• Title/Summary/Keyword: Pipe Cooling

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Proposal of residual stress mitigation in nuclear safety-related austenitic stainless steel TP304 pipe bended by local induction heating process via elastic-plastic finite element analysis

  • Kim, Jong-Sung;Kim, Kyoung-Soo;Oh, Young-Jin;Oh, Chang-Young
    • Nuclear Engineering and Technology
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    • v.51 no.5
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    • pp.1451-1469
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    • 2019
  • This paper proposes a residual stress mitigation of a nuclear safety-related austenitic stainless steel TP304 pipe bended by local induction heating process via performing elastic-plastic finite element analysis. Residual stress distributions of the pipe bend were calculated by performing finite element analysis. Validity of the finite element analysis procedure was verified via comparing with temperature histories measured by using thermocouples, ultrasonic thickness measurement results, and residual stress measurement results by a hole-drilling method. Parametric finite element stress analysis was performed to investigate effects of the process and geometric shape variables on the residual stresses on inner surfaces of the pipe by applying the verified procedure. As a result of the parametric analysis, it was found that it is difficult to considerably reduce the inner surface residual stresses by changing the existing process and geometric shape variables. So, in order to mitigate the residual stresses, effect of an additional process such as cooling after the bending on the residual stresses was investigated. Finally, it was identified that the additional heating after the bending can significantly reduce the residual stresses while other variables have insignificant effect.

Effect of Pressurization and Cooling Rate on Dissolution of a Stationary Supercooled Aqueous Solution (정지상태 수용액에서 가압과 냉각속도가 과냉각해소에 미치는 영향)

  • Kim, Byung-Seon;Peck, Jong-Hyun;Hong, Hi-Ki;Kang, Chae-Dong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.12
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    • pp.850-856
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    • 2007
  • In a supercooled or capsule type ice storage system, aqueous solution (or water) may have trouble with non-uniform dissolution though the system contributes to the simplicity of system and ecological improvement. The non-uniform dissolution increases the instability of the system because it may cause an ice blockage in pipe or cooling part. In order to observe the supercooled state, a cooling experiment was performed with pressurization to an ethylene glycol(EG) 3 mass% solution in stationary state. Also, the effect of the pressurization from 101 to 505 kPa to the dissolution of supercooled aqueous solution was measured with the dissolution time of the supercooled aqueous solution at a fixed cooling rate of brine. At results, the dissolution of supercooled point decreased as the pressure of the aqueous solution in the vessel increased. Moreover, the dissolution point increased as the heat flux for cooling increased.

A study on flow characteristic of a stand type Kimchi refrigerator for optimum design of air flow passage (서랍식 김치냉장고의 최적 유로 설계를 위한 유동특성에 관한 연구)

  • Han, H.R.;Jung, H.Y.;Park, Y.K.;Choi, Y.H.;Lee, Y.W.
    • Journal of Power System Engineering
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    • v.15 no.5
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    • pp.37-42
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    • 2011
  • The normal cooling system of a refrigerator is applied to indirect a cooling methods. But the Kimchi refrigerator is applied to direct the cooling method. Recently when the model was applied to both direct and indirect the cooling methods, the improvement was considerable. With the development of the living standards in Korea, there has been more sensitive dissatisfaction about the taste and the smell of Kimchi. In order to solve these kinds, there is a need to systematic and scientific approach. Based on these, the purpose of this study is to optimize design for improve the storage period of Kimchi refrigerator. In this research, we concentrate on the temperature change and heat transfer characteristics of interior parts of the Kimchi refrigerator due to control cycle of temperature and flow phenomenon of cooling air.

Optimization of Plain Jacked Vessel Design in Adhesive Production Process Using Computational Fluid Dynamics (Computational Fluid Dynamics를 활용한 점/접착 생산 공정 내 Jacketed Vessel 설계 최적화)

  • Joo, Chonghyo;Park, Hyundo;Cho, Hyungtae;Kim, Junghwan
    • Applied Chemistry for Engineering
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    • v.31 no.6
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    • pp.596-602
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    • 2020
  • Blending process of adhesive production has a cooling process to cool down the temperature of the solution which was heated up to 76 ℃ with a mineral insulated (MI) cable by 30 ℃ at room temperature. Using a MI cable in the adhesive production process makes the production inefficient because it takes about 10 h for the cooling process. If a jacketed vessel is used instead of the MI cable, it would shorten the cooling downtime without any additional cooling system by using cold water. However, there are various types of jacketed vessels, and thus the most suitable type should be found before set up. In this study, we designed the optimized jacketed vessel for the adhesive production process by calculating the cooling downtime, which impacts production efficiency, as a function of the jacket types using computational fluid dynamics. As a result, the cooling performance of the plain jacket was 32.7% superior to that of the half-pipe coil jacket with the same height. In addition, the plain jacket with 60% spiral baffle reduced the cooling downtime and operating time by 80.4% and 25.1%, respectively.

Development of a Simplified Design Method for LBB Application to Nuclear Piping (원전 배관의 LBB 개념 적용을 위한 간략 설계기법 개발)

  • 허남수;이철형;김영진;석창성;표창률
    • Journal of the Korean Society of Safety
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    • v.14 no.2
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    • pp.32-41
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    • 1999
  • If the Leak-Before-Break (LBB) concept is applicable to the nuclear piping design, it is not necessary to consider the dynamic effect due to pipe rupture. Therefore, the construction cost can be significantly reduced by eliminating unnecessary pipe whip restraints and jet impingement devices. The objective of this paper is to develop the Piping Evaluation Diagram (PED) for efficient application of LBB concept to piping system at an initial piping design stage. For this purpose, the 3-D finite element analyses were performed to evaluate the crack stability. And the stress-strain curve based on the pipe material tests were used to calculate the detectable leakage crack length. Finally, the present PED which was composed as a function of NOP load and allowable SSE load, was developed for an application of LBB concept to the safety injection and shutdown cooling line in Korean Next Generation Reactor (KNGR).

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Analysis of Production Process Improvement with Life Cycle Assessment $Technology{\sim}$ Example of HDPE Pipe Manufacturing

  • Tien, Shiaw-Wen;Chiu, Chung-Ching;Chung, Yi-Chan;Tsai, Chih-Hung;Chang, Chin-Fa
    • International Journal of Quality Innovation
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    • v.8 no.2
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    • pp.32-56
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    • 2007
  • Life Cycle Assessment (LCA) aims to analyze possible impact upon manufacturing process and availability of products, and also study the environmental considerations and potential influence during entire life cycle ranging from procurement, production and utilization to treatment (namely, from cradle to tomb). Based on high-density polyethylene (HDPE) pipe manufacturing of company A, this case study would involve evaluation of environmental influence during the production process. When the manufacturing process has been improved during "production process" and "forming cooling" stage, it is found that capital input on "electric power" and "water supply" could be reduced, thus helping to sharpen the competitive power of company A, and also ensure sustainable economic and industrial development in accordance with national policies on environmental protection.

Development and Revenue Service of Propulsion System Using Integrated Stack(PEM) and Heat Pipe (일체형 스택(PEM) 및 냉각장치를 적용한 전동차 추진제어장치 개발 및 상용화)

  • Gim, Myung-Han;Lee, Gwang-Guk;Park, Su-Yong
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.680-685
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    • 2007
  • Power semiconductor which is adapted in the rolling stock has a high practicality for capacity of high voltage and high speed switching. but it has a trouble of fever cause of high speed On, Off switching loss and the operating junction temperature is limited to $150^{/circ}C$ because is made from the silicon for the foundation material. Therefore, it is important to find a way out of this trouble and must make the countermeasure. In this research, the caloric value of the integrated PEM is calculated to adapt the optimized heat pipe and the reliability of the heat pipe is demonstrated through the cooling performance test and vibration test.

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Analysis of Residual Stresses for the Multipass Welds of 316L Stainless Steel Pipe by Neutron Diffraction Method (중성자 회절법에 의한 316L 스테인리스강 배관 다층용접부의 잔류응력 해석)

  • 김석훈;이재한
    • Journal of Welding and Joining
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    • v.21 no.6
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    • pp.64-70
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    • 2003
  • Multipass welds of the 316L stainless steel have been widely employed in the pipes of Liquid Metal Reactor. Owing to localized heating and subsequent rapid cooling by the welding process, the residual stress arises in the weld of the pipe. In this study, the residual stresses in the 316L stainless steel pipe welds were calculated by the finite element method using ANSYS code. Also, the residual stresses both on the surface and in the interior of the thickness were measured by HRPD(High Resolution Powder Diffractometer) instrumented in HANARO Reactor. The experimental data and the calculated results were compared and the characteristics of the distribution of the residual stress discussed.

A Study on the Manufacturing Process for High-finned Tube of Copper Pipe using Roll Forming Method (전조공법을 이용한 동관의 하이핀 튜브 제조 공정에 대한 연구)

  • Kim, Tae-Gyu
    • Korean Journal of Materials Research
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    • v.16 no.2
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    • pp.111-115
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    • 2006
  • High-finned tubes have good thermal conductivity and have better cooling efficiency than plain tubes or low-fined tubes due to bigger air contact area. During high-fined tubes are manufactured by roll forming, the main technique is illustrated to optimizing primary material(copper pipe), optimized die matrix designing technique for roll forming, control manufacturing speed to develop productivity etc. In this study, a roll forming system was developed in oder to produce high-finned tube. Also a multi-step roll forming die was designed & built to produce high-finned tube that has over 10 mm fin height. And then, roll forming test using copper pipe was performed to produce high-finned tube. Roll forming process for producing highfinned tube was optimized by analyzing and adjusting misrostructure, hardness, and surface roughness of roll formed high-fined tube.

Analysis on the thermal development of radiatively participating pipe flow with nonaxisymmetric convective heat loss (비축대칭 대류열손실 경계조건하에서 원관내 복사에 관여하는 매질의 층류 열적 발달의 수치해석)

  • ;;Baek, Seung-Wook
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.11
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    • pp.2995-3002
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    • 1995
  • The cooling problem of the hot internal pipe flow has been investigated. Simultaneous conduction, convection, and radiation were considered with azimuthally varying convective heat loss at the pipe wall. A complex, nonlinear integro-differential radiative transfer equation was solved by the discrete ordinates method (or called S$_{N}$ method). The energy equation was solved by control volume based finite difference technique. A parametric study was performed by varying the conduction-to-radiation parameter, optical thickness, and scattering albedo. The results have shown that initially the radiatively active medium could be more efficiently cooled down compared with the cases otherwise. But even for the case with dominant radiation, as the medium temperature was lowered, the contribution of conduction became to exceed that of radiation.n.