• Title/Summary/Keyword: Temperature Profile

Search Result 1,255, Processing Time 0.027 seconds

Comparison of the Temperature Profile with the Backscattering Strength by the ADCP Data in the Southwestern Part of the East Sea (동해 남서해역에서 ADCP 자료에 의한 후방산란 강도와 수온구조와의 비교)

  • 강돈혁;나정열
    • 한국해양학회지
    • /
    • v.29 no.3
    • /
    • pp.287-295
    • /
    • 1994
  • The relationship between temperature profile and backscattering strength(S/SUB y/) computed by the ADCP data is studied in warm eddy of the southwestern parts of the East Sea of Korea in April, 1993. The result shows that S/SUB y/ with depth in N-S direction shows a symmetric shape that is almost the same as the warm eddy. But the profile of S/SUB y/ with depth in N-S direction shows a symmetric shape that is almost the same as the warm eddy. But the profile of S/SUB y/ in E-W direction shows asymmetric shape where the S/SUB y/ of the eastern parts is smaller than that of western parts. The asymmetric distribution may be due to the migration of a large number of scatterer(mainly zooplankton) carried by EKWC(East Korea Warm Current). Profile of the S/SUB y/ is similar to the temperature with depth in the ADCP data of CREAMS 93(Circulation Research of the East Asian Marginal Seas).

  • PDF

Effects of die cooling on change of extrusion characteristics of Al-Mn-based thin-walled flat multi-port tube (금형 냉각이 Al-Mn계 다중압출 평판관의 압출 특성 변화에 미치는 영향)

  • Young-Chul Shin;Seong-Ho Ha;Tae-Hoon Kang;Kee-Ahn Lee;Seung-Chul Lee
    • Design & Manufacturing
    • /
    • v.17 no.4
    • /
    • pp.63-71
    • /
    • 2023
  • In order to increase the extrusion production speed of aluminum, extrusion die cooling technology using liquid nitrogen has recently attracted a lot of attention. Increasing the extrusion speed increases the temperature of the bearing area of extrusion dies and the extrusion profile, which may cause defects on the surface of extruded profile. Extrusion die cooling technology is to directly inject liquid nitrogen through a cooling channel formed between the die and the backer inside the die-set. The liquid nitrogen removes heat from the die-set, and gaseous nitrogen at the exit of the channel, covers the extrusion profile of an inert atmosphere reducing the oxidation and the profile temperature. The aim of this study is to evaluate the cooling capacity by applying die cooling to extrusion of Al-Mn-based aluminum alloy flat tubes, and to investigate the effects of die cooling on the change in extrusion characteristics of flat tubes. Cooling capacity was confirmed by observing the temperature change of the extrusion profile depending on whether or not die cooling is applied. To observe changes in material characteristics due to die cooling, surface observation is conducted and microstructure and precipitate analysis are performed by FE-SEM on the surface and longitudinal cross section of the extruded flat tubes.

A Numerical Analysis of the Characteristics with High Temperature Air Combustion in Counterflow Diffusion Flame (대향류 확산화염의 고온공기 연소특성에 관한 수치해석)

  • Cho, Eun Seong;Kobayashi, Hideaki;Chung, Suk Ho
    • Journal of the Korean Society of Combustion
    • /
    • v.8 no.4
    • /
    • pp.9-14
    • /
    • 2003
  • High temperature air combustion technology has been utilized by using preheated air over 1100 K and excessive exhaust gas recirculation. Numerical analysis was performed to investigate the combustion characteristics with high temperature deficient oxygen air combustion by adopting a counterflow as a model problem accounting for detailed chemical kinetics. Methane($CH_4$) was used as a test fuel and calculated oxidizer conditions were low temperature high oxygen (300K, $X_{O2}=0.21$) and high temperature low oxygen (1300K, $X_{O2}=0.04$) conditions. The latter case showed that the flame temperature is lower than the former case and its profile showed monotonic decrease from oxidizer to fuel side, without having local maximum flame temperature at high stretch rate. Also, heat release rate was one order lower and it has one peak profile because of low oxygen concentration and heat release rate integral is almost same for stretch rate. High temperature low oxygen air combustion shows low NO emission characteristics.

  • PDF

The Geometric Error Analysis by Various Various Inputs In Surface Grinding (평면연삭에서 다변수 입력에 의한 형상오차 해석)

  • 김강석;홍순익;송지복
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1997.04a
    • /
    • pp.868-872
    • /
    • 1997
  • The thermal deformation of a workpiece during grinding is one of the most important factors that affect a flatness of a grinding surface. The heat generated in one-pass surface grinding causes the convex deformation of a workpiece. Therefore, the ground surface represents a conacve profile. In the analysis a simple model of the temperature distribution,based on the result of a finite element method, is applied. The analyzed results are compared with experimental results in surface grinding. The main results obtained are as follows; (1) The temperature distibution of a workpiece by FEM is comparatively in good agreement with the experimental results. (2) The bending moment by generated heat cause a convex deformation of the workpiece and it reads to a concave profile of the grinding surface.

  • PDF

The Precise Extrusion-Technical Development to Get Excellent Mechanical-property and Accurate Shape- Dimension (우수한 기계적 특성과 형상치수 확보를 위한 정밀 압출기술개발)

  • Lee, Hyun-Cheol;Lee, Kwang-Sik;Oh, Kae-Hee;Park, Sang-Woo
    • Proceedings of the KSR Conference
    • /
    • 2009.05b
    • /
    • pp.311-320
    • /
    • 2009
  • Most advanced countries are researching to apply light weight materials far rolling stock because weight reduction for railway body derives cost-saving, energy-saving, and high-speed. Likewise, current Korea rolling stock field makes arduous effects of weight-reduction, miniaturization, and high-efficiency to achieve a high-speed railway. Aluminum becomes suitable material for these projects because it is much lighter than steel or stainless. Manufacturing the railway car body by using the Aluminum is increasing because Aluminum is not bringing the corrosion by unique oxidation-passivate. Aluminum extrusion profile far railway body requires a high mechanical property, accurate shape dimension, and stable quality because the railway body is composed with many different kinds of extruded profiles. Therefore, it is necessary to research about Aluminum precision-extrusion technology to maintain exit temperature and die load. The goal of this project is applying the Aluminum extrusion profile to next-generation railway car body by developing the Aluminum extrusion profile according to precision-extrusion technology which may maintain isothermal exit temperature.

  • PDF

Performance Prediction of 3 MWth Chemical Looping Combustion System with Change of Operating Variables (3 MWth 급 매체순환연소 시스템의 운전변수 변화에 따른 성능 예측)

  • RYU, HO-JUNG;NAM, HYUNGSEOK;HWANG, BYUNG WOOK;KIM, HANA;WON, YOOSEOB;KIM, DAEWOOK;KIM, DONG-WON;LEE, GYU-HWA;CHOUN, MYOUNGHOON;BAEK, JEOM-IN
    • Journal of Hydrogen and New Energy
    • /
    • v.33 no.4
    • /
    • pp.419-429
    • /
    • 2022
  • Effects of operating variables on temperature profile and performance of 3 MWth chemical looping combustion system were estimated by mass and energy balance analysis based on configuration and dimension of the system determined by design tool. Air reactor gas velocity, fuel reactor gas velocity, solid circulation rate, and solid input percentage to fluidized bed heat exchanger were considered as representative operating variables. Overall heat output and oxygen concentration in the exhaust gas from the air reactor increased but temperature difference decreased as air reactor gas velocity increased. Overall heat output, required solid circulation rate, and temperature difference increased as fuel reactor gas velocity increased. However, overall heat output and temperature difference decreased as solid circulation rate increased. Temperature difference decreased as solid circulation rate through the fluidized bed heat exchanger increased. Effect of each variables on temperature profile and performance can be determined and these results will be helpful to determine operating range of each variable.

Springback for the Warm 2D Draw-bending of Steel Sheets (박판의 온간 2차원 드로오 벤딩에서의 스프링백)

  • Lee S. M.;Chang S. H.;Choi Y. C.;Heo Y. M.;Seo D. G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2001.10a
    • /
    • pp.75-80
    • /
    • 2001
  • The purpose of this study is to investigate the characteristics of springback for various process conditions of the 2D draw-bending operation. The process variables are the forming temperature, the geometry of tools such as punch profile radius(Rp) and die profile radius(Rd). Especially, in order to control the springback, the use of the warm forming method is applied. For the warm draw-bending, five steps of temperature ranges, from room temperature to $200^{\circ}C$, were adopted. And two kinds of steel sheets, namely SCP1 and TRIP(transformation-induced plasticity), the newly developed high strength Steel, were adopted. As a result, the springback was affected by the elevated temperature and the geometry of tools in two kinds of steel sheets.

  • PDF

Finite Element Analysis of Heat and Moisture Transfer in Porous Materials (다공성 물질의 열 및 습도 전달에 관한 유한요소 해석)

  • Lee, Ho-Rim;Geum, Yeong-Tak;Song, Chang-Seop;O, Geun-Ho
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.16 no.7
    • /
    • pp.158-167
    • /
    • 1999
  • Heat and moisture transfer associated with porous materials are investigated. The heat and moisture transfer in porous materials caused by the interaction of moisture gradient, temperature gradient, conduction, and evaporation are considered. The variations of temperature and moisture not only change the volume but also induce the hygro-thermal stress. The finite element formulation for solving the temperature and moisture transfer as well as the associated hygro-thermal stresses is developed. In order to verify the finite element formulation, the heat and moisture moving boundary problem in a half space and the hygro-thermo-mechanical problem in an infinite plate with a circular hole are analyzed. Temperature profile, moisture profile, and hygro-thermal stresses are compared with those of analytic solution and other investigator. Good agreements are examined

  • PDF

Line-profile Formula in the Carbon Nanotubes by Electron Spin Resonance

  • Park, Jung-Il;Lee, Haeng-Ki
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.16 no.1
    • /
    • pp.11-21
    • /
    • 2012
  • The line-width of carbon nanotubes (CNTs) was studied as a function of the temperature at a frequency of 9.49 GHz in the presence of external electromagnetic radiation. The relative frequency dependence of the absorption power is obtained with the projection operator technique (POT) proposed by Kawabata. The line-width increased as the temperature increased in the high-temperature region (T>200 K). The scattering is little affected in the low-temperature region (T<200 K) because there is no correlation between the resonance field and the Fermi-Dirac distribution function. Thus, the present technique is considered to be more convenient to explain the resonant system as in the case of other optical transition problems.

A Numerical Analysis of the Thermal Hydraulic Characteristics in a Channel of 37 Rods (전산해석을 통한 37개봉으로 구성된 유로에서의 열유체학적 특성분석)

  • 전태현;심윤섭
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.10 no.1
    • /
    • pp.50-55
    • /
    • 1986
  • Characteristics of the flow and heat transfer in a channel of 37 rods are investigated numerically. The flow is taken to be a fully developed incompressible laminar flow and it has an uniform temperature profile at the inlet and flows down through the channel of constant wall temperature. A boundary-fitted coordinate system is used for the complex geometry. Calculation is initiated by calculating the developed flow profile and then proceeds to temperature development. Through the calculation the details of the flow and temperature distribution characteristics are found, and discussion is made on the mechanism of the transport phenomena in the complex geometry in terms of wall shear stress distribution, non-dimensionalized velocity, friction factor, Nusselt number distribution, Reynolds number, and porosity. Also the effects of the eccentricity in rod configuration are analyzed and its importance is emphasized.