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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 29, Issue 12 - Dec 2005
Volume 29, Issue 11 - Nov 2005
Volume 29, Issue 10 - Oct 2005
Volume 29, Issue 9 - Sep 2005
Volume 29, Issue 8 - Aug 2005
Volume 29, Issue 7 - Jul 2005
Volume 29, Issue 6 - Jun 2005
Volume 29, Issue 5 - May 2005
Volume 29, Issue 4 - Apr 2005
Volume 29, Issue 3 - Mar 2005
Volume 29, Issue 2 - Feb 2005
Volume 29, Issue 1 - Jan 2005
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Wind Tunnel Test of Smart Un-manned Aerial Vehicle(SUAV) for TR-E2S1 Configuration
Yoon SunEiun ; Cho Tahwan ; Chung Jindeog ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 295~305
DOI : 10.3795/KSME-B.2005.29.3.295
To improve the aerodynamic effciency of TR-E2, a new configuration so called TR-E2Sl was introduced. TR-2251 is composed of different wing airfoil section and T-tail shape compared with TR-E2. Wind tunnel test for TR-EBS1 had been performed by changing the incidence angles of wing and deflection angles of control surfaces such as elevator and rudder. Also the on/off effect of ventral fin attached underneath of AFT fuselage was tested. Test result showed that variations of wing incidence angle did not cause any severe differences in aerodynamic characteristics. Longitudinal and directional characteristics of TR-E2S1 show stable for the pitch and yaw motions. However, the lateral stability of TR-E2S1 is not stable for a certain control surface deflection.
Performance Characteristics of Side Channel Type Regenerative Pumps
Kang Shin-Hyoung ; Lim Hyung-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 306~313
DOI : 10.3795/KSME-B.2005.29.3.306
The performance of a regenerative pump is affected by many parameters, especially blade shape of impeller, leakage flow in the clearance and head losses at the inlet & outlet. An impeller with J-shape blade was designed and 5 times scale up model was tested at similarity conditions to evaluate the performance. Performance variations with clearance change were executed. The amounts of leakage flow through the clearance were estimated using the one-dimensional leakage flow models and analysis. Main leakage flow is generated through the gap between the impeller and casing. The inlet & outlet head losses were also estimated. Such corrections are very important to evaluate the final performance of the impeller and pump. Cavitation test was also performed at 1,200 rpm. NPSH of the regenerative pump was obtained and growth of cavity within blades was visualized.
A Study of 3-Dimensional Turbulent Channel Flow Using Discrete Wavelet Transform
Kim Kangshik ; Lee Sanghwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 314~321
DOI : 10.3795/KSME-B.2005.29.3.314
Discrete Wavelet Transform (DWT) has been applied to the Direct Numerical Simulation (DNS) data of turbulent channel flow. DWT splits the turbulent flow into two orthogonal parts, one corresponding to coherent structures and the other to incoherent background flow. The coherent structure is extracted from not vorticity field but velocity`s since the channel flow is not isoropic. By comparing DWT`s result of channel flow with that of isotropic flow, it is shown that coherent structure maintains the properties of original channel flow. The velocity field of coherent structures can be represented by few wavelet modes and that these modes are sufficient to reproduce the velocity probability density function (PDF) and the energy spectrum over the entire inertial range. The remaining incoherent background flow is homogeneous, has small amplitude, and is uncorrelated. These results are compared with those obtained for the same compression rate using large eddy simulation (LES) filtering. In contrast to the incoherent background flow of DWT, the LES subgrid scales have a much larger amplitude and are correlated, which makes their statistical modeling more difficult.
Flow Characteristics of Wake Flow with Relation to a Tip Leakage Vortex at Different Flow Rates in an Axial Flow Fan
Kim Kwang-Yong ; Jang Choon-Man ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 322~329
DOI : 10.3795/KSME-B.2005.29.3.322
The flow characteristics in the blade passage and in the wake region of a low speed axial flow fan have been investigated by experimental analysis using a rotating hot-wire sensor for design and off-design operating conditions. The results show that the tip leakage vortex is moved upstream when flow rate is decreased, thus disturbing the formation of wake flow near the rotor tip. The tip leakage vortex interfaces with blade pressure surface, and results in high velocity fluctuation near the pressure surface. From axial velocity distributions downstream of the fan rotor, large axial velocity decay near the rotor tip is observed at near stall condition, which results in large blockage compared to that at the design condition. Although the wake flow downstream of the rotor blade is clearly measured at all operating conditions, the trough of the high velocity fluctuation due to Karmann vortex street in the wake flow is mainly observed at a higher flow condition than the design flow rate.
Behavior of an Impinging Droplet on a Solid Surface with a Variation of Liquid Temperature
Lee Dong Jo ; Park Byung Sung ; Chung Jin Taek ; Kim Ho Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 330~339
DOI : 10.3795/KSME-B.2005.29.3.330
An experimental study on the behavior of droplets impinging on a solid flat surface was carried out in the present study. Breakup of a liquid droplet impinging on a solid surface has been investigated experimentally for various liquids with different properties. The liquid droplet temperature and incident angle were chosen as major parameters. Liquid droplet temperature and incident angle varied in the range from
respectively. It was found that the variation of droplet temperature influences upon the mean diameter and uniformity of droplets which were bounced out from the solid surface. With increase of incident angle the dispersion mass fraction increases, causing the decrease of liquid film flow rate. As the liquid temperature increases, dispersion mass fraction increases since the surface tension decreases.
Effect of Number of Rough Walls on Pressure Drop and Heat Transfer in Square Channel
Bae Sung Taek ; Kim Myoung Ho ; Jin Yong Soo ; Kim Sung Tae ; Ahn Soo Wan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 340~348
DOI : 10.3795/KSME-B.2005.29.3.340
Repeated ribs are used on heat exchange surfaces to promote turbulence and enhance convective heat transfer. Applications include fuel rods of gas-cooled nuclear reactors, inside cavities of turbine blades, and internal surfaces pipes used in heat exchangers. Despite the great number of literature papers, only few experimental data concern detailed distributions of friction factors and heat transfer coefficients in square channels varying the number of rough walls. This issue is tackled by investigating effects of different number of ribbed walls on heat transfer and friction characteristics in square channel. The rough wall have a
inclined square rib. Uniform heat flux is maintained on whole inner heat transfer channel area. The heat transfer coefficient and friction factor values increase with increasing the number of rough walls.
Characteristics of Methane Non-Premixed Multiple Jet Flames
Kim Jin Hyun ; Lee Byeong-Jun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 349~355
DOI : 10.3795/KSME-B.2005.29.3.349
It has been reported that propane non-premixed interacting flames are not extinguished even in 210m/s if eight small nozzles are arranged along the imaginary circle of 40 ~ 72 times the diameter of single nozzle. In this research, experiments were extended to the methane flame. Nine nozzles were used- eight was evenly located along the perimeter of the imaginary circle and one at the geometric center. The space between nozzles, s, the exit velocity and the role of the jet from the center nozzle were considered. On the contrary to the propane non-premixed flame, small amount of fuel fed through the center nozzle makes the methane diffusion flame stable even at the choking conditions. In the laminar region, the flame at the center nozzle anchored the outer lifted flames.
The Spray Characteristics of Swirl and Slit Injector to DISI Engine Using LIEF and Mie-scattering Method
Lee Kihyung ; Hwang Kyumin ; Lee Changhee ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 356~367
DOI : 10.3795/KSME-B.2005.29.3.356
The spray characteristics of DISI injector have a great role in gasoline engine efficiency and emission. Thus, many researchers have studied to investigate the spray characteristics of swirl and slit injectors that are used in a DISI engine. In this study, we tried to provide spray parameters, which affect on the spray characteristics such as injection pressure, ambient pressure and ambient temperature. In addition, we calculated
to investigate the break up mechanism of test injectors and obtained
to evaluate the spray characteristics. As the ambient pressure increases in case of slit injector,
decreases. The laser-induced exciplex fluorescence (LIEF) technique, which is based on spectrally resolved two-color fluorescent emissions, has applied to measure the liquid and vapor phases for on evaporating spray simultaneously. The TMPD/naphthalene proposed by Melton is used as a dophant to detect exciplex signal. The temporal and spatial distribution of liquid and vapor phases during the mixture formation process was measured by this technique. In the LIEF technique, the vapor phase is detected by the monomer fluorescence while the liquid phase is tracked by the exciplex fluorescence. From this experiment, we found that the spray area of the vapor phase is increased with elapsed time after injection and the area of liquid is decreased when the ambient pressure is 0.1MPa. However, the area tends to increase until the end of injection when the ambient pressure is 1.0MPa.
A Transitional Behavior of a Premixed Flame and a Triple Flame in a Lifted Flame(I)
Jang Jun Young ; Park Jeong ; Kim Tae Kwon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 368~375
DOI : 10.3795/KSME-B.2005.29.3.368
We have presented characteristics of a transitional behavior from a premixed flame to a triple flame in a lifted flame according to the change of equivalence ratio. The experimental apparatus consisted of a slot burner and a contraction nozzle for a lifted flame. As concentration difference of the both side of slot burner increases, the shape of flame changed from a premixed flame to a triple flame, and the liftoff height decreased to the minimum value and then increased again. Around this minimum point, it is confirmed a transition regime from premixed flame to triple flame. Consequently, the experimental results of the liftoff height, flame curvature, and luminescence intensity showed that the stabilized laminar lifted flame regime is categorized by regimes of premixed flame, triple flame and critical flame.
A Transitional Behavior of a Premixed Flame and a Triple Flame in a Lifted Flame(II)
Jang Jun Young ; Kim Tae Kwon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 376~383
DOI : 10.3795/KSME-B.2005.29.3.376
In the paper we investigate characteristics of a transitional behavior from a premixed flame to a triple flame in a lifted flame according to the change of equivalence ratio. In previous study, we showed that the stabilized laminar lifted flame regime is categorized by regimes of premixed flame, triple flame and critical flame. A gas-chromatograph is used to measure concentration field, a smoke-wire system is used to measure streak line, and a PIV system is used to measure velocity field in lifted flame. In the visualization experiment of smoke wire, the flow divergence and redirection reappeared in premixed flame as well as triple flame. Thus we cannot express the flame front of lifted flame has a behavior of triple flame with only flow divergence and redirection. In PIV measurement, flow velocity for those three flames has minimum value at the tip of flame front. To differentiate triple flame and premixed flame,
value of partially premixed fraction is employed. The partially premixed fraction
was constant in premixed flame. In critical flame small gradient appears over the whole regime. In triple flame, typical diffusion flame shape is obtained as parabolic distribution type due to diffusion flame trailing.
Variation of Exhaust Gas Temperature with the Change of Spark Timing and Exhaust Valve Timing During Cold Start Operation of an SI Engine
Yang Chang-Seok ; Park Young-Joon ; Cho Yong-Seok ; Kim Duk-Sang ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 384~389
DOI : 10.3795/KSME-B.2005.29.3.384
Experimental study of variation of exhaust gas temperature was carried out with the changes of spark timing and exhaust valve timing during the cold start operation of an SI engine. To investigate the effects of these variables on combustion stability, cylinder pressure and exhaust gas temperature were measured and analyzed. Experimental results showed that exhaust gas temperature increased when spark and exhaust valve timings were retarded from the baseline cases. However, combustion stability during cold start deteriorated under the retarded conditions. To increase exhaust gas temperature for fast warmup of catalysts while maintaining combustion stability, an optimal condition for spark and valve timing retard should be appied for the cold start period.
An Experimental Study on the Extinction Limit Extension of Unsteady Counterflow Diffusion Flames
Lee Uen Do ; Lee Ki Ho ; Oh Kwang Chul ; Lee Eui Ju ; Shin Hyun Dong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 390~401
DOI : 10.3795/KSME-B.2005.29.3.390
In this study, extinction limit extension of unsteady
/air diffusion flames was investigated experimentally. A spatially locked flame in an opposing jet burner was perturbed by linear velocity variation, and time-dependent flame luminosity, transient maximum flame temperature and OH radical were measured over time with the high speed camera, Rayleigh scattering method and OH laser-induced fluorescence, respectively. Unsteady flames survive at strain rates that are much higher than the extinction limit of steady flames, and unsteady extinction limits extend as the slope of the strain rate increases or the initial strain rate decreases. We verified the validity of the equivalent strain rate concept by comparing the course of unsteady extinction process and steady extinction process, and it was found that the equivalent strain rate concept represents well the unsteady effect of a convective-diffusive zone. To investigate the reason of the unsteady extinction limit extension, we subtracted the time lag of the convective-diffusive zone by using the equivalent strain concept. Then the modified unsteady extinction limits become smaller than the original unsteady extinction limits, however, the modified unsteady extinction limits are still larger than the steady extinction limits. These results suggest that there exist the unsteady behavior of a diffusive-reactive zone near the extinction limit due to the chemical non-equilibrium states associated with unsteady flames.
A Study on the Temperature Behavior on Impinging Plate of Diesel Spray with Ultra High Pressure
Lee Jong Tai ; Jeong Dae Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 402~408
DOI : 10.3795/KSME-B.2005.29.3.402
The instantaneous temperature behaviors on impinging plate in case of ultra high pressure have been measured and analyzed by using the instantaneous temperature probe and ultra high pressure injection equipment. The temperature drop was largest at P1 which is center of impinging spray and decreased with propagation of spray to the radius direction. The temperature drop was bigger in case of higher temperature of impinging plate. The temperature drop decreased with increase of injection pressure. But decreasing rate of temperature drop was slight over 2,500 bars. Therefore, it was predicted that the fuel evaporation versus the increase of injection pressure was maximum at around 2,500 bars.
Web-Based On-Line Thermal Performance Analysis System for Turbine Cycle of Nuclear Power Plant
Choi KiSang ; Choi KwangHee ; Ji MoonHak ; Hong SeungYeol ; Kim SeongKun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 409~416
DOI : 10.3795/KSME-B.2005.29.3.409
We need to develop a on-line thermal performance analysis system for nuclear power plant to determine performance status and heat rate of turbine cycle. We have developed PERUPS(PERformance Upgrade System) to aid the effective performance analysis of turbine cycle. Procedures of performance calculation are improved using several adaptations from standard calculation algorithms based on PTC(Performance Test Code). Robustness in the on-line performance analysis is increased by verification & validation scheme for measured input data. The system also provides useful web interfaces for performance analysis such as graphic heat balance of turbine cycle and components, turbine expansion lines, automatic generation of analysis report. The system was successfully applied for YongGwang nuclear plant unit
Influence of Propane and Butane on Engine Performance in a Homogeneous Charge Compression Ignition(HCCI) Engine
Choi Gyeung Ho ; Kim Ji Moon ; Han Sung Bin ;
Transactions of the Korean Society of Mechanical Engineers B, volume 29, issue 3, 2005, Pages 417~423
DOI : 10.3795/KSME-B.2005.29.3.417
This paper describes the engine performance of a Homogeneous Charge Compression Ignition(HCCI) engine according to Exhaust Gas Recirculation(EGR), cylinder-to-cylinder, fuel of propane and butane. HCCI engines are being considered as a future alternative for diesel and gasoline engines. HCCI engines have the potential for high efficiency, very low NOx emissions and very low particulate matter(PM). On experimental work, we have done an evaluation of operating conditions in a 4-cylinder compression engine. The engine has been run with propane and butane fuels at a constant speed of 1800rpm. This work is intended to investigate the HCCI operation of the engine in this configuration that has been modified from the base diesel engine. The performance and emissions of the engine are presented. In this paper, the start of combustion(SOC) is defined as the
point of the peak rate of heat release. SOC is delayed slightly with increasing EGR. As expected, NOx emissions were very low for all EGR range and nbuned HC and CO emission levels were high. CO and HC emissions are lower with using propane than butane as fuels of HCCI engines.