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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 27, Issue 12 - Dec 2003
Volume 27, Issue 11 - Nov 2003
Volume 27, Issue 10 - Oct 2003
Volume 27, Issue 9 - Sep 2003
Volume 27, Issue 8 - Aug 2003
Volume 27, Issue 7 - Jul 2003
Volume 27, Issue 6 - Jun 2003
Volume 27, Issue 5 - May 2003
Volume 27, Issue 4 - Apr 2003
Volume 27, Issue 3 - Mar 2003
Volume 27, Issue 2 - Feb 2003
Volume 27, Issue 1 - Jan 2003
Selecting the target year
Performance Design Analysis of Hybrid Systems Combining Atmospheric Pressure Molten Carbonate Fuel Cell and Gas Turbine
Jeong, Young-Hyun ; Kim, Tong-Soep ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1361~1369
DOI : 10.3795/KSME-B.2003.27.10.1361
Design performance of hybrid power generation systems, comprised of a gas turbine and an atmospheric pressure molten carbonate fuel cell, has been analyzed. Two different configurations were analyzed and performances were compared. A reference calculation was performed for the design condition of a system under development and simulated results agreed well with the published data. Performances were analyzed in terms of main design parameters including turbine inlet temperature, operating temperature of the fuel cell and pressure ratio. Also examined were the effects of fuel utilization factor and heat exchanger effectiveness. It was found that the relationship between the turbine inlet temperature and the fuel cell temperature should be critically examined to evaluate achievable design performance. Considering current state of the art technologies, a system with the combustor located before the turbine could achieve higher efficiency and specific power than the other system with the combustor located after the turbine.
Investigation of the Liquid Fuel Film Behavior on the Cylinder Liner in an SI Engine
Cho, Hoon ; Hwang, Seumg-Hwang ; Lee, Jong-Hwa ; Min, Kyoung-doug ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1370~1376
DOI : 10.3795/KSME-B.2003.27.10.1370
The investigation of liquid fuel film on the cylinder liner is an essential to understand the engine-out hydrocarbon emissions formation in SI engines. In this research, two-dimensional visualization was carried out to investigate the liquid fuel film on the quartz liner in the optical engine. For this, the optical engine with hydraulic system was designed based on the commercial SI engine. The visualization was based on the laser-induced fluorescence with total reflection technique. Using a quartz liner and a special lens, only the liquid fuel film on the liner was visualized. With using this technique, the distribution of the fuel film on the cylinder liner was measured for different engine conditions and injection timing in the optical engine.
Faultproof Design in Space for Monopropellant Rocket Engine Assembly
Han, Cho-Young ; Kim, Jeong-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1377~1384
DOI : 10.3795/KSME-B.2003.27.10.1377
An analysis has been performed for active thermal control of the KOMPSAT monopropellant rocket engine assembly, i.e., dual thruster module(DTM). The main efforts of this work have been directed at determining proper heater sizes for propellant valves and catalyst beds necessary to maintain their temperatures within specified temperature ranges under KOMPSAT environment and operational conditions. The TAS incorporated with TRASYS thermal radiation analyzer was used to establish a complete heat transfer model which allows to predict the DTM temperature as a function of time. The thermal analysis has been performed in transient mode to verify the appropriate power for catalyst bed heaters necessary to increase catalyst bed temperature to the required value within a specified period of time. Similar analysis has been executed to validate the heater power for the thermostatically controlled primary and redundant heater circuits used to prevent hydrazine freezing, i.e., single fault. Moreover the effect of the radiative property of thermal control coating of heat shield was examined. Thruster firing condition was also simulated for the heat soakback condition. As a consequence, all thermal analysis results for DTM satisfactorily met the thermal requirements for the KOMPSAT DTM under the worst case average voltage, i.e. 25 volt.
Design and Fabrication of an Electromagnetic Flowmeter
Lim, Ki-Won ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1385~1392
DOI : 10.3795/KSME-B.2003.27.10.1385
An electromagnetic flowmeter(EMF) was developed and its characteristics were compared with a commercial EMF. The developed EMF was designed as the 100 mm nominal diameter. A signal processing circuit was also developed for generating the magnetic field and converting the flow signal to flowrate and flow quantity. In order to obtain a more stable and reliable flow signal, the double magnetizing frequency was adopted for magnetizing the coil of the EMF. For the characterization of the developed EMF, the uncertainty of calibrator was estimated within
0.5 %. The evaluation procedure of the uncertainty followed the ISO Guide to the Expression of Uncertainty in Measurement. It was found that the flow signals between the electrodes were about
V, which were sufficient for the discrimination of flowmeter and the protection of noise. The test results against the calibrator showed the good linearity in the range of 3 ㎥/h and 70 ㎥/h. A commercialized design of the EMF based on the current study will be technically more competitive in domestic and foreign market.
Asymptotic Analysis on the Stagnation-Point Ignition of Hydrogen-Oxygen Mixture at High Pressures
Lee, Su-Ryong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1393~1400
DOI : 10.3795/KSME-B.2003.27.10.1393
Ignition of hydrogen and oxygen in the "third limit" is theoretically investigated in the stagnation point flow with activation energy asymptotics. With the steady-state approximations of H, OH, O and HO
, a two-step reduced kinetic mechanism is derived for the regime lower than the crossover temperature T
at which the rates of production and consumption of all radicals are equal. Appropriate scaling of Damkohler number successfully provides the explicit relationship between pressure, temperature and strain rate at ignition. It is shown that, compared with those for the counterflow, ignition temperatures for the stagnation point flow are considerably increased with increasing the system pressure. This is because ignition in the "third limit" is characterized by the production of reduction of
, which is reduced by wall effect. Strain rate substantially affects ignition temperature because key reaction rates of
are comparably with its transport rate, while the mixture temperature and the hydrogen composition do not significantly affect ignition temperature.e.
Extinction in a Counterflow Nonpremixed Flame Interacting with a Vortex
Oh, Chang-Bo ; Lee, Chang-Eon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1401~1411
DOI : 10.3795/KSME-B.2003.27.10.1401
A two-dimensional direct numerical simulation was performed to investigate the flame structure of CH
-air counterflow nonpremixed flame interacting with a single vortex. The detailed transport properties and a modified 16-step augmented reduced mechanism based on Miller and Bowman`s detailed chemistry were adopted in this simulation. The characteristic vortex and chemical time scales were introduced to quantify and investigate the extinction phenomenon during a flame-vortex interaction. The results showed that fuel- and air-side vortex cause an unsteady extinction. In this case, the flame interacting with a vortex was extinguished at much larger scalar dissipation rate than steady flame. It was also found that the air-side vortex extinguished a flame more rapidly than the fuel-side vortex. Furthermore, it was noted that the degree of unsteady effect experienced by a flame can be investigated by comparing the above two characteristic time scales, and this analysis could give an appropriate reason for the results of the previously reported experiment.
Derivation of Design Parameter for Heat Regenerator with Spherical Particles
Cho, Han-Chang ; Cho, Kil-Won ; Lee, Yong-Kuk ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1412~1419
DOI : 10.3795/KSME-B.2003.27.10.1412
Heat regenerator occupied by regenerative materials improves thermal efficiency of combustion system through the recovery of sensible heat of exhaust gases. By using one-dimensional two-phase fluid dynamics model, the unsteady thermal flow of regenerator with spherical particles, was numerically analyzed to evaluate the heat transfer and pressure losses and to derive the design parameter for heat regenerator. It is confirmed that the computational results, such as air preheat temperature, exhausted gases outlet temperature, and pressure losses, agreed well with the experimental data. The thermal flow in heat regenerator varies with porosity, configuration of regenerator and diameter of regenerative particle. As the gas velocity increases with decreasing the cross-sectional area of the regenerator, the heat transfer between gas and particle enhances and pressure losses decrease. As particle diameter decreases, the air is preheated higher and the exhaust gases are cooled lower with the increase of pressure losses. Assuming a given exhaust gases temperature at the regenerator outlet, the regenerator need to be linearly lengthened with inlet Reynolds number of exhaust gases, which is defined as a regenerator design parameter.
Stability Enhancement by the Interaction of Diffusion Flames
Kim, Jin-Sun ; Lee, Byeong-Jun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1420~1426
DOI : 10.3795/KSME-B.2003.27.10.1420
The stability of turbulent nonpremixed interacting flames is investigated in terms of nozzle configuration shapes and kind of fuels. Four nozzle arrangements - cross 5, matrix 8, matrix 9 and circle 8 nozzles - are used in the experiment. There are many parameters affecting flame stability in multi-nozzle flames such as nozzle separation distance, fuel flowrates and nozzle configuration etc. Key factors to enhance blowout limit are the nozzle configuration and the existence of center nozzle. Even nozzle exit velocity equal 204 m/s, flame is not extinguished when there is not a center nozzle and s/d
Development of a Screw Type Super-Charger for Part Load Control of Passenger Car
Bea, Jae-Il ; Bae, Sin-Chul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1427~1434
DOI : 10.3795/KSME-B.2003.27.10.1427
Turbo- or Super-charging has been used to boost engine power for Gasoline- and Diesel Engine since beginning of 20th century. So far turbo-charger has enjoyed a high reputation in the charging field for its technical advantages such as no demand of operation power from engine and an excellent charging effect in a static operation at mid- and high engine speed. A mechanically driven super-charger, however, is now popular due to the high engine power at quick change of the driving mode - high engine torque even at low engine speed. Since super-charger needs operation power from engine, it is difficult to improve its relatively higher fuel consumption than that of turbo-charger. This negative point is still an obstacle to the wide use of supercharger. Super-charger using screw-type compressor will fulfill the purpose to reduce fuel consumption by minimizing operation power owing to no charge at idling or part load driving condition. This study aims to develop power control concept to achieve the minimization of operation power. A screw type super-charger was modified in design partially and installed with an internal bypass valve and a bypass tube to control charging pressure at part load. The various control concepts show a possibility to reduce operation power of super-charger.
A Study on Combustion Characteristics of Diesel-water Emulsion with High Pressure Injection
Jeong, Dae-Yong ; Lee, Jong-Tai ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1435~1441
DOI : 10.3795/KSME-B.2003.27.10.1435
Combustion characteristics on diesel-water emulsion are analyzed in high pressure injection for several variables such as water content, injection pressure and injection timing. As a fact of well-known, maximum combustion pressure was decreased and ignition delay was elongated in accordance with increasing of water content. But these characteristics were enhanced with increase of injection pressure to high pressure. It was shown that combustion of neat diesel in case of injecting with 600bar is similar to that of 20 % diesel-water emulsion was injected at 1200 bar.
Generation Characteristics of Ozone and NO
and Particle Removal in the Electrostatic Precipitators
Noh, Kwang-Chul ; Lee, Young-Ho ; Oh, Myung-Do ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1442~1449
DOI : 10.3795/KSME-B.2003.27.10.1442
We investigated the amount of the toxic gases emitted from the Electrostatic Precipitators(ESPs), which are currently used as the indoor air cleaners. The existing wire-to-plate(WTP) and neddle-to-plate(NTP) types of ESP designs are considered as the experimental corona dischargers. Using the voltage, the polarity of wire, the number of needles of NTP as the input variables, we studied the generation characteristics of ozone and
and the particle removal efficiency in the ESPs. As the results, we found out that the concentration of ozone,
is increased with increasing the voltage and the number of needles, but the amount of NO is decreased. And we observed that the generation rates of ozone and
are mainly related with the corona region through the photographs. Finally the experimental results showed that the particle removal efficiency of ESP with WTP type charger is more superior to that with NTP type chargers at the same voltage.
Numerical Study on the Effects of Velocity Profile Distortion and Swirl on Pressure Difference of Orifice Flowmeter Due to Pipe structure
Kim, Hong-Min ; Kim, Kwang-Yong ; Her, Jae-Young ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1450~1456
DOI : 10.3795/KSME-B.2003.27.10.1450
Three-dimensional pipe flows with elbows, tees and headers in three different pipe systems are calculated to estimate the effect of asymmetry of axial velocity profile and swirl on measuring accuracy of an orifice flowmeter. It is evaluated how the pressure difference across the orifice is dependent on the upstream straight pipe length and how swirl intensity, swirl angle, and axial velocity distribution affect the measuring error of the orifice flowmeter. From the results, it is found that variation of the pressure difference across the orifice is negligible in case that maximum swirl angle is less than 2
, and also that the pressure difference across the orifice is more sensitive to the asymmetry of axial velocity profile rather than the swirl intensity.
Design Optimization of A Multi-Blade Centrifugal Fan with Navier-Stokes Analysis and Response Surface Method
Seo, Seoung-Jin ; Kim, Kwang-Yong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1457~1463
DOI : 10.3795/KSME-B.2003.27.10.1457
In this paper, the response surface method using three-dimensional Navier-Stokes analysis to optimize the shape of a multi-blade centrifugal fan, is described. For numerical analysis, Reynolds-averaged Navier-Stokes equations with standard k - c turbulence model are transformed into non-orthogonal curvilinear coordinate system, and are discretized with finite volume approximations. Due to the large number of blades in this centrifugal fan, the flow inside of the fan is regarded as steady flow by introducing the impeller force models for economic calculations. Linear Upwind Differencing Scheme(LUDS) is used to approximate the convection terms in the governing equations. SIMPLEC algorithm is used as a velocity-pressure correction procedure. Design variables, location of cur off, radius of cut off, expansion angle of scroll and width of impeller were selected to optimize the shapes of scroll and blades. Data points for response evaluations were selected by D-optimal design, and linear programming method was used for the optimization on the response surface. As a main result of the optimization, the efficiency was successfully improved. It was found that the optimization process provides reliable design of this kind of fans with reasonable computing time.
Flow Analysis of POSRV Subsystem of Standard Korean Nuclear Reactor
Kwon, Soon-Bum ; Kim, In-Goo ; Ahn, Hyung-Joon ; Lee, Dong-Eum ; Baek, Seung-Cheol ; Lee, Byeong-Eun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1464~1471
DOI : 10.3795/KSME-B.2003.27.10.1464
In order to investigate the flows with shock wave in branch, 108
elbow and T-junction of the IRWST system of standard Korean nuclear reactor, detail time dependent behaviors of unsteady flow with shock wave, vortex and so on are obtained by numerical method using compressible three-dimensional Navier-Stokes equations. At first, the complex flow including the incident and reflected shock waves, vortex and expansion waves which are generated at the corner of T-junction is calculated by the commercial code of FLUENT6 and is compared with the experimental result to obtain the validation of numerical method. Then the flow fields in above mentioned units are analyzed by numerical method of [mite volume method. In numerical analysis, the distributions of flow properties with the moving of shock wave and the forces acting on the wall of each unit which can be used to calculate the size of supporting structure in future are calculated specially. It is found that the initial shock wave of normal type is re-established its type from an oblique one having the same strength of the initial shock wave at the 4 times hydraulic diameters of downstream from the branch point of each unit. Finally, it is turned out that the maximum force acting on the pipe wall becomes in order of the T-junction, 108
elbow and branch in magnitude, respectively.
Noise Reduction of an Underexpanded Supersonic Jet via Steady Blowing with Microjets
Kim, Jin-Hwa ; Kim, Jung-Hoon ; Yoo, Jung-Yul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1472~1479
DOI : 10.3795/KSME-B.2003.27.10.1472
An attempt to reduce supersonic jet noise is carried out by using two steady microjets in a round jet. The jet is issued from a round sonic nozzle with an exit diameter of 10 mm. Two micro-nozzles with an inside diameter of 1 mm each are installed on the exit plane at an angle of 45 relative to the main jet axis. Far-field noise was measured at 40 diameters off the jet axis. The angle between a microphone and the jet axis is 30 or 90
. For an injection rate of 4-6% of the main jet, screech tones were completely suppressed by the microjets. The reduction in the overall sound pressure levels were 2.4 and 2.7 dB for 90 and 30 measuring directions, respectively. However, the enhancement of mixing/spreading of the jet by the microjet was negligible. The reduction of noise is probably due to distorted shock cell structures and/or deformed large scale vortical structures by the microjets.
Synthesis of Carbon Nanotubes and Nanofibers on a Substrate Coated with Metal Nitrates using an C
Inverse Diffusion Flame
Lee, Gyo-Woo ; Jurng, Jong-Soo ; Hwang, Jung-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1480~1488
DOI : 10.3795/KSME-B.2003.27.10.1480
Synthesis of carbon nanomaterials on a substrate coated with metal nitrates using an ethylene fueled inverse diffusion flame was illustrated. The effects of radial distance, residence time of the substrate, and hydrocarbon composition on the synthesis of carbon nanomaterials were investigated. The effects of catalyst metal particles were also studied using SUS304 substrates coated with Fe(NO
(ferric nitrate, nonahydrate) and Ni(NO
(nickel nitrate, hexahydrate), and Cu substrate. Carbon nanomaterials, with diameters ranging from 30 - 70 nm, were observed on the substrate for both cases of using substrates only and using them with metal nitrates. In case of using the substrate with metal nitrates, the formation and growth of carbon nanomaterials were occurred in the lower temperature region than that of using the substrates only due to the easy activation of the metal particles coated on the surface of the substrates.
Nano Particle Charging Characteristics of Aerosol Charge Neutralizers
Ji, Jun-Ho ; Bae, Swi-Nam ; Hwang, Jung-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1489~1497
DOI : 10.3795/KSME-B.2003.27.10.1489
Aerosol charge neutralizers with various radioactive sources have been used to apply an equilibrium charge distribution to aerosols of unknown charge distribution. However, the performance of aerosol charge neutralizers is not well known, especially for highly charged particles. Measurements of highly charged particles are needed in air cleaning devices, e.g. electrostatic precipitator, bag filter with a pre-charger, and electrical cyclone. In this study, the particle charging characteristics of two different aerosol charge neutralizers were experimentally investigated for singly charged monodisperse particles and highly charged polydisperse particles. One has radioactive source of
Kr (beta source, 2 mCi) and the other has
Po (alpha source, 0,5 mCi). The air flow rate passing through each aerosol charge neutralizer was changed from 0.2 to 2.5 L/min. The results show that the charge distribution of singly charged monodisperse particles passing through the
Kr aerosol charge neutralizer is well agreed with the Boltzmann equilibrium charge distribution at an air flow rate of 0.3 L/min, However, it deviates from the equilibrium charge distribution when the air flow rates are 0.6, 1,0, and 1,5 L/min, On the other hands, the effect of air flow rate is insignificant for the
Po aerosol charge neutralizer. The non-equilibrium character in charge distribution of highly charged polydisperse particles passing through the
Kr aerosol charge neutralizer greatly depends on the air flow rate, however it is insensitive to the air flow rate for the
Po aerosol charge neutralizer.
Effect of Performance of Aerosol Charge Neutralizers on the Measurement of Highly Charged Particles Using a SMPS
Ji, Jun-Ho ; Bae, Swi-Nam ; Hwang, Jung-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1498~1507
DOI : 10.3795/KSME-B.2003.27.10.1498
A SMPS(scanning mobility particle sizer) system measures the number size distribution of particles using electrical mobility detection technique. An aerosol charge neutralizer, which is a component of the SMPS, is a bipolar charger using a radioactive source to apply an equilibrium charge distribution to aerosols of unknown charge distribution. However, the performance of aerosol charge neutralizers is not well known, especially for highly charged particles. In this study, the effect of the particle charging characteristics of two aerosol charge neutralizers on the measurement using a SMPS system was experimentally investigated for highly charged polydisperse particles. One has radioactive source of
Kr (beta source, 2 mCi) and the other has
Po (alpha source, 0.5 mCi). The air flow rate passing through each aerosol charge neutralizer was changed from 0.3 to 3.0 L/min. The results show that the non-equilibrium character in particle charge distribution appears as the air flow rate increases although the particle number concentration is relatively low in the range of 1.5∼2x10
particles/㎤. The low neutralizing efficiency of the
Kr aerosol charge neutralizer for highly charged particles can cause to bring an artifact in the measurement using a SMPS system. However, the performance of the
Po aerosol charge neutralizer is insensitive to the air flow rate.
Shape Detection of Ellipsoidal Droplets Using Randomized Hough Transform
Choo, Yeon-Jun ; Kang, Bo-Seon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1508~1515
DOI : 10.3795/KSME-B.2003.27.10.1508
In this study, the image processing program for deducing parameters of the elliptic shape of the partially overlapped liquid droplets was developed using the randomized Hough transform and the parameter decomposition. The procedure for the shape detection consists of three steps. For the first step, the candidate centers of ellipses are determined by the geometric property of the ellipse. Next, the rest parameters are estimated by the randomized Hough transform. In the final step for the post-processing, optimally approximated parameters of ellipses are determined. The developed program was applied to the simulated overlapped ellipses, real overlapped droplets, and real spray droplets. The shape detection was very excellent unless there existed inherent problems in original images. Moreover, this method can be used as an effective separating method for the overlapped small particles.
A Study on a Hybrid Genetic Algorithm for the Analysis of Inverse Radiation
Kim, Ki-Wan ; Baek, Seung-Wook ; Kim, Man-Young ; Ryou, Hong-Sun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 27, issue 10, 2003, Pages 1516~1523
DOI : 10.3795/KSME-B.2003.27.10.1516
An inverse radiation analysis is presented for the estimation of the boundary emissivities for an absorbing, emitting, and scattering media with diffusely emitting and reflecting opaque boundaries. The finite-volume method is employed to solve the radiative transfer equation for a two-dimensional irregular geometry. A hybrid genetic algorithm is proposed for improving the efficiency of the genetic algorithm and reducing the effects of genetic parameters on the performance of the genetic algorithm. After verifying the performance of the proposed hybrid genetic algorithm, it is applied to inverse radiation analysis in estimating the wall emissivities in a two-dimensional irregular medium when the measured temperatures are given at only four data positions. The effect of measurement errors on the estimation accuracy is examined.