in performance parameters, e.g., the combustor pressure, turbine power, engine mixture ratio, temperature of gas generator, and product gas, of a liquid rocket engine employing gas generator cycle with the variations in propellant-supply pressure have been described. Engine performance is numerically calculated using the 13 major system-level variables of the rocket engine. The combustor pressure and turbine power increase with an increase in the oxidizer-supply pressure and decrease with an increase in fuel-supply pressure. The lower mixture ratio of gas generator for increased fuel mass flow rate decreases the gas generator gas temperature and deteriorates the gas material properties as the turbine working fluid. The turbine power decreases with an increase in fuel-supply pressure; this results in a decrease in the main-combustor pressure, which is directly proportional to engine thrust.