• 연구논문집
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• s.32
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• pp.65-76
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• 2002

The intensity of x-ray or gamma-ray is attenuated according to density and thickness of the transmitted medium. In this study, by using this principle, on-line real-time radiometric system was developed using a 128 channels linear array of solid state detectors to measure wall thickness of insulated piping system. This system uses a Ir-192 as a gamma ray source and detector is composed of BGO scintillator and photodiode. Ir-192 gamma ray source and linear detector array mounted on a computer controlled robotic crawler. The Ir-192 gamma ray source is located on one side of the piping components and the detector array on the other side. The individual detectors of the detector array measure the intensity of the gamma rays after passing through the walls and the insulation of the piping component under measurement. The output of the detector array is amplified by amplifier and transmitted to the computer. This system collects and analyses the data from the detector array in real-time. The maximum measurable length of pipe is 120cm/mm. in the case of 1mm scanning interval.

• The KSFM Journal of Fluid Machinery
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• v.10 no.4
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• pp.55-60
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• 2007

This paper describes an evaluation method of pressure drop in a circular pipe of waste collection piping system. Accurate pressure drop in a piping system is very important to determine the capacity of turbo blower, which is one of the main elements in the system. Three-dimensional Navier-Stokes analysis is introduced to analyze the pressure drop in the piping system. Organic waste is selected and modeled using the result of site survey performed in an apartment area. Evaluation method of pressure drop used In the present numerical simulation is performed in the shortened pipe line prior to the calculation of the real system. Throughout the numerical simulation, pressure drop in a waste pipe is obtained and compared to the value determined by analytical method. The pressure drop obtained by numerical simulation has a good agreement with that of the analytic method. It is noted that present evaluation method is effective to determine a pressure drop in the piping system. Detailed flow characteristics inside the pipe line are also analyzed and discussed.

• Korean Journal of Computational Design and Engineering
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• v.17 no.4
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• pp.246-252
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• 2012

The piping route of hydraulic hose is designed with avoiding interferences to surrounding components. However, in a real practice, the piping route is mostly decided with an expert's experiences on site due to the complexity of design. Thus, this paper proposes a design methodology of the optimized route of a hose. We use NURBS representation to describe the piping route, which is possible to be locally modified, and an energy minimization method is applied to avoid interferences to the surroundings. In other words, the NURBS curve describing a piping route is modified to meet the desired positions from minimizing the perturbation of the control points, and the strain energy of the curve is then optimized to make the curve natural. The proposed method is implemented and its feasibility is validated using the commercial CAD software, CATIA V5.

• Tribology and Lubricants
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• v.30 no.2
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• pp.124-129
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• 2014

The piping system accounts for a large portion of the machinery structure of a plant, and is considered as a very important mechanical structure for plant safety. Accordingly, it is used in most energy plants in the nuclear, gas, and heavy chemical industries. In particular, the piping system for a nuclear plant is generally complicated and uses the reactor and its cooling system. The piping equipment is exposed to diverse loads such as weight, temperature, pressure, and seismic load from pipes and fluids, and is used to transfer steam, oil, and gas. In ultrasound infrared thermography, which is an active thermography technology, a 15-100 kHz ultrasound wave is applied to the subject, and the resulting heat from the defective parts is measured using a thermography camera. Because this technique can inspect a large area simultaneously and detect defects such as cracks and delamination in real time, it is used to detect defects in the new and renewable energy, car, and aerospace industries, and recently, in piping defect detection. In this study, ultrasound infrared thermography is used to detect information for the diagnosis of nuclear equipment and structures. Test specimens are prepared with piping materials for nuclear plants, and the optimally designed ultrasound horn and ultrasound vibration system is used to determine damages on nuclear plant piping and detect defects. Additionally, the detected images are used to improve the reliability of the surface and internal defect detection for nuclear piping materials, and their field applicability and reliability is verified.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.381-388
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• 2009

In some portions of nuclear piping systems, stratification phenomena may occur due to the density difference between hot and cold stream. When the temperature difference is large, the stratified flow under diverse operating conditions can produce high thermal stress, which leads to unanticipated piping integrity issues. The objectives of this research are to examine controvertible numerical factors such as model size, grid resolution, turbulent parameters, governing equation, inflow direction and pipe wall. Parametric three-dimensional computational fluid dynamics analyses were carried out to quantify effects of these parameters on the accuracy of temperature profiles in a typical nuclear piping with complex geometries. Then, as a key finding, it was recommended to use optimized mesh of real piping with the conjugated heat transfer condition for accurate thermal stratification analyses.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.2
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• pp.143-151
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• 2019

This study describes a method for analyzing log data generated in a process using process mining techniques. A system for collecting and analyzing a large amount of log data generated in the process of manufacturing an offshore plant piping material was constructed. The analyzed data was visualized through various methods. Through the analysis of the process model, it was evaluated whether the process performance was correctly input. Through the pattern analysis of the log data, it is possible to check beforehand whether the problem process occurred. In addition, we analyzed the process performance data of partner companies and identified the load of their processes. These data can be used as reference data for pipe production allocation. Real-time decision-making is required to cope with the various variances that arise in offshore plant production. To do this, we have built a system that can analyze the log data of real - time system and make decisions.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.1
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• pp.19-24
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• 2021

This paper presents a method to generate three-dimensional AR/VR models using the information in Isogen data files (IDFs). An IDF is an output file produced by ISOGEN that contains piping isometric drawings. A piping isometric drawing is used for pipeline installation in the shipyard; therefore, the drawing describes assembly information with symbolic features, not with detailed geometric features. An IDF specifies relationships between piping routes and components with three-dimensional points and tag information as well as the bill of the materials of a pipeline. The key idea of this paper is that AR/VR models can be generated with the piping route points data and piping components tag information in real time, without any conversion of standard data exchange file formats, such as STP, IGES, and SAT. This paper describes IDF data structure and suggests the geometry generation process with IDF data and parametric functions.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.10
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• pp.1011-1016
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• 2015

Gas piping systems in power plants and factories are always influenced by the mechanical vibrations of rotational machines such as pumps, blowers, and compressors. Unusual vibrations in a gas piping system influence possible leakages of liquids or gases, which can lead to large explosive accidents. Real-time measurements of unusual vibrations in piping systems in situ prohibit them from being possible leakages owing to the repeated fatigue of vibrations. In this paper, a non-contact 3-dimensional measurement system that can detect the vibrations of a solid body and monitor its vibrational modes is introduced. To detect the displacements of a body, a stereoscopic camera system is used, through which the major vibration types of solid bodies (such as X-axis-major, Y-axis-major, and Z-axis-major vibrations) can be monitored. In order to judge the vibration types, an artificial neural network is used. The measurement system consists of a host computer, stereoscopic camera system (two-camera system, high-speed high-resolution camera), and a measurement target. Through practical application on a flat plate, the measured data from the non-contact measurement system showed good agreement with those from the original vibration mode produced by an accelerator.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.199-206
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• 2015

In this study, a new diagnosis method which can predict the working states of a pipe or its element in realtime is proposed by using an artificial neural network. The displacement data of an inspection element of a piping system are obtained by the use of PIV (particle image velocimetry), and are used for teaching a neural network. The measurement system consists of a camera, a light source and a host computer in which the artificial neural network is installed. In order to validate the constructed monitoring system, performance test was attempted for two kinds of mobile phone of which vibration modes are known. Three values of acceleration (minimum, maximum, mean) were tested for teaching the neural network. It was verified that mean values were appropriate to be used for monitoring data. The constructed diagnosis system could monitor the operation condition of a gas pipe.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.781-786
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• 2017

The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN)/National Nuclear Energy Commission (CNEN) reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows.