In this study, in order to manufacture STS 316L seamless pipes with 18mm, 25mm, and 42mm diameters that can be used for high pressure, we intend to make predictions through design and finite element analysis and produce real objects. It was measured to have the highest hardness value in the deformed part, and it is expected to be due to work hardening. It has been interpreted that plastic deformation does not occur up to 1,000bar for STS 316L seamless pipes with a diameter of 18mm and 25mm, but plastic deformation occurs at 900bar or more in STS 316L seamless pipes with a diameter of 42mm.

본 논문에서는 배관의 ISO 도면 교환파일을 이용하여 AR/VR모델을 실시간으로 생성하는 방법을 소개한다. 도면 교환 파일 중에서 산업 표준으로 활용되는 IDF 파일을 분석했으며, 속성 정보의 추출과 함께 형상을 파라메트릭한 방법으로 정의하는 방법을 사용하였다. 이 방법을 통해서 파일 크기가 작은 도면 교환 파일을 사용함으로써 원거리 데이터 교환이 용이하면서도 형상과 속성을 모두 전달 할 수 있는 효과를 가질 수가 있다. 이 과정에서 본 논문에서는 배관과 컴포넌트의 형상을 템플릿 형태로 정의해 놓았으며, 이를 통해 배관의 도면 교환 파일로부터 실시간으로 배관 형상을 생성함과 동시에 설계 정보와 함께 AR/VR모델로 가시화가 됨을 검증하였다.

본 연구에서는 LNG 추진선에서 배관의 파손으로 천연가스가 누출되었을 때 누출공의 크기별 플래시 화재, 과압, 복사열에 따 른 피해범위를 ALOHA(Areal Location of Hazardous Atmospheres)를 이용하여 산출했다. 그리고 민감도 분석을 위해 환경 변수(풍속, 대기온 도, 대기 안정도)와 공정 변수(배관 압력, 배관 길이)로 구분하여 다양한 시나리오별 피해영향범위를 분석했다. 그 결과 환경 변수에 따른 피해범위는 플래시 화재에 의한 피해범위가 가장 컸으며 다음으로 과압, 복사열 순서로 큰 피해범위를 나타냈다. 그리고 공정 변수에 따른 피해범위를 산출한 결과 배관의 압력과 길이, 누출공의 크기와 관계없이 플래시 화재에 의한 피해범위가 가장 컸으며, 환경 변수와 동일하게 과압, 복사열 순서로 높은 피해범위를 보였다. 또한 누출공의 크기가 클수록 환경 변수와 공정 변수가 피해범위에 큰 영향을 주었으며 제트 환재에 의한 피해범위는 환경 변수에 비해 공정 변수에 의한 피해범위가 더 큰 것을 알 수 있었다.

In actual seawater desalination plant, the pressure loss due to frictional force of pipe is about 3~5 bar. Also, the pressure loss at pipe connection about 1~3 bar. Therefore, the total pressure loss in the pipe is expected to be about 4~8 bar, which translates into 0.111 to 0.222 kWh/m3 of energy when converted into the Specific Energy Consumption(SEC). Reducing energy consumption is the most important factor in ensuring the economics of seawater desalination processes, but pressure loss in piping is often not considered in plant design. It is difficult to prevent pressure loss due to friction inside the pipe, but pressure loss at the pipe connection can be reduced by proper pipe design. In this study, seawater desalination plant piping analysis was performed using a commercial network program. The pressure loss and SEC for each case were calculated and compared by seawater desalination plant size.

This study is carried out to analyze the velocity distribution for each location and the uniformity index according to straight distance on exit side by changing the design factors of branch pipe connected to 180° circular mixing-tee using RSM(Reynolds Stress Model) turbulence model. As the results of the flow characteristics according to hydraulic diameter, the velocity profiles in the 90° sectional area are generally similar. In the 180° section, the maximum velocity point shows Y/D=0.7~0.8 after rapid increase of the flow velocity. In the result according to the distance away from inlet, the maximum velocity point in the 90° sectional area is located in outer side of the curved pipe as the distance away from inlet increases. In the 180° sectional area, the maximum velocity point is showed in Y/D=0.7~0.8 after the rapid increase of the flow velocity regardless of the variation of branched distance. In case of inclined angle, the maximum velocity point in the 90° sectional area is located in outer side of the curved pipe as the inclined angle increases. In the 180° sectional area, the maximum velocity point is observed in Y/D=0.8 regardless of the inclined angle. In addition, the uniformity index of flow velocity shows that it is stabilizing after approximately L/D=40 away from the end of the curved pipe regardless of the flow factors in the branch pipe.

This study analyzed how the installation of a pressure gauge in the indoor fire hydrant of an apartment building affected identifying pressurized water in the pipe, making it easier to conduct internal inspection on the fire suppression system, and ensuring reliability of fire suppression. The following are the study’s results: First, identifying pressurized water in the indoor firefighting pipe had a positive effect on the installation of a pressure gauge in the indoor fire hydrant. This implies that a higher level of identification of pressurized water in the indoor firefighting pipe had a positive impact on improving the installation and use of a pressure gauge in the indoor fire hydrant. Second, making it easier for the fire safety officer to inspect the fire suppression system had a positive effect on the installation of a pressure gauge in the indoor fire hydrant. This suggests that if it becomes easier for the apartment building’s stakeholder to conduct internal inspection or the firefighting facility manager to carry out inspection on the fire suppression system, it would have a positive effect on the installation of a pressure gauge in the indoor fire hydrant. Finally, ensuring reliability in fire suppression had a positive effect on the installation of a pressure gauge in the indoor fire hydrant. This implies that if it becomes easier to identify pressurized water in the indoor firefighting pipe, for the fire safety officer to conduct internal inspection, or for the firefighting facility manager to carry out inspection in accordance with the fire suppression system’s internal inspection requirements, it would increase reliability in fire suppression, making it more necessary to install a pressure gauge in the indoor fire hydrant.

최근 국내에서 발생한 경주지진 및 포항지진이 도심지 및 원자력발전소 주변에서 발생함에 따라 인근 주요 구조시스 템에 피해를 발생시킨 바 있다. 이에 따라, 본 연구는 원전 배관계통의 지진 거동 특성을 실험 및 해석적으로 규명하고, 이를 바탕으로 내진성능을 평가하는 연구를 수행하는 것을 목적으로 한다. 이를 위하여, 원전 배관계통을 대상으로 한 진동대 시험 결과를 바탕으로 배관 수치해석 모델을 수립하고 이를 시험 결과를 통하여 검증한다. 또한, 이러한 검증된 수치해석모델을 기반으로 배관계통의 내진성능을 평가한다. 수치해석 모델 검증 결과, 수립된 수치모델의 고유진동수, 감쇠비 및 변위 응답이 진동 대시험 결과와 유사한 것으로 나타났다. 이러한 검증된 수치모델을 바탕으로 평가된 내진성능 값은 기존 원전 배관의 내진성능 값의 범위와 비교적 유사한 값으로 평가되었다. 이는 설계기준지진을 크게 상회하는 값이지만, 원전 주요 기기 임을 감안할 때 추가적인 내진성능 상향이 확보되면 원전 지진 안전성 향상에 많은 기여를 할 수 있을 것으로 판단된다. 본 연구의 결과는 추후 원전 배관계통 내진성능평가를 위한 정량적인 자료로 활용이 가능할 것으로 판단된다.

Pipe for water supply is one of the important parts that supply water to home, factory and so on. Water leakage in pipe for water supply due to deterioration, ground sinking and earthquake leads to enormous economical loss. Therefore, pipe for water supply should be designed to satisfy the requirement of, for instance, structural stability and fatigue durability. The purpose of this study was to investigate the fatigue durability of flexible joint for relaxing the impact due to earthquake and ground sinking. For this purpose, flexible joint was simulated using dynamic characteristics and fatigue life. As the results, the problem of fatigue durability may occur when flexible joint and pipe for water supply are treated as rigid body in simulation. Thus it means that the role of packing in flexible joint is very important and packing should be designed as optimal conditions that are considered fatigue durability as well as waterproof.

The pipe for water supply is essential part among SOC (Social Overhead Capital) fields. Pipe for water supply is mainly damaged by deterioration of pipe, earthquake, ground sinking and so on. The leakage of water have been led to enormous economical loss in our country. The purpose of this study was to investigate the structural stability of flexible joint for relaxing impact due to earthquake and ground sinking. For this purpose, flexible joint was simulated using tensile load and internal pressure. As the results, flexible joint for structural stability was needed the tensile load of below 3 ton and internal pressure of below 60 kgf/cm2. However, it is considered that real flexible joint should be applied more high safety factor than that of simulation result because of combined stress.

The purpose of this study is to provide basic data for setting environmental design standards for domestic greenhouses. We conducted experiments on thermal environment measurement at two commercial greenhouses where hot water heating system is adopted. We analyzed heat transfer characteristics of hot water heating pipes and heat emission per unit length of heating pipes was presented. The average air temperature in two greenhouses was controlled to 16.3oC and 14.6oC during the experiment, respectively. The average water temperature in heating pipes was 52.3oC and 45.0oC, respectively. Experimental results showed that natural convection heat transfer coefficient of heating pipe surface was in the range of 5.71~7.49W/m2 oC. When the flow rate in heating pipe was 0.5m/s or more, temperature difference between hot water and pipe surface was not large. Based on this, overall heat transfer coefficient of heating pipe was derived as form of laminar natural convection heat transfer coefficient in the horizontal cylinder. By modifying the equation of overall heat transfer coefficient, a formula for calculating the heat emission per unit length of hot water heating pipe was developed, which uses pipe size and temperature difference between hot water and indoor air as input variables. The results of this study were compared with domestic and foreign data, and it was found to be closest to JGHA data. The data of NAAS, BALLS and ASHRAE were judged to be too large. Therefore, in order to set up environmental design standards for domestic greenhouses, it is necessary to fully examine those data through further experiments.

조선 및 해양플랜트 산업은 복합 및 대형화됨에 따라 유지보수 및 검사 시스템이 중요해지고 있다. 최근 작업자의 작업 이해도 향상과 효율을 높이기 위해 증강현실기반 유지보수 및 검사 시스템이 많이 주목받고 있는데, 증강되는 모델과 현실 정보 간의 정확한 정합이 이루어지지 않아 작업에 오히려 혼동을 초래하는 일이 자주 발생한다. 이를 위하여 실모델에 특정 이미지를 부착하는 마커 기반 증강현실 기술이 사용되었으나, 조선 및 해양플랜트 산업 특성상 마커의 훼손 가능성이 있으며, 카메라가 명확히 마커 전체를 검출할 수 있어야 하기 때문에 작업자와 마커 간의 충분한 공간을 필요로 한다. 본 연구에서는 이러한 기존 증강현실 시스템의 한계점을 극복하기 위하여 마커리스 기반 증강현실을 활용하여 조선 및 해양플랜트 산업에서 가장 많은 공정을 차지하고 있는 파이프 시스템을 대상으로 정확하게 실 모델을 인식하고 해당 모델에 가상 CAD모델을 정합하는 방법론에 대해 연구하였다. 본 시스템을 통해 현실 작업자의 자세와 제한적인 환경에 따른 증강모델의 비틀림 현상을 개선하고 작업 이해에 혼동을 주는 현상을 없앨 수 있을 것으로 기대된다.

In this study, velocity distribution characteristics by location and uniformity according to exit straight length in a 180° mixed pipes were numerically analyzed using RSM (Reynolds Stress Model) turbulent model by changing various flow parameters such as working fluids, inlet air velocity etc. As a result of it, the working fluids characteristics was highly indicated by the viscous force difference, the maximum velocity points according to main pipe’s inlet velocity were indicated when 90° sectional location was distributed at X/D=0.5~0.6 region and 180° sectional location was distributed at Y/D=0.5 region. And the flow characteristics according to branch pipe’s inlet velocity when 90° sectional location was distributed at X/D=0.4~0.6 region and 180° sectional location was distributed at Y/D=0.5 region. Based on the results that the most stable exit straight length in flow uniformity was indicated at L/D=25~30 region, 40D is suggested as the effective measurement distance in the straight pipe downstream curved pipe of mixed pipe.

The visual inspection device was developed for non-destructive test of piping from the inside. The developed components of the system can be classified as camera module, main body module named crawler module and system module. Because the system has driving part as electric motors, it can run not only the horizontal and vertical straight lines but also bend lines. The system has video processors, it can make it possible to display the video on the monitor and to save the video clips simultaneously. Several tests were performed to check the development objectives.

Desalination plants have been recently constructed in many parts of the world due to water scarcity caused by population growth, industrialization and climate change. Most seawater desalination plants are designed with a submarine pipeline for intake and discharge. Submarine pipelines are installed directly on the bottom of the water body if the bottom is sandy and flat. Intake is located on a low-energy shoreline with minimal exposure to beach erosion, heavy storms, typhoons, tsunamis, or strong underwater currents. Typically, HDPE (High Density Polyethylene) pipes are used in such a configuration. Submarine pipelines cause many problems when they are not properly designed; HDPE pipelines can be floated or exposed to strong currents and wind or tidal action. This study examines the optimal design method for the trench depth of pipeline, analysis of on-bottom stability and dilution of the concentrate based on the desalination plant conducted at the Pacific coast of Peru, Chilca. As a result of this study, the submarine pipeline should be trenched at least below 1.8 m. The same direction of pipeline with the main wind is a key factor to achieve economic stability. The concentrate should be discharged as much as high position to yield high dilution rate.