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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 20, Issue 12 - Dec 1996
Volume 20, Issue 11 - Nov 1996
Volume 20, Issue 10 - Oct 1996
Volume 20, Issue 9 - Sep 1996
Volume 20, Issue 8 - Aug 1996
Volume 20, Issue 7 - Jul 1996
Volume 20, Issue 6 - Jun 1996
Volume 20, Issue 5 - May 1996
Volume 20, Issue 4 - Apr 1996
Volume 20, Issue 3 - Mar 1996
Volume 20, Issue 2 - Feb 1996
Volume 20, Issue 1 - Jan 1996
Selecting the target year
Performance Test of a Catapillar Track-Hydroturbine
Lee, Hyeon-Gu ; Kim, Hyeon-Jin ; Kim, Hyeon-Su ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 237~243
DOI : 10.22634/KSME-B.1922.214.171.124
Current low head and small scale hydroturbines have limitations in the minimum required head and flow rate for efficient operation. This study attempts to develop a new concept hydroturbine which is expected to run efficiently even in very low head and small flow rate, so that the limitations on the conventional small scale hydropower could be alleviated and competition with other alternative energy sources in the economic respect could be attained. A small scale catapillar track- hydroturbine was fabricated and the performance test was carried out in a water tunnel over the head range of H = 0.8 m ~ 1.26 m. The peak turbine efficiency was 41.3% at the speed ratio of 0.6, and the turbine loss was mostly due to the friction at the chain drive used for power transmission from the runner to the shafts. This type of turbine is expected to become competitive when some improvement in the power transmission mechanism is made.
A study on the influence of turbulence characteristics on burning speed in swirl flow field
Lee, Sang Jun ; Lee, Jong-Tai ; Lee, Song-Yol ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 244~254
DOI : 10.22634/KSME-B.19126.96.36.199
Flow velocity was measured by, use of hot wire anemometer. Turbulence intensity was in proportion to mean flow velocity regardless of swirl velocity. And integral length scale has proportional relation with swirl velocity regardless of measurement position. Turbulent burning speed during flame propagation which was determined by flame photograph and gas pressure of combustion chamber was increased with the lapse of time from spark and was decreased a little at later combustion period. Because of combustion promotion effect, turbulent burning speed was increased according to increase of turbulence intensity. Burning speed ratio i.e. ratio of turbulent burning speed (
) to laminar burning speed (
) was found out by use of turbulence intensity u' and integral length scale
is width of preheat zone in laminar flame.
Performance Prediction of the Horizontal Axis wind Turbine in Arbitrary Wind Direction
Yu, Neung-Su ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 255~265
DOI : 10.22634/KSME-B.19188.8.131.52
Up to the present the study on the performance prediction of HAWT was performed mainly by assuming the axial flow. So in this paper we aimed at the fully non-axial flow of HAWT. For this purpose, we defined the wind turbine pitch angle in addition to the yaw angle to specify the arbitrary wind direction. And we adopted the Glauert method as the basic analysis method then modified this method suitably for our goal. By comparing the computational results obtained by this modified new Glauert method with the experimental results, it was proved that our method was a very efficient method. And on the basis of the reliability of this method we considered the effect of all the design parameters and presented the optimum blade geometry and the optimum operating condition to gain the best performance curve.
Characteristics of the Onset of Flooding for Countercurrent Air-Water Flow in Vertical Annuli with a Direct Injection Mode
Lee, Sang-Cheon ; Sin, Ik-Ho ; Jeong, Mo ; Jang, Won-Pyo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 266~274
DOI : 10.22634/KSME-B.19184.108.40.2066
An experimental work was conducted to investigate the characteristics of the onset of flooding in vertical annuli with a direct injection mode using air and water. The onset of flooding was determined by means of pressure drop measurement while the air velocity was increased gradually under fixed liquid flow rates. Data of the onset of flooding were collected for various combinations of the tube size and the nozzle number. A theoretical analysis of the onset of flooding was also performed based on an envelope theory. The result shows that the onset of flooding in small-scale annuli can be predicted relatively well by the theory. A modified Wallis parameter was used to investigate the scaling effect of flooding phenomena in the annuli, indicating a relatively reasonable result. The number of nozzle has no effect on the flooding velocity when liquid was injected through 2, 3, 4 and 6 nozzles but the initiation of flooding was significantly expedited when 12 nozzles were employed for liquid injection.
The Fundamental Study on Generation of High Turbulence at Vicinity of Ignition Timing
Hong, Jae-Ung ; Song, Yeong-Sik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 275~283
DOI : 10.22634/KSME-B.19220.127.116.115
The turbulence in the engine cylinder is generated by intake pressure and inertia effects during intake stroke, and is generated and decreased by piston compression effect during the compression stroke. The classified needed to generate high turbulence flow at vicinity of ignition timing. Therefore, A single-shot Rapid Intake Compression Expansion Machine (RICEM), which is able to realize the intake, compression, expansion or intake-compression stroke under high piston speed respectively, was manufactured and evaluated in order to find methods to generate high turbulence at around spark timing. It was found that the characteristics of RICEM such as reapperance, leakage, piston displacement with crank angle was corresponding to those of real engine and RICEM simulates not only high temperature and high pressure field but also flow patterns of the actual engine by increasing of pressure in intake line.
Dynamic Characteristics of Clutch System for an Automatic Transmission
Kim, Ju Hwan ; Kim, Hyun-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 284~294
DOI : 10.22634/KSME-B.1918.104.22.1684
In this paper, dynamic characteristics of an AT clutch system were investigated considering the dynamics of check ball and hydraulic control valves. Dynamic model of a pressure control solenoid valve (PCSV) was obtained by Bondgraph and permeance method. Also, the clutch piston and check ball dynamics were modeled by considering the effect of centrifugal force of the oil entrapped in the clutch chamber. In order to validate the dynamic models obtained, plunger displacement of PCSV and pressure response of the clutch supply lines were compared with the available experimental data, which were in good accordance with the numerical results. Using the dynamic model of the clutch system, simulations were performed to investigate the effect of the rotational speed on the response of clutch cylinder pressure, clutch piston and check ball displacement, and oil flow rate into the cylinder and flow rate out of the check valve.
Temperature Compensation of Hot-Wire Anemometer with Photoconductive Cell
Lee, Sin-Pyo ; Go, Sang-Geun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 295~303
DOI : 10.22634/KSME-B.1922.214.171.1245
A new temperature compensation technique for hot-wire anemometer is proposed in this article. In contrast to the available compensation techniques, a photoconductive cell is introduced here as a variable resistor in the bridge. The major advantage of adopting an active component such as photoconductive cell is that temperature compensation can be achieved by using any kind of temperature sensors, once the output of temperature sensor is given as a voltage. Thereby, the temperature compensation can be made automatically and intelligently by a computer software or a hardware device. Validation experiments using a photoconductive cell with a thermocouple-thermometer are conducted in the temperature range from 3
and the velocity ranges from 8 m/s to 18 m/s.
Development of Multiple Production
Equation Model in Low Reynolds Number
Model with the Aid of DNS Data
Sin, Jong-Geun ; Choe, Yeong-Don ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 304~320
DOI : 10.22634/KSME-B.19126.96.36.1994
A multiple production .epsilon. equation model was developed in the low Reynolds number
model with the aids of DNS data. We derived the model theoretically and avoided the use of empirical correlations as much as possible in order for the model to have generality in the prediction of complex turbulent flow. Unavoidable model constants were, however, optimized with the aids of DNS data. All the production and dissipation models in the
equation were modified with damping functions to satisfy the wall limiting behavior. A new
function, turbulent diffusion and pressure diffusion model for the k and .epsilon. equations were also proposed to satisfy the wall limiting behavior. By, computational investigation on the plane channel flows, we found that the multiple production model for .epsilon. equation could improve the near wall turbulence behavior compared with the standard production model without the complicated empirical modification. Satisfication of the wall limiting conditions for each turbulence model term was found to be most important for the accurate prediction of near wall turbulence behaviors.
An Experimental Study on the Combustion Phenomena in Porous Media
Lee, Yong-Il ; Sin, Hyeon-Dong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 321~327
DOI : 10.22634/KSME-B.19188.8.131.521
Experiments were performed on the laminar premixed flame stabilized in a porous medium to know whether the flame downstream of the combustor exists or not. In previous theoretical studies, a stable flame has been predicted in the downstream region of the combustor, but it has never been observed in experiments. In this study, a stable downstream flame could be obtained for the lower burning velocity through circumferential heating by a blue flame positioned outside the periphery of the specially devised combustor. The existence of the stable downstream flame was confirmed by a direct photography of soot line, and temperature measurements. The effect of combustor diameter to flame stability was also considered. As the diameter of the combustor increases, the lean flammability limit was extended.
A Numerical Study on the Combustion Phenmena in Porous Media( I )
Lee, Yong-Il ; Sin, Hyeon-Dong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 328~335
DOI : 10.22634/KSME-B.19184.108.40.2068
The one-dimensional flame analysis was carried out to understand the combustion phenomena in porous media. The downstream as well as upstream solution corresponding to upper and lower solutions could be obtained. While upper flame temperature gets higher, lower flame temperature gets lower, as the flame approaches the central part of the combustor. The reason why upstream flame and downstream flame exist at the same flow condition is that the regions where net heat recirculation is identical exist in upstream and downstream of the combustor. In order for the downstream flame to be stabilized, more heats needed to be recirculated towards upstream because of larger radiation loss of downstream flame.
A Theoretical and Experimental Study for the Design of Solar Air Heaters Using Porous Material
Hwang, Yong-Ha ; Park, Seung-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 336~345
DOI : 10.22634/KSME-B.19220.127.116.116
A theoretical and experimental study was conducted in order to design highly efficient solar air heaters using porous material. Radiative characteristics of glass windows and porous absorbing media were correlated through spectral transmittances measured by the UV-Visible and the FT-IR spectrometers. Using those characteristics the efficiencies of collectors were numerically calculated with the use of the two-flux radiation model. Based on the theoretical results, an experimental solar collector was designed and constructed. Experimental results under various conditions show that the daily efficiencies are over 60% in general and agree well with the theoretically calculated ones.
Analysis of Radiative-Convective Heat Transfer about a Circular Cylinder in Crossflow Using Finite Volume Radiation Solution Method
Lee, Gong-Hun ; Lee, Jun-Sik ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 346~358
DOI : 10.22634/KSME-B.1918.104.22.1686
A finite volume radiation solution method was applied to a non- orthogonal coordinate system for the analysis of radiative-convective heat transfer about a circular cylinder in crossflow. The crossflow Reynolds number based on the cylinder radius was 20, and the fluid Prandtl number was 0.7. The radiative heat transfer coupled with convection was reasonably predicted by the finite volume radiation solution method. The investigation includes the effects of conduction- to-radiation parameter, optical thickness, scattering albedo and cylinder wall-emissivity on heat transfer about the cylinder. As the conduction- to-radiation parameter decreases, the radiative heat transfer rate increases and conduction rate as well due to the increase in temperature gradient on the cylinder wall which is caused by radiation enhancement. With an increase in the optical thickness, the Nusselt number increases significantly and the temperature gradient shows similar behavior. Though the radiative heat transfer increases with the scattering albedo, the total heat transfer decreases. This is because the decrease in the conduction heat transfer exceeds the increase in the radiation heat transfer. As the wall- emissivity increases, the radiation absorbed in the vicinity of the cylinder wall increases and thereby the total heat transfer increases, even though the conduction heat transfer decreases.
A Study on an Improvement of the Ignitability Using the High Frequency Ignition System
Lee, Jung-Sun ; Gang, Byeong-Mu ; Ha, Jong-Ryul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 359~368
DOI : 10.22634/KSME-B.1922.214.171.1249
For fuel economy and pollutant reduction, the interests in lean burn has increased recently. The purpose of this research is to develop a High Frequency Ignition System (HIS) that can make powerful ignition. We studied relations between performance of HIS and probability of inflammation under various ignition conditions. It is concluded that the portion of capacitance energy to the total energy is comparatively larger and that the optimum spark interval and spark duration are dependent upon conditions of Constant Volume Combustion Chamber.
Drag and Lift Forces of a Circular Cylinder Located Parallel to a Planar Jet
Gang, Sin-Hyeong ; Hong, Sun-Sam ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 369~376
DOI : 10.22634/KSME-B.19126.96.36.1999
Variations of the drag and lift forces of a circular cylinder in a planar turbulent jet were experimentally investigated. The force was directly measured using the load cell and estimated by integrating the pressure distribution on the cylinder. As the cylinder moves outward from the center of the jet, the direction of lift force changes and the drag force decreases. Reynolds number, the ratio of cylinder's diameter to half width of jet had effect on maximum drag coefficient and the location where the direction of lift changes.
A Numerical Study on the Lean-Rich Interaction of Methane/Air Flames
Lee, Seung-Dong ; Jeong, Seok-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 377~383
DOI : 10.22634/KSME-B.19188.8.131.527
Interaction of flames in a lean-rich concentration field is studied numerically adopting a counterflow as a model problem. Detailed kinetic mechanism is adopted in analyzing the structure of various type of flames which can be found in lean-rich interaction. Flow field is simplified to quasi one-dimensional by using boundary layer approximation and similarity formulation. Triple flames are identified and its structure shows that a diffusion flame is located in the middle of two premixed flames. Such a diffusion flame is formed by
and CO generated from the rich premixed flame and
leaked from the lean premixed flame. The flame position can be identified either from the hydrogen production rate or the heat release rate. Transition from single diffusion flame to triple flame is observed as degree of premixing is increased.
Void Fraction Measurement by the Improved Multi-Channel Impedance Void Meter
Song, Cheol-Hwa ; Jeong, Mun-Gi ;
Transactions of the Korean Society of Mechanical Engineers B, volume 20, issue 1, 1996, Pages 384~398
DOI : 10.22634/KSME-B.19184.108.40.2064
An improved multi-channel Impedance Void Meter (IVM) is developed to measure an area-averaged void fraction. It consists of a main sensor, a reference sensor and a signal processor. The sensor was designed to be flush-mounted to the inner wall of the test section to avoid the flow disturbances. Guard electrodes are used to obtain evenly distributed electrical field in a measuring volume. A reference sensor is also installed to eliminate the drift in void signal caused by the changes in electrical properties of working fluid. The signal processor with three channels is specially designed so as to minimize the inherent error due to the phase difference between channels. As an example of applications, the mean and fluctuating components of void fraction are measured for bubbly and slug flow regime, and it is shown that IVM has good dynamic resolution which is required to investigate the structural developments of bubbly flow and the propagation of void waves in a flow channel.