• 제목/요약/키워드: Coiled tube

검색결과 40건 처리시간 0.03초

Steam generator performance improvements for integral small modular reactors

  • Ilyas, Muhammad;Aydogan, Fatih
    • Nuclear Engineering and Technology
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    • 제49권8호
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    • pp.1669-1679
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    • 2017
  • Background: Steam generator (SG) is one of the significant components in the nuclear steam supply system. A variety of SGs have been designed and used in nuclear reactor systems. Every SG has advantages and disadvantages. A brief account of some of the existing SG designs is presented in this study. A high surface to volume ratio of a SG is required in small modular reactors to occupy the least space. In this paper, performance improvement for SGs of integral small modular reactor is proposed. Aims/Methods: For this purpose, cross-grooved microfins have been incorporated on the inner surface of the helical tube to enhance heat transfer. The primary objective of this work is to investigate thermal-hydraulic behavior of the proposed improvements through modeling in RELAP5-3D. Results and Conclusions: The results are compared with helical-coiled SGs being used in IRIS (International Reactor Innovative and Secure). The results show that the tube length reduces up to 11.56% keeping thermal and hydraulic conditions fixed. In the case of fixed size, the steam outlet temperature increases from 590.1 K to 597.0 K and the capability of power transfer from primary to secondary also increases. However, these advantages are associated with some extra pressure drop, which has to be compensated.

코일형 흡수기에서 증기 유동 방향이 유하액막 열전달에 미치는 영향 (제1부: 물을 이용한 실험) (Effect of Vapor Flow Direction on Falling Film Heat Transfer in a Coiled Tube Absorber (Part 1: Experiments with Pure Water))

  • 박경진;권경민;정시영;김병주
    • 설비공학논문집
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    • 제13권8호
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    • pp.720-729
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    • 2001
  • The effect of vapor flow direction on falling film heat transfer was experimentally investigated by using water. Parallel flow (both water and vapor downwards) showed higher heat exchange performance than counterflow(downward water and upward vapor). The difference became significant as the vapor flow rate was increased. It is supposed that the uprising vapor disturbs the solution film flow and heat transfer is reduced by uneven distribution or detachment of water film.

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Liquid Based Solar Thermal Storage를 위한 열교환성능(熱交換性能)에 관한 연구(硏究) (A Study on the Heat Exchange Performance for the Liquid Based Solar Thermal Storage)

  • 김병철;정현채
    • 태양에너지
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    • 제5권2호
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    • pp.35-45
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    • 1985
  • A solar hot water storage tank was designed and constructed to examine the heat exchange performances on load side for the solar thermal storage in a single loop solar water heating system. In the tank helically coiled tube was immersed. The hot water was circulated from either top or bottom. The circulation flow rate was varied from 500 ml/min to 20,000 ml/min. The effect of flow rate was observed. The thermal performances according to the flow rate and flow direction were examined. The temperature distributions in the tank and inside of the tubes were plotted along the process of cooling.

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가스상 TCE 처리를 위한 추출막 생물반응기의 수학적 모사

  • 김지석;김관수;장덕진
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2000년도 춘계학술발표대회
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    • pp.370-373
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    • 2000
  • In this work, an extractive membrane bioreactor containing coulture broth of Burkholderia cepacia G4 PR1 constitutively expressing the TCE-degrading enzyme, tolune-ortho-monooxygenase(TOM), was used for the degradation of TCE. The membrane bioreactor operates by seperating the TCE-containing waste gas from the aerated biomedium, by which the air-stripping of TCE without degradation was overcome that could occur in conventional aerobic biological treatments of TCE-contaminated waste gases. This was achieved by a silicone rubber membrane which was coiled around a perspex draft tube. TCE from the gas phase diffuses across the silicone rubber membrane into microbial culture broth that was continuously fed from a separate aerobic CSTR. Therefore, TCE degradation occured without the TCE being directly exposed to the aerating gas stream. Of the TCE supplied to the membrane bioreactor, 72.6% was biodegraded during the operation of this system. To construct a mathematical model for this system, parameters describing microbial growth kinetics on TCE were determined using a CSTR bioreactor. Else parameters used for numerical simulation were determined from either indepedent experiments or values reported in the literature. The model was compared with the experimental data, and there was a good agreement between the predicted and the measured TCE concentrations in the system. To achieve a higher treatment efficiency, various operating conditions were simulated as well.

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세척이 가능한 원통 코일형 열교환기의 파울링 특성에 관한 연구 (Fouling Characteristics of Washable Shell and Coil Heat Exchanger)

  • 황준현;나병철;오세기;구경민;이재근;안영철
    • 설비공학논문집
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    • 제27권2호
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    • pp.69-74
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    • 2015
  • In this work, we studied the shell and helically coiled tube heat exchangers. Shell and coil heat exchangers with different rate of water flow and plate heat exchanger with same capacity were tested for condensing conditions. We proposed design guide using modified Wilson plot method. We compared fouling characteristics between shell and coil heat exchanger and plate heat exchanger, when they were washed and were not washed. The shell and coil heat exchanger showed 120% of higher saturated fouling resistance value and 4% of better heat transfer ratio than the plate heat exchanger.

광반응 HPLC를 이용한 시호 사포닌의 분석 (Analysis of Saikosaponins by HPLC with Photoreduction Fluorescence Detection)

  • 신영근;조경희;권수진;도영미;황귀서;박정일;박만기
    • 약학회지
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    • 제40권1호
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    • pp.41-45
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    • 1996
  • A high performance liquid chromatography using photoreduction fluorescence detection was described for the analysis of saikosaponins. Saikosaponins were separated on an $NH_2$ column using acetonitrile and aqueous 2-tert-butylanthraquinone(t-BAQ) as mobile phase. Column effluent was passed through a 40cm PTFE capillary tube coiled around a 10W UV lamp to reduce t-BAQ to a highly fluorescent dihydroxyanthracene derivative which was detected by a fluorescence detector. The optimal concentration of t-BAQ was found to be $6{\times}10^{-5}M$ and the optimal reaction time to be 2 seconds. The detection limit for saikosaponin a and d by this method was found to be about 280ng and 80ng. The dynamic linear range was over two orders and the correlation coefficient of the calibration curve of them was 0.998.

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고준위폐기물 심부시추공 처분을 위한 처분용기 접속장치의 개발 (Development of Novel Joint Device for a Disposal Canister in Deep Borehole Disposal)

  • 이민수;이종열;지성훈
    • 방사성폐기물학회지
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    • 제16권2호
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    • pp.261-270
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    • 2018
  • 심부시추공 처분에서 정치기구와 처분용기 사이를 연결하는'J-slot joint'를 대체할 수 있는 새로운 접속장치를 개발하고자 하였다. 새로운 접속장치는 처분용기 쪽의 쐐기와 이를 체결할 수 있는 정치기구 쪽의 쐐기집으로 구성되었다. 새로운 접속 장치는 부품교체 없이도 체결과 분리가 자유롭고, Drill pipe 외에도 Wire-line이나 Coiled tubing 등의 정치기구와도 연결이 가능한 장점을 갖추었다. 새로운 접속장치의 실증을 위해, 1/3 크기로 새로운 접속장치(${\Phi}110mm$, H 148 mm), 처분용기 2단 행렬(${\Phi}140mm$, H 1,105 mm), 그리고 모의 시험공(${\Phi}150mm$, H 1,500 mm)을 설계 및 제작하였다. 새로운 접속장치의 실증시험용 머드로는 Na형 벤토나이트(MX-80)와 Ca형 벤토나이트(GJ-II)를 고형분 함량 7wt% 및 29wt%로 각각 제조하여 사용하였다. 실증시험 결과, 새로운 접속장치는 벤토나이트 머드와 순수 조건에 대해 $10m{\cdot}min^{-1}$ 속도에서 무리없이 작동하였다. 결론적으로, 심부시추공 처분을 위한 새로운 처분용기 접속장치는 정치와 회수를 위한 접속장치로 향후 유용하게 활용될 수 있다고 보았다.

화학축열을 통한 태양열 저장을 위한 메탄의 스팀개질 반응 특성(Part 1. 메탄 전화율) (Steam Reforming of Methane for Chemical Heat Storage As a Solar Heat Storage. Part 1. Conversion of Methane)

  • 양동현;정찬화;한귀영;서태범;강용혁
    • 한국태양에너지학회 논문집
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    • 제21권3호
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    • pp.1-8
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    • 2001
  • 고온의 태양열을 저장하기 위한 한 방편으로 화학반응을 이용한 태양에너지의 화학에너지로의 변환공정을 고려하였다. 태양에너지의 저장은 메탄의 수증기 개질반응으로 선정하였으며, 이 흡열반응에서 메탄의 전화율 특성을 살펴보았다. 반응기는 직경, 6.25 mm, 그리고 길이 30 cm 인 stainless steel을 코일형태로 제작하였다. 반응온도 범위내에서 메탄의 전화율은 반응온도에 따라서 선형적으로 증가하였으며 반응온도 $500^{\circ}C{\sim}900^{\circ}C$ 범위에서 메탄의 전화율은 약 $60%{\sim}90%$ 로 측정되었다. 이 실험을 통하여 태양열 저장을 위한 메탄의 수증기 개질반응의 타당성을 확인하였다.

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나선코일의 열전달 특성에 관한 연구 (A Study on Heat Transfer Characteristics of Helical Coiled Tube)

  • 박종운;조동현
    • 수산해양교육연구
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    • 제16권2호
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    • pp.257-270
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    • 2004
  • The two-phase closed thermosyphon is a heat transfer device capable of transfer large quantities of heat from a source to a sink by taking advantage of the high heat transfer rates associated with the evaporation and condensation of a working fluid within the device. A study was carried out with the performance of the heat transfer of the thermosyphon having 50, 60, 70, 80, 90 internal micro grooves in which boiling and condensation occur. A plain thermosyphon having the same inner and outer diameter as the grooved thermosyphon is also tested for comparison. Water, methanol and ethanol have been used as the working fluids. The liquid filling as the ratio of working fluid volume to total volume of thermosyphon, the inclination angle, micro grooves and operating temperature have been used as the experimental parameters. The heat flux and the boiling and the condensation heat transfer coefficient and overall heat transfer coefficient at the condenser and evaporator zone are estimated from the experimental results. The experimental results have been assessed and compared with existing correlations. Imura's and Kusuda's correlation for boiling showed in good agreement with experimental results within ${\pm}20$% in plain thermosyphon. The maximum heat transfer rate was obtained when the liquid fill ratio was about 25%. The high heat transfer coefficient was found between 25o and 30o of inclination angle for water and between 20o and 25o for methanol and ethanol. The relatively high rates of heat transfer have been achieved in the thermosyphon with internal micro grooves. The micro grooved thermosyphon having 60 grooves shows the best heat transfer coefficient in both condensation and boiling. The maximum enhancement (i.e. the ratio of the heat transfer coefficients of the micro grooved thermosyphon to plain thermosyphon) is 2.5 for condensation and 2.3 for boiling.

관중숭불도에 나타난 16세기 복식연구 (A Study of Costumes in the Palace Painting Depicting the Worship of Buddha during the Reign of King Myungjong)

  • 홍나영;김소현
    • 복식
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    • 제38권
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    • pp.305-321
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    • 1998
  • The costume style of the Chosun dynasty changed greatly after Imjinwaeran (the Japanese Invasion of Chosun Korea, 1592∼1598). Most of the extant costumes come from the late Chosun, but some costumes produced be-fore Imjinwaeran have been excavated, and in addition, information on these older constumes is contained in contemporary literature. Of especial value in the study of pre-Imjinwaeran Chosun constumes is a mid-sixteenth century palace painting depicting the worship of Buddha, a painting in the collection of the Ho-Am Art Museum in Seoul. The present study of costume during the middle Chosun dynasty focuses on this painting, and compares it with other contemporary palace paintings, and with other contemporary palace paintings, and with Nectar Ritual Paintings. The following conclusion were drawn : * Concerning woman's hair styles of the time, married women wore a large wig. Un-married women braided their hair, and then either let it fall down their back or wore it coiled on top of their head. * The major characteristic of woman's costumes was a ample, tube-like silhouette, with the ratio of the Jeogori(Korean woman's jacket) and skirt being one-to-one. * The style of Jeogori in the painting was like that of excavated remains. Some Jeogoris were simple (without decoration), while some Jeogoris were worn with red sashes. Here we can confirm the continuity of ancient Korean costumes with those of the sixteenth century * Although the skirt covered the ankles, it did not touch the ground. Because the breadth of the skirt was not wide, it seems to have been for ordinary use. Colors of skirts were mainly white or light blue. * All men in the painting wore a headdress. Ordinary men, not Buddhist monks, wore Bok-du (headstring), Chorip (straw hat), or Heuk-rip (black hat). In this painting, men wore a Heukrip which had a round Mojeong (crown). * The men wore sashes fastened around their waist to close their coats, which was different from the late Chosun, in which men bound their sashes around their chest. That gave a ration of the bodice of the coat to the length of the skirt of one-to-one, which was consistent with that of woman's clothing. * In this painting, we cannot see the Buddhist monk's headdress that appeared later in the Chosun, such as Gokkal (peaked hat), Songnak (nun's hat), and Gamtu (horsehair cap). These kinds of headdresses, which appeared in paintings from the seventeenth century, were worn widely inside or outside the home. Buddhist monks wore a light blue long coat, called Jangsam (Buddhist monk's robe) and wore Gasa (Buddhist monk's cope), a kind of ceremonial wrap, round their body. We can see that the Gasa was very splendid in the early years of the Chosun dynasty, a continuing tradition of Buddhist monk's costumes from the Koryo dynasty.

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