• Journal of the Korean housing association
• /
• v.19 no.5
• /
• pp.111-120
• /
• 2008

The aim of this study is to present the design methods about manifold location being installed and size and to draw out the proper piping size as comparing the fluctuation of discharge with manifold size and residence size through the piping network analysis, when using the same faucet in accordance. The findings are summarized as follows, 1) an appropriate header main body pipe diameter was deemed to be $32{\sim}50\;mm$. 2) the research presented design measures for the application of appropriate water supply inlet pipe diameters according to residential buildings with various sizes. 3) the header direct branch piping method is ideal for small and medium-sized residential complexes, and the header branching and semi header methods are deemed to be more favorable for large residential complexes. 4) this study offered design measures for appropriate header system main body pipe diameters, water supply inlet pipe diameters, header system piping methods, application methods for functional auxiliary equipment units, and header system installation spaces and location.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.8
• /
• pp.826-831
• /
• 2009

The piping systems in nuclear power plant are composed of various typed pipes such as straight, elbow pipe, branch and reducer etc. The elbow is connected from straight pipe to another pipes in order to establish the complicated piping system. Elbow is one of very important components considering management of wall thinning degradation. It is however applied by various loads such as system pressure, earthquake, postulated break loading and many transient loads, which provoke simply the internal pressure, bending and torsional stress. In this study, firstly pipes in the secondary system of the nuclear power plant are classified as pipe size and type for selecting the investigating range. Next, a large number of finite element analysis considering the all typed dimensions of commercial pipe has been performed to find out the behavior of TES(twice elastic slop) plastic load of elbows, which is based on evaluation of the structural safety factor. Finally performance based structural safety factor was investigated comparing with maximum allowable load by construction code.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.1
• /
• pp.179-188
• /
• 1990

The characteristic of volumetric efficiency considering gas exchange process in a reciprocating engine is presented in this paper. The characteristic method is used for solving gas exchange problems of engine system in theoretical studies. The validity of the simulation is investigated by a comparison with the results obtained by the experiment which have been performed on the practical 4-cycle, 4-cylinder gasoline engine. The relationship between the volumetric efficiency and the intake pressure variation according to configuration of intake pipe, position of branch point, valve timing, compression ratio is clarified through simulation and experiment. The results predicted by the simulation are found to be in approximate agreement with those obtained by the experiment.

• Computers and Concrete
• /
• v.21 no.6
• /
• pp.717-726
• /
• 2018

Concrete pipelines are the most efficient and safe means for gas and oil transportation over a long distance. The use of nano materials and nono-engineering can be considered for enhancing concrete pipelines properties. the tests show that $SiO_2$ nanoparticles can improve the mechanical behavior of concrete. Moreover, severe hazard for pipelines is seismic ground motion. Over the years, scientists have attempted to understand pipe behavior against earthquake most frequently via numerical modeling and simulation. Therefore, in this paper, the dynamic response of underwater nanocomposite submerged pipeline conveying fluid is studied. The structure is subjected to the dynamic loads caused by earthquake and the governing equations of the system are derived using mathematical model via Classic shell theory and Hamilton's principle. Navier-Stokes equation is employed to calculate the force due to the fluid in the pipe. As well, the effect of external fluid is modeled with an external force. Mori-Tanaka approach is used to estimate the equivalent material properties of the nanocomposite. 1978 Tabas earthquake in Iran is considered for modelling seismic load. The dynamic displacement of the structure is extracted using differential quadrature method (DQM) and Newmark method. The effects of different parameters such as $SiO_2$ nanoparticles volume percent, boundary conditions, thickness to radius ratios, length to radius ratios, internal and external fluid pressure and earthquake intensity are discussed on the seismic response of the structure. From results obtained in this paper, it can be found that the dynamic response of the pipe is increased in the presence of internal and external fluid. Furthermore, the use of $SiO_2$ nanoparticles in concrete pipeline reduces the displacement of the structure during an earthquake.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.4
• /
• pp.23-32
• /
• 2013

This paper presents the simulation of the multi-cylinder 4-stroke cycle spark-ignition engine using a commercial simulation tool, AVL BOOST. Various models were examined to select the appropriate models that would best serve to analyze the main components of the intake and exhaust systems-the plenum chamber, the muffler and the exhaust manifold branch junction. For the plenum chamber and the muffler, the tank model and the pipe model were tested. In order to analyze the exhaust manifold branch junction, a complicated model which reflects the actual shape and involves pressure drops was compared to a simplified one. The results show that both the tank model and the pipe model are applicable with satisfying accuracies for the plenum chamber and the muffler. However, the tank model is more desirable in regards to convenience in modeling and efficiency in calculation. Though both the complicated model and the simplified model show satisfying accuracies for the exhaust manifold branch junction, the simplified model is recommended in regards to convenience in modeling and efficiency in calculation.

• Journal of the Korean Institute of Gas
• /
• v.8 no.3 s.24
• /
• pp.1-7
• /
• 2004

The polyethylene pipe can use semi-permanent because of the high corrosion resistance with chemical stability. In addition to, there is the merit that is an easy to establish and to maintain. However, as the reason that it is simply degraded when the polyethylene pipe was exposed to the outside, mainly it is used to lay under the ground with low-pressure gas transportation pipe. In this study, the nondestructive evaluation method was used to maintain the integrity of the polyethylene pipe. We simulated the various defects on the polyethylene pipes, and then the AE signal occurred according to the impact test of steel ball was evaluated by the acoustic emission method. From the results, the waveform and dominant frequency could be distinguishing from the defect shapes of polyethylene pipe. Especially, in the case of notch defect, the AE signals occur different by the angle and depth of the notch.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.2
• /
• pp.211-216
• /
• 2014

Using a high-rise building water piping after hydrostatic test of the reliability of the leak to be completed if the pressure is maintained until the leak is not commercially available considered. Due to the nature of high-rise buildings and the construction period will take several years from the lower levels of use of the water supply and fire fighting water pipe construction is in progress, the order of which I do most of the first pipe to the construction and more than three years. So kind of riser pipe is complete, install the valve in the basement by installing an automatic pump to maintain a constant pressure after hydrostatic test and after each floor plumbing piping is complete, the progress of the hydrostatic test without undergoing a separate branch pipe the valve is opened automatically when the number of the pressing pressure of the structure. I kind of do and keep working pressure of pipe until the completion of the construction work to keep the damage to human error when it is intended to prepare. In winter, the frost protection and an alternative to drainage water pipe is damaged or deformed, even if unaware of the finishing work to the building, the use of the damage caused by a leak in a after construction of finish work to be expected. Alternative to reduce this damage if the pressure test without fear of freezing to help maintain long-term commercial pressures may be considered.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.9
• /
• pp.1103-1108
• /
• 2012

A main steam pipe system is a branch pipe that connects a boiler with a turbine. Water hammering analysis is very important for limiting the damage caused to pipe systems by operation conditions. Water hammering created by an unsteady flow in pipeline systems can cause excessive change in pressure, vibration, and noise. The main steam pipe structure should be designed to safely maintain the pressure pulsation and several vibrations under operation environments. This study evaluated the structural integrity of a main steam pipe during suspended and normal operation by using the ASME fatigue life methodology and finite element analysis. In the analysis, water hammering was used for transient analysis. The calculated alternating stress and fatigue stress were compared with the applicable limits of ASME fatigue life. All the evaluation results satisfied the requirements of the ASME fatigue life.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.04a
• /
• pp.63-66
• /
• 2003

Thermoforming of fiber reinforced thermoplastic (FRTP) braided tubes was studied as a new forming technique. FRTP braided tubes with four plies are fabricated by the pressure bonding method are used in thermoforming. Bulge forming, bending process, pipe fittings and FE analysis are carried out in this study. In bulge forming the composite tube can be expanded up to about two times initial diameter. The suggested bending process can be obtained bent products with various bending radii. In pipe fitting it is possible to fabricate T-shape fitting, cross fitting and two-branch fitting. These results exhibit developed forming processes become useful processes for textile composite tubes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.652-657
• /
• 2000

In this paper, Firstly, it is shown that the high vibration source of piping system is the pulsation transmission of pipe line element, such as, orifice plate, valves and the control valve is a broad band source and the branch wall and the cavity have vortex frequency. Secondly, in order to decrese the high vibration of piping system, some practical Friction damper with high damping have been developed and its effectiveness is investigated as installing it at piping system practically.