• 제목/요약/키워드: Disk shape

검색결과 353건 처리시간 0.026초

트윈롤 시스템을 이용한 천연가스 하이드레이트 펠릿의 연속성형 (Study on the Continuous Forming of Natural Gas Hydrate Pellet using Twin Roll System)

  • 이윤후;김흥수;고봉환;송명호
    • 한국기계가공학회지
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    • 제11권6호
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    • pp.152-157
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    • 2012
  • This study investigates compressive strength of ice pellet strip which is potential medium for Natural Gas Hydrate(NGH) extruded from die holes of Twin-roll Press for Continuous Pelletizing(TPCP). Recently, the prototype of TPCP is newly developed where ice powder is continuously fed and extruded into strip-type pellet between twin rolls. The system is specifically designed for future expansion towards mass-production of ice pellet strips or solid form of natural gas hydrate. It is shown that the compressive strength of pellet strip heavily depends on factors in extrusion process such as disk size, surface smoothness, ring size, taper shape, feeding mechanism, and rotational speed. Here, the mechanism of TPCP, along with compressive strength of pellets is discussed in terms of its feasibility for producing NGH pellets in the future.

펄스분리장치의 이중 슬릿형 파열판 매개변수 연구 (A Parametric Sturdy on Double Slit Type Rupture Disc of Pulse Separation Device)

  • 한혁섭;조원만;구송회;이방업
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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    • pp.105-112
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    • 2010
  • 이중 펄스 로켓 추진기관은 하나의 연소관 안에 특성이 다른 2개의 추진제가 격벽에 의해 2개의 공간에 분리되어 있는 고체 추진기관이다. 유한요소법을 이용한 탄소성 동적거동해석에 의하여 펄스분리장치 파열판의 파열해석을 수행하였다. 파열판의 슬릿 크기를 변경한 해석을 수행하여 파열형상, 파열시점을 해석함으로써 슬릿의 설계 변수가 파열판에 미치는 영향을 검토하였다. 해석 결과는 펄스분리장치 파열판 슬릿 크기의 변경을 통한 파열압력의 조절에 사용할 수 있다.

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정적 받음각을 갖는 초공동화 수중체에 대한 실험적 연구 (Experimental Study on Supercavitated Body with Static Angle-of-attack)

  • 이준희;백부근;김경열;김민재;김선홍;이승재
    • 대한조선학회논문집
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    • 제56권6호
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    • pp.541-549
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    • 2019
  • In the present study, we investigated planing forces of supercavitated bodies by using the supercavitation shape produced by the disk type cavitator. The cavity shapes are observed to find the immersion draft and planing angle when the stern of the supercavitated body is partially immersed in the water. To make the planing the angle-of-attack (AOA) of the supercavitated body is varied statically against the main flow and the planing tests are carried out for different body shapes that are changed systematically. The drag, lift and pitch moment acting on the body are measured to understand the relation between the planing force and the immersion draft of the supercavitated body. It is found that the planing force increased in general linearly with the immersion draft ratio and the planing angle is certainly not proportional to the immersion draft ratio.

재료의 표면파괴와 마멸특성에 대한 표면 형상의 영향 (The effect of surface profile on wear and scuffing of bounda lubricated sliding surfaces)

  • 오세두;이영제
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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    • pp.64-71
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    • 2001
  • In this paper the ball-on-disk type sliding tests with boundary lubricated steels were carried out to verify the relation between surface profiles and wear as well as scuffing. Three kinds of surface roughness and asperity radius were produced on AISI 1045 steels using the different processes of grinding and polishing. Frictional forces and time to scuffing were measured. Also, the shape and amount of wear particles were analyzed to compare with original profiles. From the tests, it was confirmed that the size of wear particles are very related to original surface profile. The time to failures and wear amounts were sensitive to the surface spacing. The large surface spacing shows much longer sliding life and smaller wear amount than the others. Time to scuffing was increased with increasing surface profile spacing. The size of wear particles was increased and the amount was decreased with increasing surface profile spacing. Wear volume and wear rate K were decreased with increasing surface profile spacing. And after sliding tests, surface cracks of inner parts of the wear track occurred scuffing were observed and compared the differences about each specimen having the different surface profile spacing.

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자동차 이차전지 제조를 위한 알루미늄과 무산소동의 레이저 용접특성 (Laser Welding Characteristics of Aluminum and Copper Sheets for Lithium-ion Batteries)

  • 강민정;박태순;김철희;김정한
    • Journal of Welding and Joining
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    • 제31권6호
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    • pp.58-64
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    • 2013
  • Several joining methods involving resistance welding, laser welding, ultrasonic welding and mechanical joining are currently applied in manufacturing lithium-ion batteries. Cu and Al alloys are used for tab and bus bar materials, and laser welding characteristics for these alloys were investigated with similar and dissimilar material combinations in this study. The base materials used were Al 1050 and oxygen-free Cu 1020P alloys, and a disk laser was used with a continuous wave mode. In bead-on-plate welding of both alloys, the joint strength was higher than the strength of O tempered base material. In overlap welding, the effect of welding parameters on the tensile shear strength and bead shape was evaluated. Tensile shear strength of overlap welded joint was affected by interfacial bead width and weld defect formation. The tensile-shear specimen was fractured at the heat affected zone by selecting proper laser welding parameters.

램프 형상에 대한 램프 상의 로드/언로드 동특성 해석 (Load/unload Dynamics of Slider on Ramp for Various Ramp Shapes)

  • 박경수;박노철;양현석;박영필;이용현
    • 한국소음진동공학회논문집
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    • 제15권11호
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    • pp.1248-1254
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    • 2005
  • L/UL(Load/unload) mechanism has been widely used in SFF(Small form factor) HDD because L/UL technology has many advantages such as an increase of areal density, reduction of power consumption and improvement of shock resistance. In this system, the most important design goal is no slider-disk contact and fast air-hearing breaking during L/UL process. To do so, we should consider many design parameters related to L/UL system. The ramp shape is the most dominant component among parameters which dramatically affect the L/UL performance. This paper makes an advanced ramp model using ANSYS/LS-DYNA. Through this FE model, this paper investigates the effect of initial ramp slope and location of air-bearing breaking. From the experiment for three different ramps, we also verify that experimental results agree with simulation results. We conclude that the ramp design should have small ramp slope at the moment which a suspension tap contacts with ramp and large ramp slope after air-bearing breaking in order to improve L/UL Performance.

브레이크의 스퀼 저감을 위한 로터 형상변경 파라메터 해석 (Parameter Analysis of Rotor Shape Modification for Reduction of Squeal Noise)

  • 이현영;오재응;차병규;조용구;이정윤
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.820-825
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    • 2004
  • This paper deals with friction-induced vibration of disc brake system under constant friction coefficient. A linear, finite element parameter model to represent the floating caliper disc brake system is proposed. The complex eigenvalues are used to investigate the dynamic stability and in order to verify simulations which are based on the FEM model, the experimental modal test and the dynamometer test are performed. The comparison of experimental and simulation results shows a good agreement and the analysis indicates that mode coupling due to friction force is responsible for disc brake squeal. And squeal type instability is investigated by using the parametric rotor simulation. This indicates parameters which have influence on the propensity of brake squeal. This helped to validate the FEM model and establish confidence in the simulation results. Also they may be useful during real disk brake model.

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DVD 드라이브 내에서의 유동 및 유동소음 특성에 관한 수치적 연구 (A Numerical Study on the Characteristic of Airflow and Aeroacoustic Noise in DVD Drive)

  • 유승원;이종수;민옥기;김수경
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 추계학술대회논문집
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    • pp.759-764
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    • 2000
  • The accurate prediction of aeroacoustic analysis is necessary for designers to control and reduce airflow-induced sound pressure levels in high speed rotating DVD drives. This paper focuses on the numerical prediction of airflow-induced sound in DVD drives. Computational fluid dynamics(CFD) is first conducted to evaluate flow field characteristics due to the high-speed disk rotation, and to support the acoustic analysis. The acoustic analogy based on Ffowcs Williams-Hawkings(FW-H) equation is adopted to predict aeroacoustic noise patterns. The integral solution for quadrupole volume source is included to identify the turbulence noise generated inside the DVD tray. The strength of sound pressure level with respect to rotating speed is discussed to meet upfront demand on the high fidelity product development. The present study also focuses on the noise directivity and examines how much the sound noise is sensitive to change in rotating speed. Near-field noise is strongly affected by the flow field characteristic, which is caused by the complex shape of the tray. For a mid-field, the quadrupole noise play as a counterpart of thickness noise or loading noise, so it generates different sound noise patterns compared with those in the near field.

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고고도 모사를 위한 축소형 디퓨저의 성능 특성에 대한 수치적 연구 (A Numerical Study on Performance Characteristics of a Subscale Diffuser for High-Altitude Simulation)

  • 정봉구;임경진;조성휘;김홍집;전준수;고영성;김승한;한영민
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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    • pp.570-573
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    • 2012
  • 고고도 모사를 위한 축소형 디퓨저의 성능특성을 파악하기 위해 수치적 연구를 수행하였다. 입구길이를 노즐 출구직경과 비교해 0%, 50%, 100%로 변화시켰고, 디퓨저 목의 길이는 디퓨저 목의 직경과 비교해 3, 5, 7, 8, 12로 다양화하여 수치해석하고 실제 모사실험 값과 비교하였다. 그 결과 디퓨저의 입구길이가 짧아질수록 plume의 형상은 수축되었다. 또한, 디퓨저의 이차목 길이가 디퓨저 지름의 최소 7~8배보다 작으면 내부에 마하디스크가 형성되어 압력의 급격한 상승을 일으킨다.

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Design of muon production target system for the RAON μSR facility in Korea

  • Jeong, Jae Young;Kim, Jae Chang;Kim, Yonghyun;Pak, Kihong;Kim, Kyungmin;Park, Junesic;Son, Jaebum;Kim, Yong Kyun;Lee, Wonjun;Lee, Ju Hahn
    • Nuclear Engineering and Technology
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    • 제53권9호
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    • pp.2909-2917
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    • 2021
  • Following the launch of Rare Isotope Science Project in December 2011, a heavy ion accelerator complex in South Korea, named RAON, has since been designed. It includes a muon facility for muon spin rotation, relaxation, and resonance. The facility will be provided with 600 MeV and 100 kW (one-fourth of the maximum power) proton beam. In this study, the graphite target in RAON was designed to have a rotating disk shape and was cooled by radiative heat transfer. This cool-down process has the following advantages: a low-temperature gradient in the target and the absence of a liquid coolant cooling system. Monte Carlo simulations and ANSYS calculations were performed to optimize the target system in a thermally stable condition when the 100 kW proton beam collided with the target. A comparison between the simulation and experimental data was also included in the design process to obtain reliable results. The final design of the target system will be completed within 2020, and its manufacturing is in progress. The manufactured target system will be installed at the RAON in the Sindong area near Daejeon-city in 2021 to carry out verification experiments.