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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 21, Issue 12 - Dec 1997
Volume 21, Issue 11 - Nov 1997
Volume 21, Issue 10 - Oct 1997
Volume 21, Issue 9 - Sep 1997
Volume 21, Issue 8 - Aug 1997
Volume 21, Issue 7 - Jul 1997
Volume 21, Issue 6 - Jun 1997
Volume 21, Issue 5 - May 1997
Volume 21, Issue 4 - Apr 1997
Volume 21, Issue 3 - Mar 1997
Volume 21, Issue 2 - Feb 1997
Volume 21, Issue 1 - Jan 1997
Selecting the target year
Study on the characteristics of laminar lifted flames using planar laser induced fluorescence technique
Lee, Byeong-Jun ; Jeong, Seok-Ho ; Han, Jae-Won ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1393~1402
DOI : 10.22634/KSME-B.19126.96.36.1993
Characteristics of the lifted flame which is generated by issuing of the fuel through the miniature nozzle, d = 0.164 mm, are studied using the planar laser induced fluorescence technique. OH radical is excited on the
(8) line of the
.PI.(1, 0) band transition (283.55 nm) and LIF signals are captured at the bands of (0, 0) and (1, 1) transition (306 ~ 326 nm) using the filters and ICCD camera. Hydroxyl radical (OH) profile for nozzle attached flame shows that OH radical populations at the flame sides and flame tip are larger than those at the base. But for the lifted flame (tribrachial flame) case, those are larger at the flame base than at the flame tip and flame sides. The OH radical is more dense near the center line of flame base at the blowing out. This fact proves the Chung and Lee's blowout theory-blowout occurs when the flame is anchored at the flame axis. axis.
Numerical Study of Compression Waves Propagating Through Porous Walls
Kim, Hui-Dong ; Setoguchi, Toshiaki ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1403~1412
DOI : 10.22634/KSME-B.19188.8.131.523
When a high-speed railway train enters a tunnel, a compression wave is generated ahead of the train and propagates through the tunnel, compressing and accelerating the rest air in front of the wave. At the exit of the tunnel, an impulsive wave is emitted outward toward the surrounding, which causes a positive impulsive noise like a kind of sonic boom produced by a supersonic aircraft. With the advent of high-speed train, such an impulsive noise can be large enough to cause the noise problem, unless some attempts are made to alleviate its pressure levels. In the purpose of the impulsive noise reduction, the present study calculated the effect of porous walls on the compression wave propagating into a model tunnel. Two-dimensional unsteady compressible equations were differenced by using a Piecewise Linear Method. Calculation results show that the cavity/porous wall system is very effective for a compression wave with a large nonlinear effect. The porosity of 30% is most effective for the reduction of the maximum pressure gradient of the compression wave front. The present calculation results are in a good agreement with experimental ones obtained previously.
Numerical study on the interaction between unsteady compression and unsteady expansion wave
Kim, Hui-Dong ; Setoguchi, Toshiaki ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1413~1421
DOI : 10.22634/KSME-B.19184.108.40.2063
A new control method to alleviate the impulsive noise at the exit of high-speed railway tunnel was applied to the compression wave at the entrance of the tunnel. This method uses the interaction phenomenon of unsteady expansion wave and unsteady compression wave. Unsteady expansion wave was assumed to be made instantaneously by the simple theory of shock tube. Total Variation Diminishing method was employed to solve the axisymmetric unsteady compressible flow field with a specified compression wave. Numerical results show that the maximum pressure gradient of the propagating compression wave decreases with increase of the wave length of the unsteady expansion wave. It is found that the impulsive noise reduction can be obtained when the unsteady expansion wave with a large wave length is emitted just before the train enters the tunnel. The present results give the possibility to reduce the impulsive noise at the exit of tunnel.
Numerical study of double diffusive convection due to lateral heating in a rotating annulus
Gang, Sin-Hyeong ; Lee, Gyo-Seung ; Lee, Jin-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1422~1436
DOI : 10.22634/KSME-B.19220.127.116.112
Numerical investigations were conducted to study the convective phenomena of an initially stably stratified salt water solution with lateral heating in a uniformly rotating annulus. The method of investigation is the finite difference analysis of the basic conservation equation for an axisymmetric, unsteady, double-diffusive convection and calculation is made for R
. Formation of layered flow structure, merging process of layers, the corresponding temperature and concentration distributions, Nu variation with time are examined. Numerical results show that in each layer, the temperature profile looks 'S'-shaped and the concentration profile is uniform due to the convective mixing. At the interface between adjacent layers, the temperature changes smoothly but the concentration changes rapidly. As the effect of the rotation increases, the generation of rolls at hot wall, the formation and merging of layers are delayed. The average Nu shows the trend of conduction heat transferees the effect of the rotation increases.n increases.
Full angle range pressure coefficient maps of five-hole probe and new calibration coefficients
Kim, Jin-Gwon ; Gang, Sin-Hyeong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1437~1448
DOI : 10.22634/KSME-B.1918.104.22.1687
Pressures of a five-hole probe were measured for a full range of yaw and pitch angles and complete pressure coefficient maps were obtained. Based on these maps, various features of five-hole probe pressures were revealed and new five-hole probe calibration coefficients were devised. The new calibration coefficients show non-diverging characteristics for any flow direction and one-to-one correspondence for a wide range of flow angles. These calibration coefficients expand the valid flow angle range of five-hole probe calibration by .+-.10 degrees and complement a critical defect of five-hole probe zone-division calibration method which has not been known yet. Moreover new non-diverging calibration coefficients have advantages in nulling methods, too.
Development of five-hole probe nulling method reliable in complex flow field
Kim, Jin-Gwon ; Gang, Sin-Hyeong ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1449~1457
DOI : 10.22634/KSME-B.1922.214.171.1249
Since a non-nulling method of five-hole probes is valid only when the flow angle is within the calibrated angle range, it can not be used in a complex flow field. Full angle range pressure coefficient maps show that widely used nulling methods do not guarantee correct alignment of the probe with the flow direction in the unknown complex flow field. Zone decision method and features of zone map were studied by investigating the full angle range pressure coefficient maps. A reliable and efficient new nulling algorithm using zone decision by pressure ordering is proposed and verified. Since the zone decision method by pressure ordering can decide whether the flow is within the calibration angle range or not, it is useful in wide angle nonnulling methods, too.
A study on the effect of injection pressure and ambient pressure for the growth of impinging spray
Cha, Geon-Jong ; Seo, Gyeong-Il ; Kim, Deok-Jul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1458~1465
DOI : 10.22634/KSME-B.19126.96.36.1998
This study investigated the effects of pressure on the growth of an impinging spray. We obtained the frozen images which were scattered by Nd ; YAG laser light (pulse width : 7 ns) using synchronization circuit made in the laboratory. For an impinging spray a growth of the penetration length was progressed with increase of the injection pressure but an ambient pressure restrained its growth. The effect of an ambient pressure on penetration was larger than that of an injection pressure. The pressure ratio had an effect on the penetration growth rate. The thickness growth rate depended on both the injection pressure and the ambient pressure compositively. A lower injection pressure or a higher ambient pressure was required for spatial distribution of impinging spray.
Experimental study on the heat flux and heat transfer coefficient in a spark ignition engine
Han, Seong-Bin ; Gwon, Yeong-Jik ; Lee, Jeong-Yeol ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1466~1474
DOI : 10.22634/KSME-B.19188.8.131.526
In order to design and develop a spark ignition engine, many studies must be preceded about the characteristics of thermal flow. For measurement of transient wall temperature thin film thermocouples of Bendersky type were manufactured and these probes were fixed into the wall of combustion chamber. Surface wall temperatures were measured in experiments of various engine speeds. Transient heat fluxes were calculated from the wall temperature measurements. Pressure was measured from combustion chamber using pressure transducer and gas temperatures were calculated using the state equation of ideal gas. And instantaneous heat transfer coefficients were obtained. It will be the basic data for the formulae of instantaneous heat transfer coefficients.
Determination of empirical formula for instantaneous heat transfer coefficients in a S. I. engine
Han, Seong-Bin ; Gwon, Yeong-Jik ; Lee, Jeong-Yeol ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1475~1484
DOI : 10.22634/KSME-B.19184.108.40.2065
A new empirical formula for instantaneous heat transfer coefficients was determined. The determination of this formula is in need for prediction of instantaneous value of heat transfer coefficients to analyze in more detail the time variation of heat transfer rate from gas to wall in combustion chamber of a spark ignition engine. As the result, following formula was determined. h=687
(1.35 p dV/d.theta.+V dp/d.theta.) Using this empirical formula, the instantaneous heat transfer coefficients of gas in the combustion chamber of spark ignition engine was predicted and compared with experimental values.
Heat (mass) transfer measurement and analysis with flows around film cooling holes and circular cylinders
Kim, B.G. ; Wu, S. J. ; Cho,H. H. ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1485~1495
DOI : 10.22634/KSME-B.19220.127.116.115
The present study investigates heat/mass transfer around film cooling jets and circular cylinders to compare the characteristics of each other. Experiments are conducted to obtain the detailed heat/mass transfer coefficients of flat plate with injections through an array of holes and for flows around an array of protruding circular cylinders using the naphthalene sublimation technique. The inclination angles of cylinders are set to the same ones of jets; a, the angle between the jet and the surface is fixed at 30 deg. through the whole experiments and .betha., the angle between the projection of the jet on the surface and the direction of main stream is adjusted to 0 deg., 45 deg. and 90 deg. to investigate the effect of variation of injection angles. The influence of blowing rates of jets and those of cylinder length to diameter ratios are also investigated. The results indicate that the increase of angle .betha. influences the spanwise uniformity of heat/mass transfer remarkably for both jets and cylinders, but that variation of cylinder length to diameter ratios has weaker effects on heat/mass transfer coefficients than that of blowing rates.
Wind Engineering Study on the Surface-Pressure Characteristic of a Triangular Prism Located Behind a Porous Fence
Park, Cheol-U ; Lee, Sang-Jun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1496~1508
DOI : 10.22634/KSME-B.1918.104.22.1686
The effects of porous wind fence on the pressure characteristics around a 2-dimensional prism model of triangular cross-section were investigated experimentally. The fence and prism model were embedded in a neutral atmospheric surface boundary layer over the city suburb. In this study, various fences of different porosity, back fence, inclination angle of prism and location of additional back prisms were tested to investigate their effects on the pressure and wall shear stress of the prism surface. The fence and prism had the same height of 40 mm and Reynolds number based on the model height was Re=3.9*10
. The porous fence with porosity 40% was found to be the best wind fence for decreasing the mean and pressure fluctuations on the prism surface. By installing the fence of porosity 40%, the wall shear stress on the windward surface of prism was largely decreased up to 1/3 of that without the fence. This indicates that the porous fence is most effective to abate the wind erosion. Pressure fluctuations on the model surface were decreased more than half when a back fence was located behind the prism in addition to the front fence. With locating several back prisms and decreasing the inclination angle of triangular prism, the pressure fluctuations on the model surface were increased on the contrary.
Numerical analysis of particle behavior around a bipolar charged electret fiber
An, Gang-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1509~1517
DOI : 10.22634/KSME-B.1922.214.171.1249
Charged and uncharged particle motions and collection characteristics around a bipolar charged rectangular shape electret fiber are studied numerically. Particle inertia, fluid drag, Coulomb force and polarization force are considered to predict the particle motion around the electret fiber. The effects of particle sizes, flow velocities, number of charges and polarities are also systematically investigated. For small size particles, the single fiber collection efficiency is greatly dependent on the charge polarity and the number of charges on a particle. However, particles larger than 5.mu.m do not show charging effect on collection efficiencies in the flow velocity ranges from 1.5 cm/s to 150 cm/s when the maximum charges are within +5 to -10. The results show that a strong electric field gradient at the corner of the bipolar charged fiber plays a very important role on collecting particles regardless of its charge polarity because of the polarization force. It also shows that the most penetrating particle size for a single electret fiber decreases as the flow velocity increases and the number of charges of a particle decreases.
Numerical calculation of the dynamic properties of Weis-Fogh type ship's propulsion mechanism
No, Gi-Deok ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1518~1526
DOI : 10.22634/KSME-B.19126.96.36.1998
The dynamic properties of a ship's propulsion mechanism of Weis-Fogh type are studied by the discrete vortex method. The wing in the channel is approximated by a finite number of bound vortices and free vortices representing the separated flow are introduced from the trailing edge of the wing. The time histories of the thrust, the drag, and the moment acting on the wing are calculated, including the unsteady force due to the change of strength of the bound vortices. These calculated results show a similar tendency to the experimental ones qualitatively and the dynamic properties of this propulsion mechanism are numerically clarified.
Numerical study on extinction and acoustic response of diluted hydrogen-air diffusion flames with detailed and reduced chemistry
Son, Chae-Hun ; Jeong, Seok-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1527~1537
DOI : 10.22634/KSME-B.19188.8.131.527
Extinction characteristics and acoustic response of hydrogen-air diffusion flames at various pressures are numerically studied by employing counterflow diffusion flame as a model flamelet in turbulent flames in combustion chambers. The numerical results show that extinction strain rate increases linearly with pressure and then decreases, and increases again at high pressures. Thus, flames are classified into three pressure regimes. Such nonmonotonic behavior is caused by the change in chemical kinetic behavior as pressure rises. The investigation of acoustic-pressure response in each regime, for better understanding of combustion instability, shows different characteristics depending on pressure. At low pressures, pressure-rise causes the increase in flame temperature and chain branching/recombination reaction rates, resulting in increased heat release. Therefore, amplification in pressure oscillation is predicted. Similar phenomena are predicted at high pressures. At moderate pressures, weak amplification is predicted since flame temperature and chain branching reaction rate decreases as pressure rises. This acoustic response can be predicted properly only with detailed chemistry or proper reduced chemistry.
Kinetic energy conservative algorithm in moving grid system using segregated finite element formulation
Seong, Jae-Yong ; Choe, Hyeong-Gwon ; Yoo, Jung-Yul ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1538~1551
DOI : 10.22634/KSME-B.19184.108.40.2068
Kinetic energy conservation for fixed and moving grids is examined in time-accurate finite element computation of fully unsteady inviscid flows. As numerical algorithms, fractional step method (FSM) and modified SIMPLE are used. To simulate the flow in moving grid system, arbitrary Lagrangian-Eulerian (ALE) method is adopted. In the present study, the energy conserving time integration rule for finite element algorithm is proposed and discussed schematically. It is shown that the discretization by Crank-Nicolson in time and Galerkin (central difference) in space must be used to ensure energy conservation. The developed code has been tested for a standing vortex in fixed or moving grid system, sloshing in a tank and propagation of a solitary wave, and has been shown to be a completely energy conserving algorithm.
Analysis of ice-formation phenomena for fully developed laminar water flow in concentric circular-tube annuli
Seo, Jeong-Se ; No, Seung-Tak ;
Transactions of the Korean Society of Mechanical Engineers B, volume 21, issue 11, 1997, Pages 1552~1561
DOI : 10.22634/KSME-B.19220.127.116.112
In this numerical study, it is investigated for the ice-formation phenomena for water flow in a concentric tube. The freezing layers of ice in both the inner and outer wall of a concentric tube are simultaneously considered. In the solution strategy, the complete set of governing equations in both the solid and liquid regions are resolved. Numerical results are obtained by varying the inner/outer wall temperatures and Reynolds number. The results show that the inner/outer wall temperatures have the great effect on the thickness of the solidification layer thereof. The shapes of ice layer in both the inner and outer wall can be expressed as a function of inverse Graetz number. As the wall temperature in inner or outer tube decreases, the heat transfer coefficients in both inner and outer ice layer surfaces increase absolutely.