• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.1-10
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• 2021

In this study, a circular pipe can be installed by suction pressure for construction on soft ground with a low-water level. A series of laboratory-scale model tests were conducted in sandy ground to comprehend the suction pressure of the circular pipe in low-water levels. For repeated tests on saturated sandy soil, a container was mounted with three vibration generators on the floor. A repetitive vibration was applied using the vibration system for ground compaction. In the model tests, different diameters and thicknesses on saturated sandy soil with a water depth were considered. The result showed that the suction pressure increased with increasing penetration depth of the circular pipe. Moreover, the suction pressure required to penetrate the pipe decreased with increasing diameter. In the low-water level, the total suction pressure measured at the top lid increased because additional suction pressure is required to lift the water column. On the other hand, this led to a decrease in suction pressure to penetrate the circular pipe because the weight of the water column is applied as a dead load. Therefore, it is necessary to consider the water level to design the required suction pressure accurately.

• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1648-1660
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• 2004

The suction nozzle of a vacuum cleaner was modified to enhance the power performance and to reduce the airflow-induced acoustic noise. The suction power efficiencies of the vacuum cleaner were measured for various nozzles; (1) original nozzle, (2) original nozzle with modified trench height, (3) original nozzle with modified connecting chamber, and (4) a combination of (2) and (3). In addition, the suction pressure and sound pressure level around the suction nozzle were measured to validate the reduction of acoustic noise. The power efficiency and mean suction pressure increased when the trench height of the suction nozzle was increased. This was attributed to the suppression of the flow separation in the suction channel. Modification of the connecting chamber in the original nozzle, which had an abrupt contraction from a rectangular chamber into a circular pipe, into a smooth converging contraction substantially improved the suction flow into the connecting pipe. When both modifications were applied simultaneously, the resulting suction nozzle was more effective from the viewpoints of aerodynamic power increase and sound pressure level reduction.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.10
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• pp.756-762
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• 2014

This paper dealt with numerical estimation of the pressure pulsation of the refrigerant in a suction pipe of the compressor. The behavior of the pressure pulsation was assumed to satisfy the wave equation. The boundary conditions and properties of refrigerant are necessary as input data of the simulation. The pulsating pressures at 15 points in a pipe were measured simultaneously from the pressure transducers. From the experimental data, the complex phase speed and impedance at the end of the pipe of the refrigerant were estimated using the signal processing and used as the input conditions of the numerical analysis. A commercial acoustic software was used to solve the behavior of pressure pulsation. The numerical results for the pressure pulsation in a pipe with and without expansion chamber were carried out and compared with those by experiments. Finally, numerical procedure to estimate the pressure pulsation in a pipe was established and verified.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.779-780
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• 2014

This paper dealt with numerical estimation of pressure pulsation of the refrigerant in a suction pipe of the compressor. To evaluate the effect of reduction of pressure pulsation, a pipe system with tube was simulated using F.S.I.(Fluid-structure interaction) analysis. A commercial program was used for calculating behavior of pressure. The numerical simulation for pressure ratio of before and after going though internal structure were carried out. As a result, it was verified that the pressure after passing structure is less than the pressure before passing internal structure depending on the longitudinal frequency of structure.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.8
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• pp.849-855
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• 2015

A better flow condition for the intake of pump is provided by the sump pump that connects the forebay to the intake of the pump station. If the suction sump is improperly shaped or sized, air-entraining vortices or submerged vortices may develop. These phenomena may greatly affect pump operation if vortices become sufficiently large. Moreover, any remaining vortices in the pump flow passage may result in an increase in the noise and vibration of the pump. Therefore, the vortices in the pump flow passage must be reduced to achieve good pump sump station performance. In this study, the effect of suction pipe leaning angle on the pump sump's internal flow is investigated. Additionally, a pipe type with an elbow shape is investigated. The results show that the air entraining vortices occur under the condition of a water level ratio H/D = 1.31 for each suction pipe type.

• The KSFM Journal of Fluid Machinery
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• v.19 no.6
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• pp.61-67
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• 2016

In this study, STAR-CD-based CFD techniques was used to analyze velocity distribution and pressure distribution according to the variation of angels at $45^{\circ}$, $60^{\circ}$ and $90^{\circ}$ a suction pipe when inlet velocity condition is 1 m/s. SIMPLE maritime law used for analytical algorithm and the results of CFD analysis evaluated by particle image velocimetry (PIV). The results of CFD analysis in this study have revealed that the optimal angle of a suction pipe for a jet pump is $90^{\circ}$ and the PIV test has showed the same results. Therefore, it is thought that when CFD is used to analyze the flow characteristics of a jet pump it would be possible to produce optimal designs of its devices.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.337-340
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• 2001

The suction muffler of a reciprocating compressor is used for reducing noise produced by pressure pulsations. According to the shape, the suction muffler is classified into one-chamber type, two-chamber type, Helmholtz resonator type, pipe-resonator type, and so on. These mufflers are used according to the characteristics of the frequency of compressor noise. In this study, four pole parameters have been used for calculating Transmission Loss of the muffler, and Insertion Loss has been acquired for the optimum design of the muffler by the experiment.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1037-1042
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• 1990

The air-fuel ratio of an internal combustion engine must be controlled with accuracy for the improvements of exhaust emission and fuel consumption. Therefore, it is necessary to measure the exact instantaneous amounts of fuel and suction air, so we carried out the experiments for measuring the air flow velocity in a suction pipe of an internal combustion engine using three types of instantaneous air flowmeter. The results obtained can be summarized as follows: (1) The laminar-flow type flowmeter is able to measure both the average and the instantaneous flow rate, but it is necessary to rectify the pulsating air flow in the suction pipe. (2) The a spark-discharge type flow velocity meter is able to measure the instantaneous air velocity, but it is necessary to choose the suitable electrode form and the spark character. (3) The tandem-type hot-wire flow velocity meter indicates the instantaneous flow velocity and its flow direction.

• Journal of Advanced Marine Engineering and Technology
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• v.14 no.4
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• pp.72-80
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• 1990

In this paper, the gas dynamic effects of the suction pipe systems which have resinators are investigated on the volumetric efficiency are theoretically investigated by the engine performance simulation program which has been already developed. As the results, the optimum design method of the suction pipe system which has the overall high the flat characteristic curve of volumetric efficiency is developed in case of one cylinder engine.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.201-204
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• 2008

Vortex and swirl occurring in a pump suction intake sump normally reduce the performance and disturb the safe operation of the circulation water pump in thermal power plants. This paper presents a case study of one particular intake sump design via a CFD analysis and a hydraulic model testing. The physical experiments and numerical analysis were performed under two flow and three level variation conditions. The vortex patterns around the pump suction pipe have been predicted by a commercial CFD code with the k-${\varepsilon}$ model. The model tests were conducted on a 1/10 model for a practical intake sump. The location, number and general pattern of the free surface vortex and submerged vortex predicted by CFD simulation were found to be a good agreement with those observed in the model testing.