• 제목/요약/키워드: Hydraulic line

검색결과 332건 처리시간 0.16초

Analysis of Vibration Noise Spectrum in Motor-Driven Power Steering System (Motor-Driven Power Steering 시스템의 진동 소음 스펙트럼 분석)

  • Park, Han Young;Kim, Jin Young;Kang, Joonhee
    • Journal of Sensor Science and Technology
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    • 제27권2호
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    • pp.126-131
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    • 2018
  • Unlike the hydraulic power steering (HPS) system, which operates by the high pressure of a fluid obtained from the engine power, the motor-driven power steering (MDPS) system uses an electric motor to steer the wheel without consuming engine power. To steer the wheel with an electric motor, a worm wheel and a worm gear rotating between the steering shaft and motor are required. Any imperfection during the construction of an MDPS system or in a composing part creates noise and vibration, which can be sensed by a driver. To solve the noise and vibration problems, each part must be designed to not resonate with other parts. In this work, we developed the measurement and analysis systems to obtain the noise and the vibration of an automobile MDPS system. A signal analyzer was equipped with a 96 kHz, 24-bit ADC and a 150 MHz digital signal processor. The predetermined threshold value of the vibration in the MDPS system was used to determine the pass/fail, and the results were displayed on the screen. Our system can be used in the fabrication line to swiftly determine any imperfections in the MDPS system construction.

Optimal Design of Storm Sewer by Computations of Feasible Hydraulic Gradient Line (합리적 동수위 계산을 통한 최적 배수관로 설계)

  • Yoo, Hee-Sang;Kim, Mun-Mo;Ahn, Won-Sik
    • Proceedings of the Korea Water Resources Association Conference
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    • 한국수자원학회 2009년도 학술발표회 초록집
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    • pp.1585-1589
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    • 2009
  • 최근 빈발하는 국지성 호우나 태풍에 의한 집중호우로 도시지역의 내배수불량으로 인하여 저지대 및 지하공간의 침수현상이 빈번히 야기하고 있는 실정이다. 특히 연안이나 외수위의 영향으로 강제배수가 요구되는 지역인 경우에는 개발에 앞서 선결해야할 중요한 재해저감대책 중의 하나이다. 이에 본 연구에서는 연안의 해수면 및 하천 홍수위로 인한 계획단지 내 배수관로의 동수위 산정을 위한 유출모의를 수행하였다. 연안저지대의 순성토 지역인 경우 동수위 계산에 따른 성토량에 의한 비용이 전체 공사비 결정 요인의 가장 큰 부분을 차지하고 있으므로 이에 따른 경제적이면서 치수안전도를 증가시킬 수 있는 계산 방법을 정립하는 것은 선결되어야 할 문제이다. 이를 위해 도시유역에 범용적으로 사용되고 있는 SWMM 모형을 활용하였다. SWMM 모형 중에서 EXTRAN 블록을 통한 유출모의는 관거내 동수경사를 계산하여 배수, 역류, 압력류, 월류까지도 모의할 수 있다. 다양한 조건으로 배수관로의 설계를 통한 동수위와 성토고를 분석하여 조건별 경제성과 치수안전도를 검토할 수 있으나 관로 크기, 경사, 방향 등을 우선하여 변경해가면서 최적안을 확인하였다. 검토된 계산 절차에 따라서 향후 지형적으로 유사한 지역에서의 배수시스템 설계에 적용 및 기존 배수관망 재설계 및 확장 등의 검토에 효과적으로 적용할 수 있을 것이다.

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A Preliminary Analysis of Large Loss-of-Coolant Induced by Emergency Core Coolant Pipe Break in CANDU-600 Nuclear Power Plant

  • Ion, Robert-Aurelian;Cho, Yong-Jin;Kim, In-Goo;Kim, Kyun-Tae;Lee, Jong-In
    • Proceedings of the Korean Nuclear Society Conference
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    • 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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    • pp.435-440
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    • 1996
  • Large Loss-of-Coolant Accidents analyzed in Final Safety Analysis Reports are usually covered by Reactor Inlet Header. Reactor Outlet Header and Primary Pump Suction breaks as representative cases. In this study we analyze the total (guillotine) break of an Emergency Core Cooling System (ECCS) pipe located at the ECCS injection point into the Primary Heat Transport System (PHTS). It was expected that thermal-hydraulic behaviors in the PHT and ECC systems are different from those of a Reactor Inlet Header break, having an equivalent break size. The main purpose of this study is to get insights on the differences occurred between the two cases and to assess these differences from the phenomenon behavior point of view. It was also investigated whether the ECCS line break analysis results could be covered by header break analysis results. The study reveals that as the intact loop has almost the same behavior in both analyzed cases. broken loop behavior is different mostly regarding sheath temperature in the critical core pass and pressure decrease in the broken Reactor Inlet Header. Differences are also met in the ECCS behavior and in event sequences timings.

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Effects of Fracture Intersection Characteristics on Transport in Three-Dimensional Fracture Networks

  • Park, Young-Jin;Lee, Kang-Kun
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 한국지하수토양환경학회 2001년도 추계학술발표회
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    • pp.27-30
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    • 2001
  • Flow and transport at fracture intersections, and their effects on network scale transport, are investigated in three-dimensional random fracture networks. Fracture intersection mixing rules complete mixing and streamline routing are defined in terms of fluxes normal to the intersection line between two fractures. By analyzing flow statistics and particle transfer probabilities distributed along fracture intersections, it is shown that for various network structures with power law size distributions of fractures, the choice of intersection mixing rule makes comparatively little difference in the overall simulated solute migration patterns. The occurrence and effects of local flows around an intersection (local flow cells) are emphasized. Transport simulations at fracture intersections indicate that local flow circulations can arise from variability within the hydraulic head distribution along intersections, and from the internal no flow condition along fracture boundaries. These local flow cells act as an effective mechanism to enhance the nondiffusive breakthrough tailing often observed in discrete fracture networks. It is shown that such non-Fickian (anomalous) solute transport can be accounted for by considering only advective transport, in the framework of a continuous time random walk model. To clarify the effect of forest environmental changes (forest type difference and clearcut) on water storage capacity in soil and stream flow, watershed had been investigated.

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A Numerical Method to Calculate Drainage Time in Large Transmission Pipelines Filter (대구경 관로의 배수시간 산정을 위한 수치해석 기법)

  • Shin, Byoung-Ho;Choi, Doo-Yong;Jeong, Kwansue
    • Journal of Korean Society of Water and Wastewater
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    • 제31권6호
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    • pp.511-519
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    • 2017
  • Multi-regional water supply system, which installed for supplying multiple water demands, is characterized by large-sized, long-distance, tree-type layout. This system is vulnerable to long-standing service interruption when a pipe breaks is occurred. In this study, a numerical method is proposed to calculate drainage time that directly affects time of service interruption. To begin with, governing equations are formulated to embed the delayed drainage effect by the friction loss, and to resolve complicated connection of pipelines, which are derived from the continuity and energy equations. The nonlinear hydraulic equations are solved by using explicit time integration method and the Newton-Raphson method. The developed model is verified by comparing the result with analytical solution. Furthermore, the model's applicability is validated by the examples of pipelines in serial, in parallel, and complex layout. Finally, the model is utilized to suggest an appropriate actions to reduce the deviation of draining time in the C transmission line of the B multi-regional water supply system.

Flow Network Analysis for the Flow Control of a Main Cooling Water System in the HANARO Fuel Test Loop (하나로 핵연료 시험 루프 주냉각수 계통의 유량 제어에 대한 유동 해석)

  • Park, Young-Chul;Lee, Yong-Sub;Chi, Dae-Yong
    • The KSFM Journal of Fluid Machinery
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    • 제12권5호
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    • pp.7-12
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    • 2009
  • A nuclear fuel test loop(after below, FTL) is installed in the IRI of an irradiation hole in HANARO for testing the neutron irradiation characteristics and thermo hydraulic characteristics of a fuel loaded in a light water power reactor or a heavy water power reactor. There is an in-pile section(IPS) and an out-pile section(OPS) in this test loop. When HANARO is operated normally, the fuel loaded into the IPS has a nuclear reaction heat generated by a neutron irradiation. To remove the generated heat and to maintain the operation conditions of the test fuel, a main cooling water system(MCWS) is installed in the OPS of the FTL. The MCWS is composed of a main cooler, a pressurizer, two circulation pumps, a main heater, an interconnection pipe line and instruments. The interconnection pipeline is a closed loop which is connected to an inlet and an outlet of the IPS respectively. The MCWS is under a cold function test during a start-up period. This paper describes the system flow network analysis results of the flow control of a main cooling water system in the HANARO fuel test loop. It was confirmed through the results that the flow was met the system design requirements.

Development of a Piecewise Bendable Switch System for the Urban Transit MagLev(I) (도시형 자기부상열차용 굴절형 분기장치의 개발(I))

  • Lee, Jong-Min;Jo, Heung-Je;Kim, In-Geun
    • 연구논문집
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    • 통권29호
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    • pp.57-67
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    • 1999
  • This paper presents the status quo of the development of a piecewise bendable switch system for the urban transit MagLev. MagLev system as well as railroad requires switch systems to reach its destination. Requirements of the switch system for commercial lines are high speed operation satisfying about 2-3 minute headway and system reliability, etc. Parallel moving type switch system was installed on the test track of urban transit MagLev in KIMM. In this system, switch operation from one position to another can be done in about 90 seconds. Therefore, we concluded that this system can not satisfy the headway for the commercial lines. We decided to develop a high speed piecewise bendable switch system in which switching can be done in 20 seconds. Designed switch system is very complicated in view of operating mechanism. It consists of 11 segmented girder beams driven by hydraulic cylinders. To gain the idea of a piecewise bendable switch system, we manufactured and tested a 1/5 scale switch model. We are going to construct a full scale piecewise bendable switch system next year.

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A Study on the Control of Multi-Input Hydraulic System for Robot Leg using LQR Technique (LQR 기법을 이용한 로봇다리의 다중입력 유압시스템 제어에 관한 연구)

  • Yoo, Sam-Hyeon;Lim, Soo-Chul
    • Journal of the Korea Institute of Military Science and Technology
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    • 제12권4호
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    • pp.540-547
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    • 2009
  • In the near future, military robots are likely to be substituted for military personnel in the field of battle. The power system of a legged robot is considerably more complex than the one used for a land vehicle because of the coordination and stability issues due to the large number of degree of freedom. In this paper, a servovalve-piston combination system for a straight-line motion of robot leg is modeled as three degree of freedom based on double inputs and single output transfer function. The output is the displacement of piston from neutral. The inputs are valve displacement from neutral and arbitrary load force in this system. LQR(Linear Quadratic Regulator) technique is applied in order to achieve robust stability and fast responses of the system. The Kalman filter loop, rejection of disturbance and noise, riccati equation, filter gain matrix, and frequency domain equality are analyzed and designed.

Seepage Behavior of Sea Dyke Final Closure with Tidal Variation (조위변화에 따른 방조제 끝막이 사석단면의 침투거동)

  • Yoo, Jeon-Yong;Oh, Young-In;Kim, Hyun-Tae;Jeung, In-Young
    • Proceedings of the Korean Geotechical Society Conference
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    • 한국지반공학회 2006년도 춘계 학술발표회 논문집
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    • pp.800-807
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    • 2006
  • Sea dyke construction is simply defined that the cutting procedure of sea water flow. Sea dyke construction is more difficult than in-land construction because it’s placed on deep seabed and exposed sea wave attack. Especially, the final closure of sea dyke is most dangerous due to the fast velocity of tidal flow. The final closure section is consisted with vast rubble and heavy stone gabion, therefore the discharge velocity at land side of final close section is irregularly and sometime occur the fast discharge velocity. In this study, the seepage model test performed to evaluate seepage behavior with tidal variation of final closure and continuous sea dyke section such as discharge velocity, hydraulic gradient, and phreatic line. Based on the seepage model test results, the maximum discharge velocity of final closure section is 1.7m/sec. Also the local discharge velocity increment and vortex is occurred.

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Thermal-Mixing Analyses for Safety Injection at Partial Loop Stagnation of a Nuclear Power Plant

  • Hwang, Kyung-Mo;Kim, Kyung-Hoon
    • Journal of Mechanical Science and Technology
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    • 제17권9호
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    • pp.1380-1387
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    • 2003
  • When a cold HPSI (High pressure Safety Injection) fluid associated with an overcooling transient, such as SGTR (Steam Generator Tube Rupture), MSLB (Main Steam Line Break) etc., enters the cold legs of a stagnated primary coolant loop, thermal stratification phenomena will arise due to incomplete mixing. If the stratified flow enters the downcomer of the reactor pressure vessel, severe thermal stresses are created in a radiation embrittled vessel wall by local overcooling. As general thermal-hydraulic system analysis codes cannot properly predict the thermal stratification phenomena, RG 1.154 requires that a detailed thermal-mixing analysis of PTS (pressurized Thermal Shock) evaluation be performed. Also. previous PTS studies have assumed that the thermal stratification phenomena generated in the stagnated loop side of a partially stagnated primary coolant loop are neutralized in the vessel downcomer by the strong flow from the unstagnated loop. On the basis of these reasons, this paper focuses on the development of a 3-dimensional thermal-mixing analysis model using PHOENICS code which can be applied to both partial and total loop stagnated cases. In addition, this paper verifies the fact that, for partial loop stagnated cases, the cold plume generated in the vessel downcomer due to the thermal stratification phenomena of the stagnated loop is almost neutralized by the strong flow of the unstagnated loop but is not fully eliminated.