• Title/Summary/Keyword: Hydraulic well

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A parametric study on the performance of heat pump using standing column well(SCW) (스탠딩컬럼웰(SCW)을 적용한 지열히트펌프의 성능에 대한 매개변수 연구)

  • Chang, Jae-Hoon;Park, Du-Hee
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.625-630
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    • 2010
  • Parametric study was performed using the SCW numerical model for evaluating the performance of the SCW. The five ground related parameters, which are porosity, hydraulic conductivity, thermal conductivity, specific heat, geothermal gradient, and five SCW design parameters, which are pumping rate, well depth well diameter, dip tube diameter, bleeding rate, were used in the study. Numerical simulations were performed for short-term (24-hour) simulation. The study results indicate that the parameters that have important influence on the performance of SCW were hydraulic conductivity, thermal conductivity, geothermal gradient, pumping rate, and bleeding rate. Overall, this study showed that various factors had a cumulative influence on the performance of the SCW, and a numerical simulation can be used to accurately predict the performance of the SCW.

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Evaluation of Well Production by a Riverbank Filtration Facility with Radial Collector Well System in Jeungsan-ri, Changnyeong-gun, Korea (경남 창녕군 증산리 일대 방사집수정을 활용한 강변 여과수 개발량 평가)

  • Lee, Eun-Hee;Hyun, Yun-Jung;Lee, Kang-Kun;Kim, Hyoung-Soo;Jeong, Jae-Hoon
    • Journal of Soil and Groundwater Environment
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    • v.15 no.4
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    • pp.1-12
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    • 2010
  • Well production by a riverbank filtration facility with multi-radial collector well systems in Jeungsan-ri, Changnyeong gun, Korea was evaluated. In this study, the drawdown at collector wells due to pumping and groundwater inflow rates along the horizontal arms of the collector wells were computed through numerical simulations. Sensitivities of the well production to hydraulic conductivity and well flow coefficient, which represents the resistance to the flow from the aquifer to the horizontal arms, were analyzed. Simulation results showed that, with given proposed pumping rate conditions, the drawdown in the caisson exceeded maximum drawdown constraints in the study site and the adjustment of the pumping rate at each well is needed. The drawdown is affected by the hydraulic conductivity of the main aquifer and the well flow coefficient, which means the profound field investigation of the study site is needed to accurately estimate the efficiency of riverbank filtration through radial collector wells.

Satisfaction Survey of Training to Prevent Marine Accidents on Hydraulic Clutch in Small Ships (소형선박 유압클러치 장치의 해양사고 예방 교육 만족도에 관한 조사)

  • Kim, Young-Un
    • Journal of Fisheries and Marine Sciences Education
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    • v.26 no.5
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    • pp.966-978
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    • 2014
  • Currently, majority small ship's clutch for power transmission to propeller relies on multi plate hydraulic clutch regardless its size. Most of the small ships do not have a spare equipments of clutch. Furthermore, many ship engineers do not have an ability as well as enough experience to solve this problem related to the hydraulic clutch during the voyage. Therefore, any small problems cause many serious marine accidents. Once the clutch has problem, almost of all ships can not sail by itself anymore and it must be towed by salvage boat, maritime police ships, or fish guidance boat etc. In this case, all the accidents will be categorized as a marine accident and they all need to go through marine accident court inquiries. In this study, an understanding of each crew on hydraulic clutch system has been profoundly measured. Furthermore, the knowledge on an emergency navigation protocol of each crew has been also profoundly checked. Additionally, various surveys on hydraulic clutch classes has been performed and its satisfaction of crews on this topic have been carefully checked based on various feedback from students who took these courses. All of the above data from this study will be used to reduce marine accidents in current marine industry.

Deformation behaviours of SS304 tubes in pulsating hydroforming processes

  • Yang, Lianfa;Wang, Ninghua;He, Yulin
    • Structural Engineering and Mechanics
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    • v.60 no.1
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    • pp.91-110
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    • 2016
  • Tube hydroforming (THF) under pulsating hydraulic pressures is a novel technique that applies pulsating hydraulic pressures that are periodically increased to deform tubular materials. The deformation behaviours of tubes in pulsating THF may differ compared to those in conventional non-pulsating THF due to the pulsating hydraulic pressures. The equivalent stress-strain relationship of metal materials is an ideal way to describe the deformation behaviours of the materials in plastic deformation. In this paper, the equivalent stress-strain relationships of SS304 tubes in pulsating hydroforming are determined based on experiments and simulation of free hydraulic bulging (FHB), and compared with those of SS304 tubes in non-pulsating THF and uniaxial tensile tests (UTT). The effect of the pulsation parameters, including amplitude and frequency, on the equivalent stress-strain relationships is investigated to reveal the plastic deformation behaviours of tubes in pulsating hydroforming. The results show that the deformation behaviours of tubes in pulsating hydroforming can be well described by the equivalent stress-stain relationship obtained by the proposed method. The amplitude and frequency of pulsating hydraulic pressure have distinct effects on the equivalent stress-strain relationships-the equivalent stress becomes augmented and the formability is enhanced with the increase of the pulsation amplitude and frequency.

An analysis on power regeneration of hydrostatic pressure exchanger (정수압방식 동력회수장치의 구동동력 절감량 해석)

  • Ham, Y.B.;Choi, J.H.;Jeong, H.S.;Park, S.J.;Park, J.H.;Yun, S.N.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.4 no.3
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    • pp.7-12
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    • 2007
  • This paper presents an energy saving hydrostatic pressure exchanger for sea water desalination equipment. In a reverse osmosis(RO) system for desalinating sea water, more than 70 percent of the supplied sea water, brines which were impassable through RO membrane are bypassed, resulting in high energy losses. In this paper, a hydrostatic pressure exchanger consisting of an embedded water hydraulic piston motor and a water hydraulic piston pump was proposed and investigated in order to recover the energy of the bypassed brines. The pressurized brines are supplied to the embedded water hydraulic piston motor as power sources and the water hydraulic piston pump is driven by the output torque of the embedded water hydraulic piston motor as well as electric motor. Consequently, the energy of the bypassed brines can be recovered. To examine the electric energy saving characteristics of the hydrostatic pressure exchanger, a simulation model was constructed using commercial software and experiments were conducted. Through the results of simulation and experiment, the feasibility of the electric energy saving effect of the proposed hydrostatic pressure exchanger was investigated.

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Deduction of a Simplified Model for the Hydraulic Actuator for a Low-band Type Suspension System (능동제어식 현가계의 유압 구동장치에 대한 단순화 모델 유도)

  • 김동윤;홍예선;박영필
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.4
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    • pp.27-38
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    • 1994
  • In this paper, a simplified model of a hydraulic actuator system for a low-band type active suspension system is derived. To reduce the order of model, time constants of each chamber in hydraulic system are neglected except that of an accumulator. And the dynamics of a spool in the pressure control valve is regarded as a first-order system. The step response and the frequency response of the simplified second-order simulation model exhibit a good agreement with those of the actual system as well as those of the tenth-order simulation model. It is possible to simplify the tenth-order model to the second-order one. The low-band type active suspension model is built up by combining of a quarter car model test rig to testify the validity of the simplified model. The experimental results of suspension characteristics show that the simplified second-order hydraulic actuator model is reasonable to describe the dynamics of the actual hydraulic actuator system for a low-band type active suspension system.

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A Study on the Hydraulic Vibration Characteristics of the Prefill Check Valve (프리필용 체크밸브의 유압진동 특성에 관한 연구)

  • Park, Jeong Woo;Han, Sung-Min;Lee, Hu Seung;Yun, So-Nam
    • Journal of Drive and Control
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    • v.18 no.3
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    • pp.8-15
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    • 2021
  • A rear axle steering (RAS) system is attached to the rear of medium and large commercial vehicles that transport large cargo. The existing RAS systems are driven by electro-hydraulic actuator (EHA), and most commercialized EHAs consist of electric motors, hydraulic pumps, relief valves, prefill valves and cylinders. The prefill valve required for such EHAs is a type of check valve with extremely low cracking pressure that should not allow RAS to have noise or vibration, and the prefill valve prevents system negative pressure as well as unstable operation. Most papers on this topic rely on experiments to predict valve performance, and theoretically detailed modeling of valves or pipelines is performed, but it is very rare to evaluate hydraulic vibration characteristics by analysing everything from hydraulic pumps to valves comprehensively. In this study, we proposed an experimental circuit that can predict the performance of the prefill valve. The study also analysed the pressure-flow pulsation that is transmitted to the valve through the pipeline, and how the transmitted pressure-flow pulsation affects the valve vibration.

A Study Stability Analysis of a PWM Controlled Hydraulic Equipment (PWM 제어되는 유압장치의 안정성 해석)

  • ;Wennmacher, G.
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.6
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    • pp.1469-1478
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    • 1995
  • PWM control is a kind of nonlinear control. The merits of PWM control of hydraulic equipment are the robustness of the high speed on-off valve and its low price. And it is easily implemented to hydraulic equipments with microcomputer. The high speed on-off valve is directly digitally controlled without any D/A converter. The objectives of this study is to analyze the limit cycle which regularly appear in the position control system using high speed on-off valve, and to give a criterion for the stability of this system. To do this, the nonlinear characteristics of PWM and cylinder friction of this system are described by harmonic linearization and the effects of parameter variations to the system stability are examined theoretically and experimentally. Consequently, the availability of the proposed method is confirmed well.

Fatigue Behavior Analysis of Welded Rod/Knuckle Assembly for Hydraulic Cylinder (용접이음 된 유압 실린더용 로드/너클 조립체의 피로거동 해석)

  • Rhee, Hwanwoo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.4
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    • pp.93-99
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    • 2013
  • Parts and structures such as piston rod and knuckle joint for the use of hydraulic cylinder are often welded together in some fashion, usually due to cost and process effectiveness. Welding strongly affects the material by the process of heating and subsequent cooling as well as by the fusion process with additional filler material. Furthermore, a weld is usually far from being perfect, containing inclusions, pores, cavities, undercuts etc. As a consequence, fatigue failures appear in welded structures mostly at the welds rather than in the base metal, even if the latter contains notches. For this reason, fatigue analyses are of high practical interest for all welded structures under the action of cyclic loads. This paper describes the influence of welding parameters, material combinations and heat treatment on the fatigue behavior of welded cylinder rod. In addition, statistical characterization of stress-life response in weldment of hydraulic cylinder rod are presented.

The Characteristics of Pulsating Flow in a Hydraulic Pipe (유압관로에서 맥동유동 특성에 관한 연구)

  • 모양우;유영태;김지화
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.7
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    • pp.653-665
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    • 2001
  • The characteristics of the pulsating flow in a hydraulic pipe have been investigated. It is necessary to study the power control of the power transmission system in the landing gear system of aircraft and the design of robots. In this system, the power transmission pipeline is composed of a hydraulic system, and the operating flow is unsteady flow. The wave equation varying with frequency is analyzed in order to investigate the characteristics of unsteady flow in such a pipe. This wave equation involves the propagation coefficient in terns of frequency and viscosity. The theoretical result of this wave equation are compared with experimental result. Each wave equation, varying with the propagation coefficient, is analyzed theoretically. then, a sinusoidal wave generator is built in order to make better sinusoidal waves, and a rectifier is built to eliminate the noise from the hydraulic pump. The theoretical results of the wave equation in the flow of viscous fluid agree well with experimental results.

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