• Title/Summary/Keyword: Large system

Search Result 16,666, Processing Time 0.04 seconds

Research on Performance of Large Rotor-type Heat Recovery Exchanger using CFD Analysis on Surface Corrugation (요철형상의 CFD 해석을 통한 대용량 로타형 폐열회수열교환기 성능에 관한 연구)

  • Kim, Dong-Gyu;Ha, Byeong-Yong;Kim, Kun-Oh;Kum, Jong-Soo;Jeong, Seok-Kwon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.24 no.12
    • /
    • pp.875-880
    • /
    • 2012
  • The field of the large volume heat exchanger for wasted heat recovery ventilation system is being expanded enormously seeing as the fact that the quantity of reducing energies are huge due to the large volume heat exchanger for wasted heat recovery system at large buildings and factories, which consume large amount of energies while it has been arising huge amount of losses in Korea because of the lack of technology. To develop large volume waste heat recovery heat exchanger, rotor type heat exchanger was simulated for the surface corrugation. Based on the simulation results produced $30,000m^3/h$ grade waste heat recovery, heat exchanger was performed for the actual experiment. In addition, performance tests exceed the capacity of a large waste heat recovery heat exchanger performance test methods proposed.

Development and Verification of Large Triaxial Testing System for Dynamic Properties of Granular Materials (조립재료 동적물성 산정을 위한 대형삼축압축시험장비 구축 및 검증)

  • Lee, Sung-Jin;Kim, Yun-Ki;Choo, Yun-Wook;Lee, Sei-Hyun;Kang, Tae-Ho
    • Journal of the Korean Geotechnical Society
    • /
    • v.26 no.12
    • /
    • pp.5-17
    • /
    • 2010
  • Coarse granular material is used as important fill material in most of large embankments such as railway, road, dam and so on. Therefore, the accurate design parameters of the coarse granular material are necessarily required in design and construction. The behavior of the coarse granular material was not well understood because of the lack of large testing equipment capable of coarse granular material. A large triaxial testing system was developed in this research, capable of large specimens of 500 mm, 300 mm and 150 mm in diameter. In the new large triaxial testing system, the load cell is installed inside the triaxial cell and axial displacement is measured locally on a specimen in order to improve control and measurement in small strain level. Urethane specimens of 300 mm and 50 mm in diameter were prepared. The large triaxial tests were performed on the 300 mm diameter urethane specimens while RC/TS and impact echo tests on the 50 mm diameter urethane specimens to verify this testing system. In this verification test results, we could ascertain the reasonable test results of the KRRI large triaxial testing system.

National Oil Pollution Response System : Current Issues and Policy Recommendation (우리나라 기름오염방제제도의 문제점과 개선방안)

  • 목진용
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.7 no.2
    • /
    • pp.105-121
    • /
    • 2001
  • After the Sea Prince oil spill accident in 1995, the korean government has taken a measure to establish an emergency response system and equip clean-up capacity against large spill, major contents of which are as follows: First, Korea Marine Pollution Response Corporation has been established as a non-government organization for recovery of spilled oil in order to improve private response capabilities. Second, clean-up equipments, such as large clean-up vessels and oil fences for the open sea operation has been expanded. Third, a national contingency plan on the large spill accidents has been established compliance with the provisions of Article 6 of the OPRC 1990. However, there exist some problems in the national response system, such as clearly roles definition between government and private agencies; propel amendment of the Marine Pollution Prevention Act to incorporate major contents of the OPRC 1990; and training and exercises of clean-up personnel. With the above problems in mind, this paper reviews the current issues on the national oil pollution response system and recommends policy-making to tackle to those problems.

  • PDF

The Study on Improved Disaster Management System in Case of Large-scale Mass Casualties (대규모 인명피해 발생에 따른 재난관리체계 개선 방안)

  • Yoo, Byungtae;Ko, Jae Wook
    • Journal of the Korean Society of Safety
    • /
    • v.30 no.2
    • /
    • pp.77-82
    • /
    • 2015
  • When accidents that relate to a large numbers of people occur, such as disasters involving group tours by ship or aircraft, or large-scale chemical leakages, it is very important to know the personal identification of victims and to determine their locations and status. It is true that there will be serious damage or injury to people who engaged especially when information does not transfer properly or people get inaccurate one. In this study, therefore, we analysed the disaster response management system for rescued people of the Sewo ferry sinking accident. Based on the analysis we proposed to improve the real-time disaster management system with ICT(Information & Communication Technology).

Fault Simulation and Analysis of Generator (발전기의 사고 시뮬레이션과 분석)

  • Park, Chul-Won;Oh, Yong-Taek
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.62 no.3
    • /
    • pp.151-158
    • /
    • 2013
  • Large generator of power plant is very important. In order to protect large generator from faults, digital protective relay or IED is required. However, all protective relays for generators of the domestic power plant are operated by foreign products. And now, for technological independence from foreign and improvement of import substitution effect, IEDs using domestic technology are being developed. To evaluate performance of developing next-generation power devices, the study of the dynamic characteristics of the power plant, generator system modeling, fault simulation and analysis, should be considered. Specially, To obtain IEEE Standards COMTRADE format for relay operation test, generator system modeling and fault simulation using PSCAD/EMTDC tools must be preceded. Until now, a complete modeling of generator internal windings and fault simulation techniques dose not exist. In this paper, for evaluation performance of relay elements of developing IED, the generator system modeling and various faults simulation using PSCAD/EMTDC tools were performed. And then, the various transient phenomena through obtained relaying signal of developed modeling were analyzed.

Parallel Fuzzy Inference Method for Large Volumes of Satellite Images

  • Lee, Sang-Gu
    • International Journal of Fuzzy Logic and Intelligent Systems
    • /
    • v.1 no.1
    • /
    • pp.119-124
    • /
    • 2001
  • In this pattern recognition on the large volumes of remote sensing satellite images, the inference time is much increased. In the case of the remote sensing data [5] having 4 wavebands, the 778 training patterns are learned. Each land cover pattern is classified by using 159, 900 patterns including the trained patterns. For the fuzzy classification, the 778 fuzzy rules are generated. Each fuzzy rule has 4 fuzzy variables in the condition part. Therefore, high performance parallel fuzzy inference system is needed. In this paper, we propose a novel parallel fuzzy inference system on T3E parallel computer. In this, fuzzy rules are distributed and executed simultaneously. The ONE_To_ALL algorithm is used to broadcast the fuzzy input to the all nodes. The results of the MIN/MAX operations are transferred to the output processor by the ALL_TO_ONE algorithm. By parallel processing of the fuzzy rules, the parallel fuzzy inference algorithm extracts match parallelism and achieves a good speed factor. This system can be used in a large expert system that ha many inference variables in the condition and the consequent part.

  • PDF

Web Catchphrase Improve System Employing Onomatopoeia and Large-Scale N-gram Corpus

  • Yamane, Hiroaki;Hagiwara, Masafumi
    • International Journal of Fuzzy Logic and Intelligent Systems
    • /
    • v.12 no.1
    • /
    • pp.94-100
    • /
    • 2012
  • In this paper, we propose a system which improves text catchphrases on the web using onomatopoeia and the Japanese Google N-grams. Onomatopoeia is regarded as a fundamental tool in daily communication for people. The proposed system inserts an onomatopoetic word into plain text catchphrases. Being based on a large catchphrase encyclopedia, the proposed system evaluates each catchphrase's candidates considering the words, structure and usage of onomatopoeia. That is, candidates are selected whether they contain onomatopoeia and they use specific catchphrase grammatical structures. Subjective experiments show that inserted onomatopoeia is effective for making attractive catchphrases.

An Effective Fault Analysis Method in Large Scale Power System (대전력계통의 고장해석에 관한 효추적인 계산방법에 관한 연구)

  • Jai-Kil Chung;Gi-Sig Byun
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.32 no.12
    • /
    • pp.435-440
    • /
    • 1983
  • The methods of forming the bus impedance matrix, which is mainly employed in fault analysis of power system, can be generally classified in catagories, (1) the one being the inverse matrix of bus admittance matrix, and (2) the other the bus impedance matrix succesive formation method by particular algorithms. The former method is theouetically elegant, but the formation and inverse of complex bus admittance matrix for large power system requires too much amounts of computer memory space and computing time. The latter method also requires too much memory space. Therefore, in this paper, an algorithm and computer program is introduced for the formation of a sparse bus impedance matrix which generates only the matching terms of the admittance matrix. So, this method can reduce the computer memory and computing time, and can be applied to fault analysis of large power system by small digital computer.

Validation of Flexible Rotor Model for a Large Capacity Flywheel Energy Storage System (유한요소법을 이용한 대용량 플라이휠 에너지 저장 장치의 연성 회전체 모델의 검증)

  • Yoo, Seong-Yeol;Park, Cheol-Hoon;Choi, Sang-Kyu;Lee, Jeong-Pil;Noh, Myoung-Gyu
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.32 no.12
    • /
    • pp.1096-1101
    • /
    • 2008
  • When we design a controller for the active magnetic bearings that support a large rotor, it is important to have an accurate model of the rotor. For the case of the flywheel that is used to store energy, an accurate rotor model is especially important because the dynamics change with respect to the running speed due to gyroscopic effects. In this paper, we present a procedure of obtaining an accurate rotor model of a large flywheel energy storage system using finite-element method. The model can predict the first and the second bending mode which match well with the experimental results obtained from a prototype flywheel energy storage system.

The analysis of inductive contactless inductive power transformer used for the PRT(Personal Rapid Transit) system (소형궤도 차량 시스템에 적합한 무접촉 유도 전력 변환 장치의 특성해석)

  • Han, K.H.;Lee, B.S.;Byun, Y.S.;Baek, S.H.
    • Proceedings of the KIEE Conference
    • /
    • 2004.10a
    • /
    • pp.218-220
    • /
    • 2004
  • In this paper, the concept of contactless inductive power transfer system used for the PRT system is suggested and some ideas for Power transformer design to improve the power transfer performance are presented. This system has a large air-gap and demands a large electrical power capability But, low output power is generated due to a loosely coupled characteristic of the large air-gap. Therefore, double layer construction of secondary winding, which was divided in half to increase both output current and output voltage was suggested. In addition, the performance of power transformer alignment condition between the primary power line and the power collector was verified by computer simulation of 2kW model.

  • PDF