• 제목/요약/키워드: Hydraulic efficient

검색결과 258건 처리시간 0.024초

동력 추적 기법을 활용한 직렬형 유압 하이브리드 차량의 제어 방식에 관한 연구 (A study on the control of series hydraulic hybrid vehicle using power follower strategy)

  • 권우상;오주영;송창섭
    • 유공압시스템학회:학술대회논문집
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    • 유공압시스템학회 2010년도 춘계학술대회
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    • pp.49-55
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    • 2010
  • A series hydraulic hybrid vehicle(SHHV) concept has been explored as a potential pathway to an ultra-efficient city vehicle. Improvements in SHHV fuel economy with reduced emissions strongly depend on their supervisory control strategy. Thermostatic control is simple and reliable but it's cause of frequent engine on-off. Therefore, power follower strategy is presented. In this paper, thermostatic control strategy and power follower strategy is compared for the SHHV model developed using AMESim.

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MODELING AND PARAMETER IDENTIFICATION FOR A PASSIVE HYDRAULIC MOUNT

  • Zhang, Y.X.;Zhang, J.W.;Shangguan, W.B.;Feng, Q.Sh.
    • International Journal of Automotive Technology
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    • 제8권2호
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    • pp.233-241
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    • 2007
  • A lumped parameter model is proposed for the analysis of dynamic behaviour of a Passive Hydraulic Engine Mount (PHEM), incorporating inertia track and throttle, which is characterized by effective and efficient vibration isolation behaviour in the range of both low and high frequencies. Most of the model parameters, including volume compliance of the throttle chamber, effective piston area, fluid inertia and resistance of inertia track and throttle are identified by an experimental approach. Numerical predictions are obtained through a finite element method for responses of dynamic stiffness of the rubber spring. The experiments are made for the purpose of PHEM validation. Comparison of numerical results with experimental observations has shown that the present PHEM achieves good performance for vibration isolation.

압력지연삼투 (PRO) 공정에서 유도용액에서의 압력이 유기물 파울링에 미치는 영향 (Effect of Hydraulic Pressure on Organic Fouling in Pressure Retarded Osmosis (PRO) Process)

  • 서동우;윤홍식;윤제용
    • 상하수도학회지
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    • 제29권1호
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    • pp.133-138
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    • 2015
  • Pressure retarded osmosis (PRO) process is one of membrane processes for harvesting renewable energy by using salinity difference between feed and draw solutions. Power is generated by permeation flux multiplied by hydraulic pressure in draw side. Membrane fouling phenomena in PRO process is presumed to be less sever, but it is inevitable. Membrane fouling in PRO process decreases water permeation through membrane, resulting in significant power production decline. This study intended to investigate the effect of hydraulic pressure in PRO process on alginate induced organic fouling as high and low hydraulic pressures (6.5 bar and 12 bar) were applied for 24 h under the same initial water flux. In addition, organic fouling in draw side from the presence of foulant (sodium alginate) in draw solution was examined. As major results, hydraulic pressure was found to be not a significant factor affecting in PRO organic fouling as long as the same initial water flux is maintained, inidicating that operating PRO process with high hydraulic pressure for efficient energy harvesting will not cause severe organic fouling. In addition, flux decline was negligible from the presence of organic foulant in draw side.

항공기 유압유 저장조 내면연마를 위한 슈퍼피니싱 장치 개발에 관한 연구 (Development of Superfinishing Machine to Polish the Inner Surfaces of Aircraft Hydraulic Oil Reservoirs)

  • 최수현;공광주;조영태
    • 한국기계가공학회지
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    • 제19권8호
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    • pp.110-116
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    • 2020
  • Aircraft hydraulic oil reservoirs made with aluminum 7075 have an anodized coating to enable airtightness and corrosion resistance. To maintain a stable oil pressure, the internal surface roughness of the reservoir should be less than approximately 0.2 ㎛. To this end, precision polishing must be performed. However, ensuring the processing quality is challenging, as most polishing operations are performed manually, owing to which, the inner surface roughness is not uniform, and the product quality is irregular. Therefore, we developed a special superfinishing machine to realize the efficient inner polishing of an aircraft hydraulic oil reservoir, by using an abrasive film to improve the process throughput and uniformity. In the experiment involving the superfinishing of an anodized aluminum 7075 cylinder specimen by using the proposed machine, a higher surface roughness than that achieved in the repetitive manual polishing process could be realized.

원심형 혈액펌프의 최적화 수력설계 및 성능해석 (Hydraulic Design Optimization and Performance Analysis of a Centrifugal Blood Pump)

  • 박무룡;유성연;오형우;윤의수
    • 대한기계학회논문집B
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    • 제30권1호
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    • pp.87-94
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    • 2006
  • This paper presents the hydrodynamic design and performance analysis method for a miniaturized centrifugal blood pump using three-dimensional computational fluid dynamics (CFD) code. In order to obtain the hydraulically high efficient configuration of a miniaturized centrifugal blood pump for cardiopulmonary circulation, a well-established commercial CFD code was incorporated considering detailed flow dynamic phenomena in the blood pump system. A prototype of centrifugal blood pump developed by the present design and analysis method has been tested in the mock circulatory system. Predicted results by the CFD code agree very well with in vitro hydraulic performance data for a centrifugal blood pump over the entire operating conditions. Preliminary in vivo animal testing has also been conducted to demonstrate the hemodynamic feasibility for use of centrifugal blood pump as a mechanical circulatory support. A miniaturized centrifugal blood pump developed by the hydraulic design optimization and performance prediction method presented herein shows the possibility of a good candidate for intra and extracorporeal cardiopulmonary circulation pump in the near future.

강원도 어도의 설치 현황 및 I형 아이스하버식 어도 적용성 연구 (Establishment present of fish-road in Kangwondo and Study to apply fish-road is ice harbor 1-type)

  • 최한규;최영수;전영수
    • 산업기술연구
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    • 제26권B호
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    • pp.63-71
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    • 2006
  • The concerned object of the construction industry is environment. It is one of the main purposes of today's construction that human can live reasonably in nature. This study is about the fish-road connecting hydraulic structure in the river with nature. Chapter 2, starting with the general investigation about fish-road and helps comprehension for relatively general fish-road such as necessity, establishment purpose, history, study example, relating domestic law, design condition, consideration and form of fish-road. Chapter 3, containing the present condition of fish-road facilities in Gangwon-Do and thoughts of the problems and general countermeasures of existing fish-road. Chapter 4, Having Examined compatibility by amount of flowing water through hydraulic model test in the Ice harbor I-type model. chapter 5, Analyzation and arrangement to efficient establishment plan of fish-road and the result of the hydraulic model experiment to be beaconed a little in forward fish-road study. In the hydraulic model test result, when we suppose establishment of 1~3 in slope of 1/20, could know that applicable drought flow of the river is $0.06{\sim}3.0m^3/sec$ in case of Ice harbor I-type which transforming Ice harbor that was invented as studying project of the Ministry of Environment.

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파쇄대를 통과하는 해저터널의 수리거동에 관한 연구 (Hydraulic behavior of a subsea tunnel in a ground with fractured-zones)

  • 신종호;최규철
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.1571-1580
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    • 2008
  • Subsea tunnels that link land to island and among nations for transportation, efficient development of limited surface and pursuit of economic development should be designed to support pore water pressure on the lining. It is generally constructed in the bed rock of the sea bottom. When the tunnel excavation face meets fractured-zones below sea bottom, collapse may occur due to an increase of pore water pressure and large inflow. Such an example can be found in the Norwegian subsea tunnel experiences in 1980's. In this study hydraulic behavior of tunnel heading is investigated using numerical method based on the collapse of Norwegian subsea tunnel. The effect of pore water pressure and inflow rate were mainly concerned. Horse-shoe shaped model tunnel which has 50 m depth from the sea bottom is considered. To evaluate hydraulic performance, parametric study was carried out for varying relative permeability. It is revealed that pore water pressure has increased with an increase of sea depth. Especially, at the fractured-zone, pore water pressure on the lining has increased significantly. Inflow rate into tunnel has also increased correspondingly with an increase in sea depth. S-shaped characteristic relation between relative permeability and normalized pore water pressure was obtained.

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근접수치사진측량으로 수리모형해석에 적용 시 최적보간법 평가 (Evaluation of the Optimum Interpolation for Creating Hydraulic Model from Close Range Digital Photogrammetry)

  • 최현
    • 한국측량학회지
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    • 제23권3호
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    • pp.251-260
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    • 2005
  • CCD의 개발은 사진측량에 많은 발전을 이루었다. 본 연구는 근접수치사진측량으로 수리모형 해석시 지형 보간최적분석기법에 관한 연구이다. 먼저 근접수치사진측량과 삼각수준측량으로 수리모형의 상사성을 분석하기 위해 통계분석의 일종인 T-검정을 실시하였다 그리고 수치사진측량으로 분석한 수리모형해석을 컴퓨터로 실제지형과 비슷한 형상을 가지는 수치표고모형을 만들기 위해 역거리, 크리깅, 최근린, 불규칙삼각망 보간법 중에서 수리모형 적용에 적합한 최적 보간법을 제시하였다. 수리모형에 대한 기하학적 상사분석을 위해 보간법을 적용 결과, 크리깅 보간법과 불규칙삼각망 보간법이 효율적인 것으로 판단되었다

Efficient flexible boundary algorithms for DEM simulations of biaxial and triaxial tests

  • Liu, Donghai;Yang, Jiaqi
    • Geomechanics and Engineering
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    • 제23권3호
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    • pp.189-206
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    • 2020
  • The accurate modeling of boundary conditions is important in simulations of the discrete element method (DEM) and can affect the numerical results significantly. In conventional triaxial compression (CTC) tests, the specimens are wrapped by flexible membranes allowing to deform freely. To accurately model the boundary conditions of CTC, new flexible boundary algorithms for 2D and 3D DEM simulations are proposed. The new algorithms are computationally efficient and easy to implement. Moreover, both horizontal and vertical component of confining pressure are considered in the 2D and 3D algorithms, which can ensure that the directions of confining pressure are always perpendicular to the specimen surfaces. Furthermore, the boundaries are continuous and closed in the new algorithms, which can prevent the escape of particles from the specimens. The effectiveness of the proposed algorithms is validated by biaxial and triaxial simulations of granular materials. The results show that the algorithms allow the boundaries to deform non-uniformly on the premise of maintaining high control accuracy of confining pressure. Meanwhile, the influences of different lateral boundary conditions on the numerical results are discussed. It is indicated that the flexible boundary is more appropriate for the models with large strain or significant localization than rigid boundary.

Flood Risk Management for Weirs: Integrated Application of Artificial Intelligence and RESCON Modelling for Maintaining Reservoir Safety

  • Idrees, Muhammad Bilal;Kim, Dongwook;Lee, Jin-Young;Kim, Tae-Woong
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2020년도 학술발표회
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    • pp.167-167
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    • 2020
  • Annual sediment deposition in reservoirs behind weirs poses flood risk, while its accurate prediction remains a challenge. Sediment management by hydraulic flushing is an effective method to maintain reservoir storage. In this study, an integrated approach to predict sediment inflow and sediment flushing simulation in reservoirs is presented. The annual sediment inflow prediction was carried out with Artificial Neural Networks (ANN) modelling. RESCON model was applied for quantification of sediment flushing feasibility criteria. The integrated approach was applied on Sangju Weir and also on estuary of Nakdong River (NREB). The mean annual sediment inflow predicted at Sangju Weir and NREB was 400,000 ㎥ and 170,000 ㎥, respectively. The sediment characteristics gathered were used to setup RESCON model and sediment balance ratio (SBR) and long term capacity ratio (LTCR) were used as flushing efficiency indicators. For Sangju Weir, the flushing discharge, Qf = 140 ㎥/s with a drawdown of 5 m, and flushing duration, Tf = 10 days was necessary for efficient flushing. At NREB site, the parameters for efficient flushing were Qf = 80 ㎥/s, Tf = 5 days, N = 1, Elf = 2.24 m. The hydraulic flushing was concluded feasible for sediment management at both Sangju Weir and NREB.

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