• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.93-98
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• 2010

One of the most effective key factors to improve performance of automotive reciprocating compressor is the design of suction and discharge reed valves. Reed valves are also the major sources of compressor noise. Valve motion is highly coupled with refrigerant flow. In this study, a process of fluid-structure interaction analysis was developed to predict the cylinder inner flow and the dynamic behavior of valve simultaneously. Interface programs computational structural dynamics code. The full cycle simulations of compressor were performed using FSI analysis was alidated by comparing the simulation results with the experimental results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.5
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• pp.407-413
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• 2014

The diesel engine and reduction gear combination is one of the common propulsion system in a naval vessel. Since the diesel engine has torsional vibration caused by reciprocating motion of the mass and gas pressure force of the cylinder, high cycle torsional fatigue can be occurred. Therefore, ROK navy restricts the maximum stress of the propulsion shaft according to MIL G 17859D. In this paper, the root cause for the failure of the diesel engine and reduction gear connecting shaft occurred in typical naval vessel is investigated based on the measured bending and torsional moment according to MIL G 17859D procedure.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.105-111
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• 2003

The valve train system of engines has long been a sensitive area with respect to wear performance because of the high contact loads and surface sliding speeds encountered. In particular, wear problems of load-carrying components in relative motion, such as cam and tappet in valve train system have made troubles. To overcome these problems, combination of proper materials is important, as well as selecting of high wear performance materials. This paper presents the experimental result of friction and wear properties of ca/tappet materials. To investigate friction and wear properties for several combinations of materials, using commonplace tribometer(Plint 77, reciprocating type), we make a selection of a optimum material combination.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.710-711
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• 2014

In many cases, periodic noise occurs because most applications include motors, compressors and so on which have reciprocating motion. The noise usually contains tones at the fundamental frequency and at several higher harmonic frequencies in practice. For this type of noise, we developed a frequency-domain active noise control algorithm and determined that it's effective. However, the performance deteriorated for quasi-periodic noise. In this paper, we develop compensated frequency-domain active noise control algorithm for quasi-periodicity. And then, we implement computer simulation and compare the performance.

• Journal of Biomedical Engineering Research
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• v.35 no.2
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• pp.19-25
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• 2014

According to recent data more than 80% of people suffer from back pain, due to an aging and a poor posture, at least once in their life time, and 7~10% of them have chronic spine illness. Researchers over the years have studied on various spinal traction devices that utilize the force of traction, and have also reported clinical test results. However, most existing devices are too complicated and too expensive. In order to solve these problems, we have developed a new device in which the frame moves up and down and at the same time tilting angle of the frame is adjusted. We have analyzed the forces applied on the body as a function of tilting angle. And the result shows that the new device has achieved the force of traction, which is known to be effective for spinal rehabilitation.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.662-670
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• 1999

A numerical prediction was performed to clarify the air motion in the cylinder of an axisymmet-ric four-stroke reciprocating engine at its intake and compression stage. A scheme of finite volume method is used for the calculation. Modified $k-{\varepsilon}$ turbulence model is adopted and wall function is applied to the grids near the wall. The predicted mean velocity and rms velocity profiles showed a reasonable agreement with an available experimental data at its intake and compression stage. The predicted in-cylinder flow fields show that a strong turbulent twin vortex structure is pro-duced during induction but it commences to decay rapidly around inlet valve closure. The mean velocity continues to fall to a low level during compression but the turbulence intensity attains an approximate constant level.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.220-224
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• 2004

The present paper deals with the numerical study to analyze the self-starting performance of impulse turbine in a reciprocating air flow generated by sinusoidal motion of wave inside oscillating water column. Result was compared to that of Wells turbine, well-known wave energy conversion device, and showed that the impulse turbine has a superior self-starting ability. More detailed parametric study was performed to demonstrate the effects of moment of inertia of rotor, loading torque, tip clearance and angle of guide vane.

• Transactions of The Korea Fluid Power Systems Society
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• v.2 no.1
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• pp.1-8
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• 2005

Recently, swash plate type hydraulic axial piston motors/pumps are being extensively used in the world, because of simple design, light weight and effective cost. Structural problem of the swash plate type motor/pump is that tilting angle of swash plate should be limited to relatively small value and lateral farce on pistons has an undesirable effect in reciprocating motion. To solve these problems, piston rod mechanism, which is commonly used in bent axis type motor/pump, is considered to be applied to the swash plate type motor/pump. In this paper, kinematic analysis was done on the piston rod mechanism. A series of formula were derived and numerical calculations were done for a set of motor parameters.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.15-18
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• 1996

In the case of need for reciprocating motion, the study for application of Linear Oscillating Actuator(LOA) is being accomplished. LOA is the simpler and more efficient than other linear apparatus using the rotary motor because LOA produce the thrust force without any converter such as cam, clutch, rack, pinion and belt, etc. We designed the flat moving core type LOA and manufactured for trial. This paper shows the structure and dynamic characteristics of LOA.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.2
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• pp.89-102
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• 1993

In this experimental investigation, various plasma-sprayed zirconia contained coatings and a kind of alumina-zirconia coating were studied to gain a better understanding of their tribological behaviour under dry contact condition in a reciprocating motion at temperature of 200℃. Particular attention was made for finding appropriate coatings in cylinder liner/piston ring application with an emphasis on the antiwear property. In order to identify the wear mechanism, SEM(Scanning Electron Microscope), optical micrograph, and roughness tester were used. Alumina-zirconia and 8% yttria-zirconia were found to be most appropriate for the application to the cylinder liner/piston ring and, especially, alumina-zirconia exhibited highest wear-resistance and also showed good friction characteristics. Wear mechanisms of ceramic coatings identified.