• Title/Summary/Keyword: 사각곡관

Search Result 6, Processing Time 0.018 seconds

A Study on the Hot Metal Extrusion Bending Process for the Rectangular Curved Tube (사각단면 금속곡관 제품의 열간압출 굽힘가공에 관한 연구)

  • Park D. Y.;Youn S. H.;Jin I. T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2001.10a
    • /
    • pp.212-215
    • /
    • 2001
  • The bending process for the rectangular curved tube can be developed by the hot metal extrusion machine with the multiple punches moving in the different velocity. The bending phenomenon can be controlled by the two variables, the one of them is the difference of velocity at the die exit section by the different velocity of billets through the multi-hole container. The other is the difference by the different hole diameter. The results of the experiment show that the rectangular curved tube can be formed by the extrusion process and that the curvature of the curved product can be controlled by the velocity of punch and the diameter of container hole and that the defects such as the distortion of section and the thickness change of the wall of tube and the folding and wrinkling of thin tube did not happen after the bending processing by the extrusion bending machine.

  • PDF

Study on Methanol Conversion Efficiency of Steam-Methanol Reforming on Pipe Shape and Flow Rate Variation in Curved Channel (수증기-메탄올 개질기의 곡유로 채널형 관 형태 변화에 따른 메탄올 전환율 및 유동 특성에 관한 수치해석적 연구)

  • Seong, Hong Seok;Lee, Chung Ho;Suh, Jeong Se
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.40 no.3
    • /
    • pp.173-179
    • /
    • 2016
  • This is a numerical study on the curved channel type of hydrogen reformer using the commercial code of fluid dynamics. We numerically compared the numerical model in a previous study model and the modelling of a tube type curved channel. In the result of numerical analysis on 4 types of curved channel reformers, the methanol conversion efficiency of type 1~4 were 45.0%, 45.3%, 45.6%, 45.6% respectively, and there was hardly any difference by ${\pm}0.6%$. In light of flow characteristics, the rectangle type tube and the type 2 with $45^{\circ}$ turn showed most uniform flow characteristics and concentration distribution of methanol, and the circular type tube and the type 3 with $90^{\circ}$ turn had most un-uniform flow characteristics and concentration distribution of methanol. We concluded that the design for curved channel reformer has to have rectangle type tube with curve of almost $45^{\circ}$ as in the type of curved pipe with $45^{\circ}$ turn.

Three Dimmensional Turbulent Flow Analysis in a 90° Square Sectioned Duct with Strong Curvature (사각단면을 갖는 90° 급곡관의 3차원 난류유동 해석)

  • Maeng, J.S.;Lee, J.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.3 no.1
    • /
    • pp.11-25
    • /
    • 1991
  • The steady, incompressible developing 3-dimensional turblent flow in a square sectioned curved duct has been investigated by using partially-parabolic equation and Finite Analytic Method. The calculation of turbulent flow field is performed using 2-equation K-$\epsilon$ turbulence model, modified wall function, simpler algorithm and numerically generated body fitted coordinates. Iso-mean velocity contours at the various sections are compared with the existing experimental data and elliptic solutions by other authors. In the region of $0^{\circ}<{\theta}<71^{\circ}$, present results agree with the experimental data much better than the elliptic solution for the similar number of grid points. Furthermore, for the same tolerance, the present solution converges four times faster than the elliptic solution.

  • PDF

Analysis of Dispersion Characteristics of Circumferential Guided Waves and Application to feeder Cracking in Pressurized Heavy Water Reactor (원주 유도초음파의 분산 특성 해석 및 가압중수로 피더관 균열 탐지에의 응용)

  • Cheong, Yong-Moo;Kim, Sang-Soo;Lee, Dong-Hoon;Jung, Hyun-Kyu
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.24 no.4
    • /
    • pp.307-314
    • /
    • 2004
  • A circumferential guided wave method was developed to detect the axial crack on the bent feeder pipe. Dispersion curves of circumferential guided waves were calculated as a function of curvature of the pipe. In the case of thin plate, i.e. infinite curvature, as the frequency increases, the $S_0$ and $A_0$ mode coincide and eventually become Rayleigh wave mode. In the case of pipe, however, as the curvature increases, the lowest modes do not coincide even in the high frequencies. Based on the analysis, a rocking technique using angle beam transducer was applied to detect an axial defect in the bent region of PHWR feeder pipe. Based on the analysis of experimenal data for artificial notches, the vibration modes of each signal were identified. It was found that the notches with the depth of )0% of wall thickness can be detected with the method.

A Study on the Bending Process for the Circular Curved Tube and Rectangular Curved Tube with Fins (핀이 부착된 금속곡관 제품의 열간압출 굽힘가공에 관한 연구)

  • Kim M. G.;Park J. W.;Jin I. T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2001.10a
    • /
    • pp.204-207
    • /
    • 2001
  • The bending process for the circular curved tube and rectangular curved tube with fins can be developed by the hot metal extrusion machine with the multiple punches moving in the different velocity. The bending phenomenon can be controlled by the two variables. The one of them is the difference of velocity at the die exit section by the different velocity of billets through the multi-hole container. The other is the one by the different hole diameter. The results of the experiment show that the circular curved tube with fins and rectangular curved tube with pins can be formed by the extrusion process and that the curveture of the product can be controlled by the velocity of punch and diameter of container hole and that the defects such as the distortion of section and the thickness change of the wall of tube the folding and wrinkling of thin tube and fins did not happen after the bending processing by the extrusion bending machine.

  • PDF

Hot Metal Extru-Bending Process for Curved Aluminum Tube Products with Circular or Rectangular Sections (원형 또는 사각 단면을 가지는 알루미늄 곡관 튜브제품의 열간금속압출굽힘가공)

  • Park D. Y;Jin I. T
    • Transactions of Materials Processing
    • /
    • v.13 no.8
    • /
    • pp.663-670
    • /
    • 2004
  • The bending phenomenon has been known to be occurred by the difference of velocity at the die exit. The difference of velocity at the die exit section can be obtained by the different velocity of billets through the multi-hole container. The difference of velocity at the die exit can be controlled by the two variables, the one of them is the different velocity of extrusion punch through the multi-hole container, the other is the difference of hole diameter of muliti-hole container. In this paper the difference of hole diameter is applied. So it can bend during extruding products because of the different amount of two billets when billets would be bonded in the porthole dies cavity. And the bending curvature can be controlled by the size of holes. The experiments with aluminum material for the curved tube product had been done for circular or rectangular curved tube section. The results of the experiments show that the curved tube product can be formed by the extru-bending process without the defects such as distortion of section and thickness change of wall of tube and folding and wrinkling. The curvature of product can be controlled by shape of cross section and the difference of billet diameters. And it is known that the bonding and extruding and bending process can be done simultaneously in the die cavity by the experiments that rectangular hollow curved tubes could be extruded by porthole dies with four different size billets made of aluminum material. And it shows that bending phenomenon can happen during extruding with for different billets from the analysis by DEFORM-3D.