• Title/Summary/Keyword: Piping design system

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Conceptual design of cryomodules for RAON

  • Kim, Y.;Lee, M.K.;Kim, W.K.;Jang, H.M.;Choi, C.J.;Jo, Y.W.;Kim, H.J.;Jeon, D.
    • Progress in Superconductivity and Cryogenics
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    • v.16 no.3
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    • pp.15-20
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    • 2014
  • The heavy ion accelerator that will be built in Daejeon, Korea utilizes superconducting cavities operating in 2 K. The cavities are QWR (quarter wave resonator), HWR (half wave resonator), SSR1 (sing spoke resonator1) and SSR2. The main role of the cryomodule is supplying thermal insulation for cryogenic operation of the cavities and maintaining cavities' alignment. Thermal and structural consideration such as thermal load by heat leak and heat generation, cryogenic fluid management, thermal contraction, and so on. This paper describes detailed design considerations and current results have being done including thermal load estimation, cryogenic flow piping, pressure relief system, and so on.

COMPARISON OF THE FIRE SUPPRESSION PERFORMANCE OF HALON REPLACEMENT AGENTS

  • Kim, Andrew K.;Joseph Z. Su
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 1997.11a
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    • pp.542-549
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    • 1997
  • HFC-227ea and HCFC Blend A were evaluated using full-scale fire tests to obtain information on their fire suppression performance, drop-in capability, thermal decomposition products and physical behaviour of the agent such as its flow characteristics in the piping system. Also, full-scale tests were conducted with Halon 1301 to provide a basis for comparison. Halon 1301, at concentrations of 5% to 7.5%, showed effective total-flooding fire- extinguishing performance for all test scenarios. HFC-227ea, at a design concentration of 7.6% or higher, and HCFC Blend A, at a design concentration of 12%, extinguished all fires in the test facility, however, these agents produced higher concentrations of acid gases than Halon 1301. The quantity of the acid gases generated during fire suppression was dependent on agent concentration, agent discharge time, fire type and size as well as extinguishment time.

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DESIGN STUDY OF AN IHX SUPPORT STRUCTURE FOR A POOL-TYPE SODIUM-COOLED FAST REACTOR

  • Park, Chang-Gyu;Kim, Jong-Bum;Lee, Jae-Han
    • Nuclear Engineering and Technology
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    • v.41 no.10
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    • pp.1323-1332
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    • 2009
  • The IHX (Intermediate Heat eXchanger) for a pool-type SFR (Sodium-cooled Fast Reactor) system transfers heat from the primary high temperature sodium to the intermediate cold temperature sodium. The upper structure of the IHX is a coaxial structure designed to form a flow path for both the secondary high temperature and low temperature sodium. The coaxial structure of the IHX consists of a central downcomer and riser for the incoming and outgoing intermediate sodium, respectively. The IHX of a pool-type SFR is supported at the upper surface of the reactor head with an IHX support structure that connects the IHX riser cylinder to the reactor head. The reactor head is generally maintained at the low temperature regime, but the riser cylinder is exposed in the elevated temperature region. The resultant complicated temperature distribution of the co-axial structure including the IHX support structure may induce a severe thermal stress distribution. In this study, the structural feasibility of the current upper support structure concept is investigated through a preliminary stress analysis and an alternative design concept to accommodate the IHTS (Intermediate Heat Transport System) piping expansion loads and severe thermal stress is proposed. Through the structural analysis it is found that the alternative design concept is effective in reducing the thermal stress and acquiring structural integrity.

A Study on the Internal Flow Analysis of High-pressure Shut-off Valve for CNG Charging Station Piping System (CNG 충전소 배관시스템용 고압 차단밸브에 대한 내부 유동해석에 관한 연구)

  • Chin, Do-Hun
    • Journal of the Korean Society of Industry Convergence
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    • v.24 no.6_2
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    • pp.773-779
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    • 2021
  • CNG, which has recently been attracting attention as an alternative fuel in the transportation field to reduce emissions caused by global warming, is natural gas with abundant reserves and mainly composed of methane. Being in a gaseous state, natural gas requires the compression and liquefaction processes for transportation. Until now, general shut-off valves for liquid and gas piping have been developed in Korea, but there are few studies on shut-off valves for high pressures of about 200 bar. Currently, research on the flow analysis of valves is being actively conducted around the world. However, there are relatively many studies on large valves such as low-pressure valves or shipbuilding and marine, and the safety factor through structural analysis to check the structural integrity of the valve is checked at the design stage. Since it is necessary to have a fast response speed while minimizing pressure and speed loss due to flow change, basic research was conducted on the flow analysis of the valve to secure design data, and the numerical analysis was performed on high-pressure automatic shut-off valves applied to CNG refueling stations. After securing the basic valve shape through reverse engineering for advanced products, we compared the valve flow coefficient Cv coefficient with advanced products. As a result, it was found that the reverse engineering model was at the level of about 60%. However, we compared the Cv coefficient by modifying the reverse engineering model, and the result showed that it was improved to about 96%.

Recent Progress in Air Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2007 (설비공학 분야의 최근 연구 동향 : 2007년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Shin, Dong-Sin;Choi, Chang-Ho;Lee, Dae-Young;Kim, Seo-Young;Kwon, Yong-Il
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.12
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    • pp.844-861
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    • 2008
  • The papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during the year of 2007 have been reviewed. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro nano fluid, micropump and fuel cell. Traditional CFD was still popular and widely used in research and development. Studies about fans and pumps were performed in the field of fluid machinery. Characteristics of flow and fin shape optimization are studied in the field of piping system. (2) The research works on heat transfer have been reviewed in the field of heat transfer characteristics, heat exchangers, and desiccant cooling systems. The research on heat transfer characteristics includes thermal transport in pulse tubes, high temperature superconductors, ground heat exchangers, fuel cell stacks and ice slurry systems. For the heat 'exchangers, the research on pin-tube heat exchanger, plate heat exchanger, condensers and gas coolers has been cordially implemented. The research works on heat transfer augmenting tubes have been also reported. For the desiccant cooling systems, the studies on the design and operating conditions for desiccant rotors as well as performance index are noticeable. (3) In the field of refrigeration, many papers were presented on the air conditioning system using CO2 as a refrigerant. The issues on the two-stage compression, the oil selection, and the appropriate oil charge were treated. The subjects of alternative refrigerants were also studied steadily. Hydrocarbons, DME and their mixtures were considered and various heat transfer correlations were proposed. (4) Research papers have been reviewed in the field of building facilities by grouping into the researches on heat and cold sources, air conditioning and air cleaning, ventilation and fire research including tunnel ventilation, flow control of piping system, and sound research with drain system. Main focuses have been addressed to the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies were mostly focused on analyzing the indoor environment in various spaces like cars, old tombs, machine rooms, and etc. in an architectural environmental field. Moreover, subjects of various fields such as the evaluation of noise, thermal environment, indoor air quality and development of energy analysis program were researched by various methods of survey, simulation, and field experiment.

Flow Safety Assessment by CFD Analysis in One-Touch Insertion Type Pipe Joint for Refrigerant (CFD 해석을 이용한 냉매용 원터치 삽입식 파이프 조인트의 유동 안전성 평가)

  • Kim, Eun-young;Park, Dong-sam
    • Journal of the Society of Disaster Information
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    • v.18 no.3
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    • pp.550-559
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    • 2022
  • Purpose: Pipes are widely used as applied devices in many industrial fields such as machinery, electronics, electricity, and plants, and are also widely used in safety-related fields such as firefighting and chemistry. With the diversification of products, the importance of technology in the piping field is also increasing. In particular, when changing the existing copper pipe to stainless steel, it is necessary to evaluate safety and flow characteristics through structural analysis or flow analysis. Method: This study investigated the safety by flow analysis of the 6.35 inch socket model, which are integrated insert type connectors developed by a company, using CFD analysis technique. For CDF analysis, RAN model and LES model are used. Result: As results of the analysis, amplitude of the pressure fluctuation acting on the wall of the piping system is formed at a level of 3,780 Pa or less, which is a very small level of pressure compared with the operating pressure or design stress of the refrigerant piping. Conclusion: These results mean that the effect of vibration caused by turbulence on the structural safety of the pipe is negligible.

Selection of Valves Susceptible to Pressure Locking and Thermal Binding (압력잠김 및 열고착 현상 발생가능 밸브의 선정)

  • Lee, Sung-No;An, Jin-Geun;Kim, Seoug-Beom
    • The KSFM Journal of Fluid Machinery
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    • v.10 no.5
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    • pp.20-26
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    • 2007
  • Some gate valves are susceptible to pressure locking and thermal binding which prevent the safety function. The safety related gate valves susceptible to pressure locking and thermal binding shall be identified and taken preventive actions to ensure the safety function. The identification of the gate valves susceptible to pressure locking and thermal binding needs the evaluation of system design, valve and piping arrangement, test requirements, and operating conditions. Application of preventive methods should consider the system safety function, applicability, effectiveness, interface with system design, and cost. The selection procedure of valves susceptible to pressure locking and thermal binding can be effectively used in industry including nuclear power plants. In order to prevent the pressure locking, the hole can be drilled through the one disc of upstream side or down stream and the external equalizing line can be installed from bonnet to downstream or upstream. The double disc parallel seat valve type can be used instead of flexible wedge gate valve to prevent the thermal binding. The identification of gate valves susceptible to pressure locking and thermal binding, and preventive actions will meet the regulatory requirements and enhance the availability and safety of plants.

Design and Implementation of Set-Top Box Software for Data Carousel (데이터 캐루셀을 위한 셋탑 박스 내부의 소프트웨어 설계 및 구현)

  • Kim, Min-Geun;Lee, Soo-Hyeong;Cheon, Kyung-Wook;Kim, Soo-Yeon;Yi, Yung;Kwon, Jae-Kwang;Choi, Sun-Kyu;Choi, Yang-Hee
    • Proceedings of the Korean Information Science Society Conference
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    • 1998.10a
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    • pp.577-579
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    • 1998
  • 지상파, 케이블, 위성 등의 기존 방송망을 이용하여, 사용자의 부합하는 데이터를 전송하는 데이터 방송 기법에 대한 연구와 표준화 작업이 활발하게 진행 중이다. 우리나라의 경우, 무궁화 위성을 이용한 부가 데이터 방송을 구현하고자 연구중이다. 데이터 방송시 데이터 전송 기법에는 데이터 스트리인(data streaming). 데이터 파이핑(data piping),데이터 캐루셀(data carousel)등이 제안되고 있다. 본 논문에서는 표준화 단체인 DVB에서 정의하고 있는 데이터 전송 기법에 대한 소개와, 함께, 데이터 캐루셀을 이용한 데이터 방송 구현에 필요한 소프트웨어 설계와 실제 구현에 관한 내용을 담고 있다.

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Equivalent Mechanical Property for Stress Analysis on Lined Pipe (Lined Pipe의 응력해석을 위한 등가 물성치 계산)

  • Choe, Jae-Seung;Jeong, Jin-Han
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.3
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    • pp.445-451
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    • 2002
  • The refractory-lined pipe is used to protect the system from high-temperature of the internal flow. The property of the refractory has an effect upon the stress analysis for fluid catalytic cracking(FCC) unit piping design. The equivalent elastic modulus and density considering steel and refractory must be applied in the stress analysis of the system. In the research, the theoretical method to obtain the value of the equivalent property is introduced and then the parametric analysis is carried out to understand the characteristic of the material properties, and the stress analysis is performed with reactor, the part of FCC unit.

IMPROVED POD METHODOLOGY USING MONTE CARLO SIMULATION

  • Park, Ik-Keun;Yoon, Jong-Hak;Ro, Sing-Nam;Seo, Seong-Won;Namkoong, Chai-Kwan
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.73-78
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    • 2003
  • Ultrasonic measurement is one of important technologies in the lift-time maintenance of nuclear poler plant. Ultrasonic inspection system is consisted of the operator, equipment and procedure. The reliability of ultrasonic inspection system is affected by its ability. The performance demonstration round robin was conducted to quantify the capability of ultrasonic inspection for in-service. The small number of teams who employed procedures that met or exceeded ASME Sec. XI Code requirements detected the piping of nuclear power plant with various cracks to evaluate the capability of detection and sizing. In this paper, the statistical reliability assessment of ultrasonic nondestructive inspection data using Monte Carlo simulation is presented. The results of the probability of detection (POD) analysis using Monte Carlo simulation are compared to these of logistic probability model. In these results, Monte Carlo simulation was found to be very useful to the reliability assessment f3r the small hit/miss data sets.

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