KR19990011121A - Mitigation method of thermal stratification in piping member with thermal stratification - Google Patents
Mitigation method of thermal stratification in piping member with thermal stratification Download PDFInfo
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- KR19990011121A KR19990011121A KR1019970034089A KR19970034089A KR19990011121A KR 19990011121 A KR19990011121 A KR 19990011121A KR 1019970034089 A KR1019970034089 A KR 1019970034089A KR 19970034089 A KR19970034089 A KR 19970034089A KR 19990011121 A KR19990011121 A KR 19990011121A
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- piping member
- heating
- thermal layer
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B1/00—Methods of steam generation characterised by form of heating method
- F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
- F22B1/023—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers with heating tubes, for nuclear reactors as far as they are not classified, according to a specified heating fluid, in another group
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C15/00—Cooling arrangements within the pressure vessel containing the core; Selection of specific coolants
- G21C15/24—Promoting flow of the coolant
- G21C15/257—Promoting flow of the coolant using heat-pipes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- General Engineering & Computer Science (AREA)
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- High Energy & Nuclear Physics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- Rigid Pipes And Flexible Pipes (AREA)
- Thermal Insulation (AREA)
Abstract
열성층이 발생되는 배관부재를 가열수단으로 가열하여 저온과 고온의 유체 온도차를 감소시킴으로써 열성층 완화에 따른 배관부재의 열적특성을 안정화시켜 열응력과 굽힘 현상을 감소시킬 수 있도록 하는 열성층이 형성되는 배관부재에서의 열성층 완화 방법을 제공하기 위한 것이다. 주곱수 계통의 배관부제 및 원자로 냉각재 계통과 연결된 수평 배관부재에서 고온 유체와 저온 유체가 함께 흐를 때 유체 밀도에 의해 형성되는 열성층을 완화시키는 것에 있어서, 상기 저온 유체가 흐르는 배관부재와 바깥 아래 부분을 가열수단으로 가열하여 성층화된 저온 유체를 가열함으로써 고온 유체와의 온도차가 줄어 성층화 현상을 완화시키는 것을 특징으로 한다.The thermal layer is formed to reduce the thermal stress and bending by stabilizing the thermal characteristics of the piping member by reducing the thermal layer by reducing the fluid temperature difference between low temperature and high temperature by heating the piping member where the thermal layer is generated by heating means. It is to provide a thermal layer mitigation method in the piping member. In mitigating the thermal layer formed by the fluid density when the hot fluid and the cold fluid flow together in the horizontal pipe member connected to the main product piping and the reactor coolant system, Heating the stratified low temperature fluid by heating means to reduce the temperature difference with the high temperature fluid to reduce the stratification phenomenon.
Description
본 발명은 배관계통에 저온과 고온의 액체가 함께 흐르면서 발생되는 열성층(thermal stratification)에 있어 저온의 액체를 가열시킴으로써 열성층을 완화시켜 배관부재의 열응력과 굽힘 현상을 감소시킬 수 있도록 하는 열성층이 형성되는 배관부재에서의 열성층 완화 방법에 관한 것이다.The present invention is a thermal stratification caused by the flow of low-temperature and high-temperature liquid in the piping system (thermal stratification) by heating the low-temperature liquid to relieve the thermal layer to reduce the thermal stress and bending of the piping member It relates to a thermal layer alleviation method in a piping member in which a layer is formed.
중력장에서 비회전 유체가 쉽게 혼합되지 않으면서 유체 밀도가 수직으로 변하고 수평면에서는 일정하게 층을 이루는 유체형태를 성층현상(stratified system)이라 한다.In the gravitational field, a fluid form in which the non-rotating fluid is not easily mixed but the fluid density changes vertically and is uniformly layered in the horizontal plane is called a stratified system.
밀도분포가 안정되어 있지 않은 경우에는 밀도차에 의한 자연대류 유동이 중요하고, 성층화 현상이 안정되어 있으면 두 층 사이에서의 혼합현상이 중요하다.If the density distribution is not stable, natural convection flow due to density difference is important, and if the stratification phenomenon is stable, mixing between two layers is important.
그런데 발전소(예로, 원자력 발전소)에서 시운전을 위한 가열이나 고온대기 운전과 같은 과도상태시 주급수 배관계통 및 원자로냉각제 계통과 연결된 수평배관에서 고온유체와 저온유체가 층을 이루어 혼합되지 않는 경우가 발생하게 되는데, 이를 열성층(thermal stratification)현상이라 한다.However, in a power plant (for example, nuclear power plant), hot fluid and cold fluid are not layered and mixed in a horizontal pipe connected to the main water supply pipe and the reactor coolant system during a transient state such as heating for commissioning or high temperature air operation. This is called thermal stratification.
이러한 배관에서의 현상에 의해 배관에는 열응력이 발생하게 된다.The phenomenon in the pipe causes thermal stress to occur in the pipe.
상기와 같이 열성층에 의해 발생되는 열응력은 수평배관에 있어 저온 유체를 점유하는 부분에서 일어나게 되며, 이에 의해 배관에 균열 발생의 원인을 제공하게 되고, 배관의 불필요한 변위 생성 및 배관 서포트에 과하중을 발생시키는 주요 원인이 되고 있다.As described above, the thermal stress generated by the thermal layer occurs in the portion occupying the low temperature fluid in the horizontal pipe, thereby providing a cause of cracking in the pipe, generating unnecessary displacement of the pipe, and overloading the pipe support. It is the main cause of the generation.
본 발명은 상기와 같은 종래 기술의 문제점을 해결하기 위해 창안된것으로, 열성층이 발생되는 배관부재를 가열수단으로 가열하여 저온과 고온의 유체 온도차를 감소시킴으로써 열성층 완화에 따른 배관부재의 열적특성을 안정화시켜 열응력과 굽힘현상을 감소시킬 수 있도록 하는 열성층이 형성되는 배관부재에서의 열성층 완화 방법을 제공하는데 그 목적이 있다.The present invention has been made to solve the problems of the prior art as described above, by heating the piping member in which the thermal layer is generated by heating means to reduce the fluid temperature difference between the low temperature and high temperature thermal properties of the piping member according to the thermal layer relaxation It is an object of the present invention to provide a thermal layer relaxation method in a piping member in which a thermal layer is formed so as to stabilize thermal stress and bending phenomenon.
상기의 목적을 달성하기 위헤 본 발명은 주급수 계통의 배관부재 및 원자로 냉각재 계통과 연결된 수평 배관부재에서 고온유체와 저온유체가 함께 흐를 때 유체밀도에 의해 형성되는 열성층을 완화시키는 것에 있어서, 상기 저온유체가 흐르는 배관부재의 바깥 아래 부분을 가열수단으로 가열하여 성층화된 저온유체를 가열함으로써 고온유체와의 온도차가 줄어 성층화 현상을 완하시키는 것을 특징으로 한다.In order to achieve the above object, the present invention is to alleviate the thermal layer formed by the fluid density when the high-temperature fluid and the low-temperature fluid flows together in the horizontal piping member connected to the piping member of the main water supply system and the reactor coolant system, By heating the lower and lower parts of the piping member in which the low-temperature fluid flows by heating means to heat the stratified low-temperature fluid to reduce the temperature difference with the high-temperature fluid to reduce the stratification phenomenon.
도 1은 본 발명의 실시예로 도시된 원자력 발전소의 가압기 수평배관의 개략 구성도1 is a schematic configuration diagram of a pressurizer horizontal piping of a nuclear power plant shown in an embodiment of the present invention
도 2는 도 1의 수평배관의 단면도2 is a cross-sectional view of the horizontal pipe of FIG.
도 3 (a)는 본 발명의 가열장치가 없는 경우, 유체와 배관내면의 온도변화를 나타낸 온도분포 특성비교표Figure 3 (a) is a temperature distribution characteristic comparison table showing the temperature change of the fluid and the inner surface of the pipe in the absence of the heating device of the present invention
(b)는 본 발명의 가열장치가 설치된 경우, 유체와 배관내면의 온도변화를 나타낸 온도분포 특성비교표(b) is a temperature distribution characteristic comparison table showing the temperature change between the fluid and the inner surface of the pipe when the heating device of the present invention is installed.
* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings
10 : 가압기 20 : 수평배관10: pressurizer 20: horizontal piping
30 : 전기가열기 40 : 저온유체30: electric heater 40: low temperature fluid
50 : 고온유체 60 : 분리층50: high temperature fluid 60: separation layer
이하에서 본 발명의 바람직한 실시예를 첨부된 도면에 의거 상세히 설명하기로 한다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
도 1은 본 발명의 실시예로 도시된 원자력 발전소의 가압기 수평배관의 개략 구성도이고, 도 2는 도 1의 수평배관의 단면도를 도시한 것이다.1 is a schematic configuration diagram of a pressurizer horizontal pipe of the nuclear power plant shown in the embodiment of the present invention, Figure 2 is a cross-sectional view of the horizontal pipe of FIG.
도시된 바와같이 가압정수로형 원자력 발전소의 가압기(10)와 수평배관(20)이 연결된 것에 있어서, 상기 수평배관(20)의 바깥 아래 부분(π/2)(즉, 저온유체가 점유하고 있는 부분)에 전기가열기(30)의 가열수단을 설치하여 상기 전기가열기(30)의 열에 의해 수평배관(20)의 내부에 흐르는 저온유체(40)가 가열되어 고온유체(50)와의 열성층을 완화시키도록 구성한 것이다.As shown in the connection of the pressurizer 10 and the horizontal pipe 20 of the pressurized water purifier type nuclear power plant, the lower and lower portion of the horizontal pipe 20 (ie, occupied by low temperature fluid) The heating means of the electric heater 30 is installed in the portion) so that the low temperature fluid 40 flowing inside the horizontal pipe 20 is heated by the heat of the electric heater 30 to heat the thermal layer 50 with the high temperature fluid 50. It is configured to alleviate the problem.
상기와 같이 구성된 본 발명에 의하면 가압기(10)측에 약 232℃의 고온유채(50)가 약 66℃의 저온유체(40)로 채워져 있는 수평배관(20)의 상부로 천천히 유입되면, 고온유체(50)와 저온유체(40)는 밀도 차에 의해 수평배관(20) 내에서 도 2에 도시된 바와같이 고온의 유체(50))는 수평배관(20)의 상부를 점유하게 되고, 상대적으로 낮은 온도를 갖는 저온유체(40)는 수평배관(20)의 하부를 점유하게 되어 분리층(60)을 이루면서 분리되게 된다.According to the present invention configured as described above, when the hot oil rapeseed 50 at about 232 ° C. is slowly introduced into the upper portion of the horizontal pipe 20 filled with the low temperature fluid 40 at about 66 ° C. on the pressurizer 10 side, the high temperature fluid 50 and the low temperature fluid 40 in the horizontal pipe 20 due to the difference in the density of the hot fluid 50 as shown in Figure 2 occupies the upper portion of the horizontal pipe 20, and The low temperature fluid 40 having a low temperature occupies the lower portion of the horizontal pipe 20 to be separated while forming a separation layer 60.
상기와 같은 상태에서 수평배관(20)의 바깥 아래부분(π/2)을 20,000w/㎡의 전기가열기(30)로 약 35초 동안 가열함으로써 저온 유체(40)가 간접가열되고 저온유체(40)와 고온유체(50)의 사이의 온도차가 줄어들게 되어 열성층 현상이 완화 되는 것이다.In the above state, by heating the outer lower portion (π / 2) of the horizontal pipe 20 with the electric heater 30 of 20,000 w / m 2 for about 35 seconds, the low temperature fluid 40 is indirectly heated and the low temperature fluid ( 40) and the temperature difference between the high temperature fluid 50 is reduced and the thermal stratification phenomenon is alleviated.
이에 따른 상기의 조건의 경우 가열하지 않은 경우에 비해 수평배관(20)의 상, 하부 내벽의 온도 차이가 17.1% 감소되고, 내부의 고, 저온유체(50)(40)의 온도 차이가 22.5%가 감소되는 효과를 얻게 된다.Accordingly, in the above conditions, the temperature difference between the upper and lower inner walls of the horizontal pipe 20 is reduced by 17.1%, and the temperature difference between the high and low temperature fluids 50 and 40 is 22.5%. The effect is reduced.
이후 외부 가열을 중단하고 수평배관(20) 내 유체의 자연대류에 의하여 열성층 유동이 없어지기까지의 걸리는 시간은, 외부를 가열하지 않은 경우보다 열성층 유동이 약 25%빨리 없어지는 효과를 얻게 된다.Thereafter, the time required for the external layer to be stopped and the thermal layer flow disappears due to the natural convection of the fluid in the horizontal pipe 20 is about 25% faster than the external layer heating. do.
상기의 설명에서 가열수단을 전기가열기(30)로 한정하는 것이 아니며, 기타 다른 열원을 이용할 수도 있는 것이다. 또한 배관의 수평 경사도에 관계없이 열성층 현상이 발생되는 모든 배관부재에 상기와 같은 가열수단으로 저온유체를 가열하여 열성층을 완화시킬 수 있음은 물론이다.In the above description, the heating means is not limited to the electric heater 30, but other heat sources may be used. In addition, regardless of the horizontal inclination of the pipe can be alleviated the thermal layer by heating the low-temperature fluid to the heating means as described above to all the piping member that the thermal layer phenomenon occurs.
이상에서 설명한 바와같이 본 발명은 발전소 등의 배관 계통에서 저온 유체와 고온 유체가 밀도 차에 의해 열성층 현상이 발생되는 것을 저온 유체를 점유하는 배관의 바깥 부분을 가열수단에 의해 가열시킴으로써 배관을 가열하지 않는 경우에 비해 배관의 내벽 온도차이가 크게 감소되고, 또한 배관 내부의 고, 저온유체의 온도차이가 크게 감소됨에 따라 배관의 열응력에 의한 굽힘 변위의 감소효과를 가져오게 되어 배관의 균열 방지 및 내구성을 향상시키계 되며, 또한 배관의 외부 가열 중단 후 배관 내부 유체의 자연대류에 의해 열성층 유동현상이 없어지는 효과를 갖게 되는 것이다.As described above, the present invention heats the pipe by heating the outer portion of the pipe occupying the low temperature fluid by heating means that the thermal stratification phenomenon occurs due to the difference in density between the low temperature fluid and the high temperature fluid in the piping system such as a power plant. Compared to the case of not doing so, the temperature difference of the inner wall of the pipe is greatly reduced, and the temperature difference of the high and low temperature fluid inside the pipe is greatly reduced, thereby reducing the bending displacement caused by the thermal stress of the pipe. And it improves the durability, and also has the effect that the thermal layer flow phenomenon is eliminated by the natural convection of the fluid inside the pipe after the external heating stop of the pipe.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019970034089A KR100203325B1 (en) | 1997-07-21 | 1997-07-21 | Mitigating method of thermal stratification in pipe systems |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019970034089A KR100203325B1 (en) | 1997-07-21 | 1997-07-21 | Mitigating method of thermal stratification in pipe systems |
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| Publication Number | Publication Date |
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| KR19990011121A true KR19990011121A (en) | 1999-02-18 |
| KR100203325B1 KR100203325B1 (en) | 1999-06-15 |
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