Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
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 24, Issue 12 - Dec 2000
Volume 24, Issue 11 - Nov 2000
Volume 24, Issue 10 - Oct 2000
Volume 24, Issue 9 - Sep 2000
Volume 24, Issue 8 - Aug 2000
Volume 24, Issue 7 - Jul 2000
Volume 24, Issue 6 - Jun 2000
Volume 24, Issue 5 - May 2000
Volume 24, Issue 4 - Apr 2000
Volume 24, Issue 3 - Mar 2000
Volume 24, Issue 2 - Feb 2000
Volume 24, Issue 1 - Jan 2000
Selecting the target year
A Numerical Analysis and Experiment for Micro-Fans
Cho, Jin-Soo ; Pyun, Tae-Kyoon ; Park, Wang-Sik ; Chun, Chang-Kun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 895~906
DOI : 10.22634/KSME-B.2000.24.7.895
A three dimensional linear frequency-domain lifting surface panel method was used for the aerodynamic analysis of axial flow type micro-fans. As proven by the duct modeling, the tip clearance of the micro-fans tested is large enough to ignore the calculated effect of the duct system. As the numerical results and experimental data agreed well in the operating point region, the method was applicable in the parametric studies to determine the design parameters of axial flow fans. Experiments on micro-fans were carried out based on KS B 6311. The newly designed micro-fan showed improvements in both static pressure rise and volumetric flow rate compared to the existing fans at a given operating condition. No detection of surging and the smooth characteristic curve proved the improvement in performance. To reduce the fan noise in the fan design, it was necessary to make use of the frequency spectrum analysis data. Measurement of sound pressure level for micro-fans was conducted based on KS B 6361 and KS A 0705. The peak - which occurs at blade passage frequency and its higher harmonics due to the fan noise - was not detected. This justifies the design methodology of the blade.
Application of the Krylov Subspace Method to the Incompressible Navier-Stokes Equations
Maeng, Joo-Sung ; Choi, IL-Kon ; Lim, Youn-Woo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 907~915
DOI : 10.22634/KSME-B.2000.24.7.907
The preconditioned Krylov subspace methods were applied to the incompressible Navier-Stoke's equations for convergence acceleration. Three of the Krylov subspace methods combined with the five of the preconditioners were tested to solve the lid-driven cavity flow problem. The MILU preconditioned CG method showed very fast and stable convergency. The combination of GMRES/MILU-CG solver for momentum and pressure correction equations was found less dependency on the number of the grid points among them. A guide line for stopping inner iterations for each equation is offered.
Numerical Analysis of Three-Dimensional Flow in a Forward Curved Centrifugal Fan
Yoon, Joon-Yong ; Maeng, Joo-Sung ; Byun, Sung-Joon ; Lee, Sang-Hwan ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 916~923
DOI : 10.22634/KSME-B.2000.24.7.916
Numerical study of three-dimensional turbulent flow in a forward curved centrifugal fan is presented. Standard
turbulence model and non-orthogonal curvilinear coordinates arc used to consider the turbulent flow field and complex geometry. Finite Volume approach is adopted for discretization scheme and structured grid system is used to help convergence. Multiblock grid system is used for flow field and divided into five domains that are inlet, outlet, impeller, tip clearance and scroll. It is assumed that the flow field is steady and incompressible. These numerical results are compared with the experimental data inside a rotor and at the fan outlet. Most important flow features are captured through this numerical approach. Finally details of flow field inside a fan are described and analyzed.
Mean Flow Velocity Measurement Using the Sound Field Reconstruction
Kim, Kun-Soon ; Cheung, Wan-Sup ; Kwon, Hyu-Sang ; Park, Kyung-Am ; Paik, Jong-Seung ; Yoo, Seong-Yeon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 924~929
DOI : 10.22634/KSME-B.2000.24.7.924
This paper addresses a new technique of measuring the mean flow velocity over the cross sectional area of the pipe using sound field reconstruction. When fluid flows in the pipe and two plane waves propagate oppositely through the medium, the flow velocity causes the change of wave number of the plane waves. The wave number of the positive going plane wave decreases and that of negative going one increases in comparison to static medium in the pipe. Theoretical backgrounds of this method are introduced in detail and the measurement of mean flow velocity using the sound field reconstruction is not affected by velocity profile upstream of microphones.
Effects of Tube Diameter on Nucleate Pool Boiling Heat Transfer
Kang, Myeong-Gie ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 930~937
DOI : 10.22634/KSME-B.2000.24.7.930
A series of data sets for the heat transfer coefficient versus wall superheat has been obtained experimentally using various combinations of tube diameters (
), surface roughness (
), and tube orientations (horizontal and vertical) to obtain effects of tube diameters on nucleate pool boiling heat transfer for the saturated water at atmospheric pressure. In addition, the results are compared with the well known Cornwell and Houston's correlation for horizontal tubes to identify the deviation of the present experimental data from the correlation and the applicability of it to vertical tubes. The experimental results show that the heat transfer coefficient decreases as the tube diameter increases for both horizontal and vertical tubes and they are in good agreement with the Cornwell and Houston's correlation within
Influence of Refrigeration Oil on Evaporation Heat Transfer Characteristics of R-290 Inside Micro Fin Tube
Park, Cheol-Min ; An, Young-Tae ; Lee, Wook-Hyun ; Kim, Jeung-Hoon ; Kim, Jong-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 938~944
DOI : 10.22634/KSME-B.2000.24.7.938
Recently, micro fin tube is widely used to heat exchanger for high performance. And, as the alternative refrigerants for R-22, hydrocarbons such as R-290, R-600 and R-600a are very promising because of their low GWP and ODP. Thus, R-290 was used as working fluid in this study. Most design of heat exchanger had been based on heat transfer characteristics of pure refrigerant although refrigerant oil exists in the refrigeration cycles. So, the influence of oil on heat transfer characteristics have to be considered for investigating exact evaporation heat transfer characteristics. But, this is an unresolved problem of refrigeration heat transfer. Therefore the influence of the refrigeration oil to the evaporation heat transfer characteristics of R-290 were conducted in a horizontal micro tin tube. The mineral oil was used as refrigeration oil. The experimental apparatus consisted of a basic refrigeration cycle and a system for oil concentration measurement. Test conditions are as the follows; evaporation temperature
, mass velocity 100
, heat flux 10
, oil concentration 0, 1.3, 3.3, 5.7 wt.%, and quality
. When refrigeration oil was entered, oil foaming was observed at the low quality region. And, very small bubbles were observed as quality was increased. Pressure drop and heat transfer coefficient increased as the concentration of refrigeration oil increased to 5 wt.%.. The performance index of heat exchanger was the highest near 3.3 wt.%.
Experimental Study on Flow Noise Generated by Axisymmetric Boundary Layer ( I ) - Wall Pressure Fluctuations on Axisymmetric Noses and on a Cylinder in an Axial Flow -
Lee, Seung-Bae ; Kim, Hooi-Joong ; Kwon, O-Sup ; Lee, Sang-Kwon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 945~956
DOI : 10.22634/KSME-B.2000.24.7.945
The axisymmetric bodies considered in this study have hemispherical and ellipsoidal noses. The near-field pressure fluctuations over each nose model at
were investigated in the laminar separation region and developing turbulent boundary layers using a 1/8' pin-holed microphone sensor. The wall pressure fluctuations were also measured in an axisymmetric boundary layer on a cylinder parallel to mean flow at a momentum thickness Reynolds number of 850 and a boundary layer thickness to cylinder radius ratio of 1.88.
Discharge Characteristics of Rotating Orifices with Length-to-Diameter Ratios and Inlet Corner Radii
Ha, Kyoung-Pyo ; Kang, Se-Won ; Kauh, Sang-Ken ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 957~966
DOI : 10.22634/KSME-B.2000.24.7.957
The effect of rotation on the discharge coefficient of orifices with various length-to-diameter ratios and two different inlet corner radii was studied. Length-to-diameter ratios of the orifices range from 0.2 to 10, while the inlet shapes are square edged, or round edges of radius-to-diameter ratio of 0.5. From the experiment, we found that rotational discharge coefficient and Rotation number, when based on ideal exit velocity of the orifice considering momentum transfer from the rotor, describe the effect of rotation very well. In this study, the discharge coefficients of rotating orifices are shown to behave similar to those of the well-known non-rotating orifices. For both rotating and non-rotating orifices, the discharge coefficients increase with the length-to-diameter ratio until a maximum is reached. The flow reattachments in the relatively short orifices are responsible for the increase. The coefficient then decreases with the length-to-diameter ratio due to the friction loss along the orifice bore. The length-to-diameter ratio that yields maximum discharge coefficient, however, increases with the Rotation number because the increased flow-approaching angle requires larger length-to-diameter ratio for complete reattachment. The length-to-diameter ratio for complete reattachment is shorter for round edged orifices than that of square edged orifices by about a unit length-to-diameter ratio.
Analysis of Transient Characteristics of a Steam Power Plant System
Park, Keun-Han ; Kim, Tong-Seop ; Ro, Sung-Tack ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 967~975
DOI : 10.22634/KSME-B.2000.24.7.967
Transient characteristics of a boiler and turbine system for a steam power plant are simulated. One-dimensional unsteady models are introduced for each component. An interaction between boiler and turbine and a control of the water level in the drum are taken into account. Transient responses of the system to the variations of main system variables such as fuel and air flow rate, cooling water injection rate at the attemperator, gas recirculation rate at the furnace and opening of the turbine control valve are examined. Effect of fluid inertia and tube wall thermal inertia on predicted dynamic behavior is investigated.
Interaction between Turbulent Boundary Layer and Wake Behind an Elliptic Cylinder at Incidence
Choi, Jae-Ho ; Lee, Sang-Joon ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 976~983
DOI : 10.22634/KSME-B.2000.24.7.976
The flow characteristics around an elliptic cylinder with axis ratio of AR=2 located near a flat plate were investigated experimentally to study the interaction between the cylinder wake and the turbulent boundary layer. The pressure distributions on the cylinder surface and on the flat plate were measured with varying the angle of attack of the cylinder. In addition, the velocity profiles of wake behind the cylinder were measured using a hot-wire anemometry As the angle of attack increases, the location of peak pressure on the windward and leeward surfaces of the cylinder moves toward the rear and front of the cylinder, respectively. At positive angles of attack, the position of the minimum pressure on the flat plate surface is moved downstream, but it is moved upstream at negative angles of attack. With increasing the angle of attack, the vortex shedding frequency is gradually decreased and the critical angle of attack exists in terms of the gap ratio. By installing the elliptic cylinder at negative angle of attack, the turbulent boundary layer over the flat plate is disturbed more than that at positive incidence. This may be attributed to the shift of separation point on the lower surface of the cylinder due to the presence of a ground plate nearby.
Characterization of Soot Particles Generated in Non-sooting and Sooting Normal Diffusion Flames
Choi, In-Chul ; Lee, Jae-Bok ; Hwang, Jung-Ho ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 984~993
DOI : 10.22634/KSME-B.2000.24.7.984
Characteristics of carbon soot particles generated in diffusion flames were studied. Non-sooting and sooting normal diffusion flames using propane or ethylene as fuel were selected. In the flames, soot volume fraction was measured by a thermocouple, and primary particle diameter and cluster size were analyzed by TEM photographs. The characteristics of soot particles depended on flame(non-sooting or sooting) and fuel(propane or ethylene) type. Unlike the sooting diffusion flames, particle growth and oxidation processes were clearly observed in the non-sooting diffusion flames. In the sooting diffusion flames, soot particle size was slightly changed at the flame tip.
Analysis of Dynamic Behavior of a Heat Recovery Steam Generator and Steam Turbine System
Park, Hyung-Joon ; Kim, Tong-Seop ; Ro, Sung-Tack ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 994~1001
DOI : 10.22634/KSME-B.2000.24.7.994
The dynamic behavior of a single-pressure heat recovery steam generator and turbine system for the combined cycle power plant is simulated on the basis of one-dimensional unsteady governing equations. A water level control and a turbine power control are also included in the calculation routine. Transient response of the system to the variation of gas turbine exit condition is simulated and effect of the turbine power control on the system response is examined. In addition, the effect of the treatment of inertia terms(fluid inertia and thermal inertia of heat exchanger metal) on the simulated transient response is investigated.
Reentrainment of Carbon Soot Particles in a Corona Discharge Reactor
Lee, Jae-Bok ; Hwang, Jung-Ho ; Bae, Gwi-Nam ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 1002~1009
DOI : 10.22634/KSME-B.2000.24.7.1002
Among the various types of diesel after-treatment device, the corona discharge reactor may be considered as a powerful process for trapping submicron particles. But after precipitation on the electrodes occurs, the reentrainment of particles is severe and often causes low or negative precipitation efficiency. Experiments were performed to investigate the effect of an applied voltage on the reentrainment of soot particles from the electrodes. A co-annular laminar diffusion flame burner was used as the soot generator. When a highly negative voltage was applied, exfoliation of the deposited soot particles and an increase in concentration of particles smaller than approximately 150 nm were observed. Turbulence induced from the negative tuft corona and sputtering caused particle reentrainment from the corona wire and from plates as well. Under soot laden combustion gas, a streamer corona often occurred in the wire-cylinder reactor. Because of its transient nature, streamer corona violently increased the concentration of reentrained particles and CO gas.
Modeling of Spray-Wall Interactions Considering Liquid Film Formation
Lee, Seong-Hyuk ; Ryou, Hong-Sun ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 1010~1019
DOI : 10.22634/KSME-B.2000.24.7.1010
The main purpose of this article is to propose and assess a new spray impingement model considering film formation, which is capable of describing the droplet distribution and film flows in direct injection diesel engines. The spray-wall interaction model includes several mathematical formulae, newly made by the energy conservation law and some experimental results. The model consists of three representative regimes, rebound, deposition and splash. In addition, the film flow is described in the present model by solving the continuity and momentum equations for film flows using the integral method. To assess the new spray impingement model, the calculated results using the new model are compared with several experimental data for the normally impinging diesel sprays. The film model is also validated through comparing film radius and thickness against experimental data. The results show that the new model is generally in better agreement with experimental data and acceptable for prediction of the film radius and thickness.
A New Model for the Analysis of Non-Spherical Particle Growth
Jeong, Jae-In ; Choi, Man-Soo ;
Transactions of the Korean Society of Mechanical Engineers B, volume 24, issue 7, 2000, Pages 1020~1027
DOI : 10.22634/KSME-B.2000.24.7.1020
A simple model for describing the non-spherical particle growth phenomena has been developed. In this model, we solve simultaneously particle volume and surface area conservation sectional equations that consider particles' non-sphericity. From the correlation between two conserved properties of sections, we can predict the evolution of the aggregates' morphology. This model was compared with a simple monodisperse-assumed model and more rigorous two-dimensional sectional model. For comparison, formation and growth of silica particles have been simulated in a constant temperature reactor environment. This new model showed good agreement with the detailed two-dimensional sectional model in total number concentration and primary particle size. The present model successfully predicted particle size distribution and morphology without costing very heavy computation load and memory needed for the analysis of two dimensional aerosol dynamics.