• Structural Engineering and Mechanics
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• 제66권4호
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• pp.505-513
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• 2018

Steam flooding is widely used in heavy oil reservoir with coupling effects among the formation temperature change, fluid flow and solid deformation. The effective stress, porosity and permeability in this process can be affected by the multi-physical coupling of thermal, hydraulic and mechanical processes (THM), resulting in a complex interaction of geomechanical effects and multiphase flow in the porous media. Quantification of the state of deformation and stress in the reservoir is therefore essential for the correct prediction of reservoir efficiency and productivity. This paper presents a coupled fluid flow, thermal and geomechanical model employing a program (MATLAB interface code), which was developed to couple conventional reservoir (ECLIPSE) and geomechanical (ABAQUS) simulators for coupled THM processes in multiphase reservoir modeling. In each simulation cycle, time dependent reservoir pressure and temperature fields obtained from three dimensional compositional reservoir models were transferred into finite element reservoir geomechanical models in ABAQUS as multi-phase flow in deforming reservoirs cannot be performed within ABAQUS and new porosity and permeability are obtained using volumetric strains for the next analysis step. Finally, the proposed approach is illustrated on a complex coupled problem related to steam flooding in an oil reservoir. The reservoir coupled study showed that permeability and porosity increase during the injection scenario and increasing rate around injection wells exceed those of other similar comparable cases. Also, during injection, the uplift occurred very fast just above the injection wells resulting in plastic deformation.

• Korean Chemical Engineering Research
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• 제52권2호
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• pp.154-165
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• 2014

최근 수평시추, 수압파쇄 등의 기술발전에 따라 셰일가스, 셰일오일, 석탄층 메탄가스 등 비전통자원개발이 활성화 되었다. 이러한 기술발전으로 생산성이 향상되었지만, 화학약품이 포함된 수압파쇄 유체와 오일, 가스와 고농도의 염과 방사성 물질을 함유하는 생산수가 가스 생산중 발생하게 된다. 이같이 생성된 대량의 폐수에 따른 부정적인 환경적 요인은 비전통자원개발에 주요 장애요소로 급격히 대두되고 있다. 본 연구에서는 비전통자원개발에 따른 회수수와 생산수의 처리방법에 대한 융합적인 토대를 제시하고, 새롭게 떠오르는 다양한 수처리 기술을 총설하고자 한다. 비전통 자원개발 현장에 적용 가능한 기본적인 분리공정인 막분리, 증발, 결정화, 탈염공정 기술을 소개하고 또한 대량의 수자원을 사용하는 비전통자원개발의 특성상 물의 재이용 및 재활용이 가능한 기술을 소개하고자 한다.

• 대한지하수환경학회지
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• 제6권3호
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• pp.152-157
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• 1999

지하 저장 유류 탱크로부터의 기름 유출이나 쓰레기 매립장으로부터의 침출수는 양질의 지하수 자원에 대한 오염원으로 널리 인지되고 있다. 지하 대수층에 유입된 오염물질의 이동성은 지하수 흐름에 의존하며 이에 관련된 수리상수의 결정은 중요한 과제가 된다. 본 연구의 목적은 사질토로 구성된 실내 자유면 대수층 모형을 구축하여 대수층의 수리상수를 기존의 방법들을 이용하여 결정, 비교함으로써 최적의 수리상수를 결정하는데 있다. 자유면 대수층의 저장율을 나타내는 비산출량( $S_{y}$)온 중력배수법을 적용하여 단위 수위 강하에 대한 단위 면적당 배출수의 용적을 대수층 깊이별로 측정하였다. 또한 수리전도도는 실내 모형이 가지는 제한성 즉 불 투수 경계에 의한 간섭효과를 배제하기 위하여 3가지의 다른 방법 (정수위법. Dupuit Approximation, Slug Test)을 이용하여 결정하였다. 실험결과 자유면 사질 대수층의 비산출율은 평균 0.20로서 이는 타 연구결과와 잘 일치하였으며 대수층 깊이에 따라 0.17 - 0.23 사이의 비교적 적은 편차를 보여 대수층의 균질성을 확인할 수 있었다. 반면에 정수위 측정법에 의한 수리전도도는 0.77 cm/min. Dupuit Approximation은 5.33 cm/min, Slug Test 중 Bouwer & Rice 방법은 5.85 cm/min 그리고 Hvorslev 제안식은 7.49 cm/min의 측정치를 나타내었다. 이로써 가장 낮은 관측치를 보인 정수위법을 제외한 다른 방법들은 비교적 근사한 수치를 나타내어 자유면 대수층의 수리전도도 측정 시 정상류 흐름하에 Dupuit Approximation에 의한 방법이나 Slug Test에 의한 방법들이 비교적 좋은 결과를 나타냄을 알 수 있었다.

• 드라이브 ㆍ 컨트롤
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• 제17권2호
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• pp.55-62
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• 2020

There are two types of IMV for MCV, the spool type and the poppet type. The spool type is used in the existing excavator MCV and easily meets large-capacity flow conditions, but has a flow force problem which affects the spool control. The poppet type stably blocks the flow and has excellent rapid response. However, the larger the capacity, the larger the diameter of the poppet needed, requiring a strong spring to withstand the oil pressure. In this study, a bi-directional three-stage IMV for MCV that can be used in medium and large hydraulic excavators was proposed. This is a poppet type, enabling bi-directional flow control and resolves the problem of proportional solenoid suction force limitation. To investigate the validity of the proposed valve, the system was mathematically modeled and the static and dynamic characteristics were investigated through the simulation using commercial software. It has been concluded that the reverse flow is possible in a regeneration circuit and that the proposed IMV can be used to perform various excavation modes.

• 한국유체기계학회 논문집
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• 제19권6호
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• pp.68-74
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• 2016

Hydraulic fracturing of wells during oil and gas (O&G) exploration consumes large volumes of fresh water and generates larger volumes of contaminated wastewater with high salinity. It is critical to treat and reuse the O&G wastewater in a cost-effective and environmentally sound manner for sustainable industrial development and for meeting stringent regulations. Recently, forward osmosis (FO) has been examined if it is a promising solution for treatment and desalination of complex industrial streams and especially fracturing flowback and produced waters. In the present study, the performances of a plate-and-frame FO membrane element and a module (6 elements combined in series) were investigated for concentrating high TDS wastewater. An FO module has achieved up to 64 % water recovery (i.e., concentration factor of 2.76) from 10,000 ppm wastewaters and can concentrate feed streams salinities to greater than 30,500 ppm.

• 한국전자통신학회논문지
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• 제15권5호
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• pp.949-958
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• 2020

차량을 구성하는 엔진, 미션, 현가, 제동, 조향장치 등 다양한 장치 중에서 현가 장치는 타이어와 차체 사이에 설치되어 노면에 의한 차량의 진동을 억제하여 승차감을 향상시키고 차륜과 노면 사이에 적절한 접지력을 유지시켜 차량의 조정안정성을 향상시키는 등 차량역학적인 측면에서 많은 영향을 미치는 장치 중의 하나이다. 본 연구에서는 차량용 현가 장치의 충격 흡수기를 실제 특성과 유사한 상세 모델로 모델링하고, 충격 흡수기의 주요 설계변수의 불확실성을 통계적으로 고려하여 설계변수의 불확실성이 현가 장치의 동적 특성에 미치는 영향에 대하여 연구하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제12권3호
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• pp.201-213
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• 2012

A gear type lubrication pump is an essential component of the powertrain and has a major role for supplying oil to the gears and bearings in automatic transmission with a hydraulic clutch. Therefore, the durability test code design of lubrication pump is very important to ensure the reliability of the entire transmission and the vehicle. In this study, the design process for the life testing of lubrication pump has been generalized by four steps. The four design steps of the life testing of lubrication pump consist of the configuration of load spectrum, rain flow counting and analysis of load level, the equivalent damage assessment and test code generation. In fact, the load spectrum should be obtained from the field operating condition but that kind of data is the top secret of manufacturers. This is not open to the public in general. So we could use the artificially simulated load spectrum instead of field obtained one and focused on the development of the general process for designing the life test of a gear type lubrication pump. Reliability goals for lubrication pump, pressure, torque, temperature and load spectrum, if present, as appropriate for the given test conditions, accelerated life testing for the lubrication pump can be designed by the developed design steps.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.520-523
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• 2000

Phenol and other phenolic compounds are common constituents of aqueous effluents from processes such as polymeric resin production, oil refining and cokeing plants. Phenol is a both toxic and lethal of fish at relatively low concentrations e.g. 5-25 mg/L and imparts objectionable tastes to drinking water at far lower concentration. Therefore, the treatment of phenol effluent is important. Among the various techniques of phenol wastewater treatment, microbial teratment is a popular process. The breakdown of phenols by microorganisms has recived considerable attention, because of its biochemical interest and its industrial importance in effluent treatment. This research was performed to investigate the dynamics of microbial community, biofilm growth and the comparison of phenol removal efficiency by RBC (Rotating Biological Contactor) using Rhodococcus sp. EL-GT The experiment was carried out at rotating speed of 10ppm and hydraulic retention time of 7 hours. As time passed, phenol removal efficiency was gained highly. The RBC using Rhodococcus sp. EL-GT completely degraded 15 mM.

• 유공압시스템학회논문집
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• 제4권4호
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• pp.1-7
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• 2007

Flow rate is one of the important variables for precise motion control and detection of the faults and fluid loss in many hydraulic components and systems. But in many cases, it is not easy to measure it directly. The orifice area of a servo valve by which the fluid flows is one of key factors to monitor the flow rate. In this paper, we have constructed an estimation algorithm for the effective orifice area by using the model of a servo valve cylinder control system and Kalman filter algorithm. Without geometry information about the servo valve, it is shown that the effective orifice area can be estimated by using only displacement and pressure data corrupted with noise. And the effect of the biased sensor data and system parameter errors on the estimation results are discussed. The paper reveals that sensor calibration is important in accurate estimation and plausible parameter data such as oil bulk modulus and actuator volume are acceptable for the estimation without any error. The estimation algorithm can be used as an useful tool for detecting leakage, monitoring malfunction and/or degradation of the system performance.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.11-19
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• 2004

When pile foundation constructed by driving method, it is desirable to perform monitoring and estimation of pile drivability and bearing capacity using some suitable tools. Dynamic Pile Monitoring yields information regarding the hammer, driving system, and pile and soil behaviour that can be used to confirm the assumptions of wave equation analysis. Dynamic Pile Monitoring is performed with the Pile Driving Analyser. The Pile Driving Analyser (PDA) uses wave propagation theory to compute numerous variables that fully describe the condition of the hammer-pile-soil system in real time, following each hammer impact. This approach allows immediate field verification of hammer performance, driving efficiency, and an estimate of pile capacity. The PDA has been used widely as a most effective control method of pile installations. A set of PDA test was performed at the site of Donghea-1 Gas Platform Jacket which is located east of Ulsan. The drilling core sediments of location of jacket subsoil are composed of mud and sand, silt. In this case study, the results of PDA test which was applied to measurement and estimation of large diameter open ended steel pipe pile driven by underwater hydraulic hammer, MHU-800S, at the marine sediments were summarized.