• Title/Summary/Keyword: Dimensional Variations

Search Result 632, Processing Time 0.033 seconds

A Study on the hydraulic hinge for automobile trunk door (자동차용 유압식 트렁크 힌지에 관한 연구)

  • Huh Y.;Choi C.H.;Kim H.I.;Seok C.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2006.05a
    • /
    • pp.427-428
    • /
    • 2006
  • In this study, three dimensional(3-D) orifice model was developed fur automobile trunk hinge. Using that model the flow analysis was conducted to estimate pressure tendency of orifice model according to the variations in the design factors such as oil viscosity and orifice size.

  • PDF

The Effects of Thermosolutal Convection on Macrosegregation during Alloy Solidification (합금응고과정에서 이중확산대류가 거시편석에 미치는 영향)

  • Lee, Gyun-Ho;Mok, Jin-Ho;Lee, Jin-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.25 no.10
    • /
    • pp.1337-1345
    • /
    • 2001
  • Numerical investigation is made to study the effects of thermosolutal convection on the formation of macrosegregation in a Pb-Sn alloy solidification process in a two dimensional confined rectangluar mold. The basic equations are sovled using the Contrinum Model theory with the SIMPE algorithm during the solidification process. In addition, to track the liquid-solid interface with time variations, the moving boundary condition was adopted and moving irregular interface shapes were treated with the time-dependent, boundary-fitted coordinate system. As the temperature reduces from the liquidus to the solidus, the liquid concentration of Sn, the lighter constituent, increases. Then the buoyancy-driven flow due to temperature and liquid composition gradients occurs in the mushy region and forms the complicated macrosegregation maps. belated to this phenomena, effects on the macrosegregation formation depending on the cooling condition and gravity values are examined.

An Analysis of Engine Cooling using a Three-dimensional Radiator Model (3차원 방열기 모델을 이용한 엔진냉각 해석)

  • 이영림
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.9 no.4
    • /
    • pp.10-17
    • /
    • 2001
  • The performance of a radiator is generally determined using a wind tunnel, in which the air velocity is uniform. However, when it is installed in a car, the distribution of the air velocity becomes nonuniform due to front-end openings, cross members, and horns etc., resulting in lower performance. In this study, several underhood flow simulations have been first performed to get flow rates and velocity distributions over the radiator. Secondly heat release rates are calculated by both a performance curve and a radiator model. Finally, using an engine cooling system simulator, radiator-top-tank temperature is predicted and the variations of heat release rate and radiator-top-tank temperature with nonuniformity of air velocity distributions are analyzed. The results show that the current engine cooling model successfully accounts for the nonuniformity effects that should be considered for higher accuracy in predicting engine cooling performance.

  • PDF

Analysis of Stress Singularities on Interfaces of Friction Welded Dissimilar Materials (마찰용접에 의한 이종재 접합계면에 대한 응력특이성의 해석)

  • Chung, Nam-Yong;Park, Chul-Hee
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.13 no.2
    • /
    • pp.142-148
    • /
    • 2005
  • In this paper, the stress singularity on interface of friction welded dissimilar materials was investigated by using 2-dimensional elastic boundary element method. It is required that stress distributions and stress singularities on an interface for friction welded dissimilar materials analize to establish strength evaluation. The stress singularity index ($\lambda$) and stress singularity factor ($\Gamma$) were calculated from the results of stress analysis. The stress singularities on variations for shapes and thickness of friction welded flashes were analized and discussed. This paper suggested that the strength evalution by using the stress singularity factors as fracture parameters, considering the stress singularity on an interface edge of friction welded dissimilar materials were very useful.

Characteristic of Frost Growth on a Cold Cylinder Surface in Cross Flow (직교류 내 원관 표면에서의 서리층 성장 특성)

  • Yang Dong-Keun;Kim Min-Soo;Lee Kwan-Soo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.18 no.2
    • /
    • pp.122-128
    • /
    • 2006
  • In this paper, frosting experiments were conducted with variations of frosting parameters in order to obtain the correlations of frost properties. As a result, the local thickness, density, and surface temperature of the frost layer were presented. The dimensionless correlations for the frost thickness, frost density, frost surface temperature and heat transfer coefficient were derived as functions of dimensionless frosting parameters by using a dimensional analysis.

A Numerical Study of the Heat Transfer Characteristics in a Printed Circuit Board (PCB내의 열전달특성에 관한 수치적 연구)

  • Pak, H.Y.;Park, K.W.;Lee, J.H.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.7 no.3
    • /
    • pp.461-472
    • /
    • 1995
  • The interaction of laminar mixed convection and surface radiation in a two-dimensional channel with an array of rectangular blocks is analyzed numerically. Three blocks are maintained at high temperature and the other bottom and top horizontal walls are insulated. Discrete ordinate method(DOM) is introduced to analyze the radiative heat transfer. The effects of the variations of Reynolds number and channel specifications on the heat transfer characteristics are investigated. The average Nusselt numbers along the block surfaces are correlated and presented in terms of Reynolds number and dimensionless geometric parameters such as the block spacing, height and channel spacing. For the conditions considered in this study, average Nusselt numbers along the block surfaces are strongly influenced by the channel spacing and Reynolds number but weakly influenced by the block spacing and block height.

  • PDF

Borehole radar monitoring of infiltration processes in a vadose zone

  • Jang, Han-Nu-Ree;Park, Mi-Kyung;Kuroda, Seiichiro;Kim, Hee-Joon
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 2007.06a
    • /
    • pp.313-316
    • /
    • 2007
  • Ground-penetrating radar (GPR) is an effectiveness tool for imaging spatial distribution of hydrogeologic parameters. An artificial groundwater recharge test has been conducted in Nagaoka City in Japan, and time-lapse crosshole GPR data were collected to monitor infiltration processes in a vadose zone. Since radiowave velocities in a vadose zone are largely controlled by variations in water content, the increase in traveltimes is interpreted as an increase in saturation in the test zone. We use a finite-difference time-domain method in two-dimensional cylindrical coordinates to simulate field results. Numerical modeling successfully reproduces the major feature of velocity changes in the filtration process.

  • PDF

A Numerical Study on Combined Solution and Evaporation during Spin Coating Process (Wafer Spin Coating 공정에서 증발과 용액이 박막 형성에 미치는 영향에 관한 연구)

  • 노영미;임익태;김광선
    • Journal of the Semiconductor & Display Technology
    • /
    • v.2 no.1
    • /
    • pp.25-29
    • /
    • 2003
  • The fluid flow, mass transfer, heat transfer and film thickness variation during the spin coating process are numerically studied. The model is said to be I-dimensional because radial variations in film thickness, concentration and temperature are ignored. The finite difference method is employed to solve the equations that are simplified using the similarity transformation. In early time, the film thinning is due to the radial convective outflow. However that slows during the first seconds of spinning so the film thinning due to evaporation of solvent becomes sole. The time varing film thickness is analyzed according to the wafer spin speed, the various solvent fraction in the coating liquid, and the various solvent vapor fraction in the bulk of the overlying gas during the spin coating is estimated.

  • PDF

Performance Characteristics of Side Channel Type Regenerative Pumps (사이드채널형 재생펌프의 성능 특성에 관한 실험적 연구)

  • Kang Shin-Hyoung;Lim Hyung-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.29 no.3 s.234
    • /
    • pp.306-313
    • /
    • 2005
  • 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.

Prediction of combustion field in granular propellant with moving boundary (이동경계면을 갖는 연소실내에서의 입자상의 고체연료 연소장 예측)

  • 조한창;윤재건;신현동;김종욱
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.16 no.12
    • /
    • pp.2385-2394
    • /
    • 1992
  • Granular solid propellants having energy and fast burning rate produce great thrusts within extremely short time intervals. Thus numerical researchs prevailed rather than experimental. Using a 2-phase fluid dynamics model among 1-dimensional 2-phase models, a numerical program was set up to describe reacting flow fields, moving boundary with oscillating pressure waves and constitutive laws research. It deserves special emphasis that correlations of convective heat transfer coefficient and viscous drag force among constitutive laws are tested and discussed because slight variations of their constants make a large influence on their results. In this calculations, some of correlations make the large difference in results. Therefore constitutive laws for convective heat transfer coefficient and viscous drag force need more considerations with experiments.