• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1020-1025
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• 2007

The reciprocating type hydrogen compressor is for high pressure and volume. However this type compressor makes pulsation caused by mechanical characteristic. This type compressor also makes noise and vibration that cause negative effect to machine and working condition. Therefore, diagnosis and countermeasure are needed to decrease vibration for safety on hydrogen compressor. therefore in this paper, the numerical analysis and vibration measurement is conducted in order to investigate vibration characteristic and to evaluation vibration condition, Respectively

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1026-1030
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• 2007

A linear compressor used in a refrigerator has higher energy efficiency than a reciprocating compressor. But its vibration level is still severe than others. The vibration level of linear compressor at the frequency of 60Hz is dominant since it is the exciting frequency of a motor. Experimental approach to reduce the vibration needs much effort and long period. In this paper, simulation tool to predict the vibration of the shell of the linear compressor was developed. The piston, body and shell are assumed to be rigid, while the loop pipe is flexible. The results by the developed tool showed good agreements with those by experiments.

• Journal of KSNVE
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• v.9 no.4
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• pp.754-760
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• 1999

The valve motions of a reciprocating compressor generate the pressure fluctuation at the plenum which is a main source of noise and vibration of a compressor unit. But a cycle of a compressor process consists of complicated phenomena interacting in a short period of time. A mathematical model is developed by simplifying and idealizing the complicated phenomena to simulate the compressor process. The governing equations about the pressure and working fluid flow are developed from the unsteady Bernoulli equation. The pressure fluctuations at the plenums are derived from the Helmholz's resonator model. The valves are modeled as one degree of freedom spring-mass-damper system. This model is verified by the experimental results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.2
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• pp.173-179
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• 1998

An experimental study was conducted on the effect of compressor capacity control range of heat pump on the seasonal energy efficiency ratio with variation of the maximum and minimum compressor input frequencies. To obtain seasonal energy efficiency ratio, steady state test at the maximum, minimum and intermediate compressor speed and cyclic test at the minimum compressor speed should be conducted. Maximum input frequency was varied to 95Hz, 105Hz, and 115Hz, and the minimum input frequency was varied to 35Hz, 45Hz, and 55Hz. The seasonal energy efficiency ratio increased as the input frequency of the compressor decreased. The maximum input frequency had only slight effects on the SEER.

• The KSFM Journal of Fluid Machinery
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• v.8 no.1 s.28
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• pp.7-15
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• 2005

Tip clearance of centrifugal compressor affects the performance. Larger tip clearance results in lower efficiency. What really affects the performance is the running tip clearance, not the cold tip clearance. When the compressor is operating, blade strain and the pressure difference between impeller backplate and hub affects the running tip clearance. This paper describes measured running tip clearance and its effects on the performance of centrifugal compressor. Cold tip clearance before operation was 0.4 mm and running tip clearance varied from 0.86 mm to 0.25 mm with impeller exit pressure. As the pressure at impeller exit increases, the running tip clearance tends to decreases. The target running tip clearance for Compressor at $100\%$ speed was 0.3 mm, and it turned out to be exactly 0.30 mm from experiment.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.469-474
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• 2001

The feasibility of a oil-free motor-driven two-stage centrifugal compressor supported by air bump bearings is investigated. This centrifugal compressor is driven by 75kW motor at an operating speed of 39,000RPM md a pressure ratio of the compressor is up to 4. The analysis is performed, based upon bearing equilibrium position, bearing stiffness, Campbell diagram, unbalance response and stability. It is demonstrated in this paper that air bump bearings can be adopted well to a oil-free motor-driven centrifugal compressor.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.129-134
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• 2001

The paper presents the optimal design of a oil-free two-stage compressor, which is driven by 75 kW motor at an operating speed of 39,000 rpm, and the pressure ratio of which is up to 4. First, an attempt is made to obtain the optimal design of a bump bearing which supports a compressor rotor. Second, bump bearings and shaft are considered simultaneously, and the weighted sum of rotor weight and frictional torque is minimized. Finally, the optimal geometry of compressor wheel is considered. The mean efficiency and the - minimum efficiency are maximized respectively. The results presented in this paper provide important design information necessary to reduce the energy loss.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.86-92
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• 2010

A metal diaphragm compressor has been widely used for supplying a high pressures gas. This compressor mainly consists of gas oil space and metal diaphragm. Gas sucked in the gas space is compressed by an oscillating metal diaphragm existed between the gas and oil space. A non-return discharge and suction check-valve are components of the compressor that draw off the compressed oil and gas. Those components are self-actuated by differential pressures. Therefore, the rapid response and stable operating conditions are required. In the present study, to find out the dynamic behavior of the suction, discharge valve and diaphragm compressor, the unsteady flow field has been investigated numerically by using the unsteady two-way FSI (Fluid Structure Interaction) simulation method, $k-{\omega}$ turbulent model and mesh deformation.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2413-2422
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• 1994

The effects of compressor design conditions on the off-design performance of a single-shaft gas turbine engine have been studied. Three different geometric design conditions are considered and three different values for the specific mass flow rate at the inlet to the compressor are assumed. For each of nine compressor design, the off-design performance of the gas turbine engine is predicted using the method previously proposed by present authors. Results show that the predicted off-design performances are quite different from each other even though they have the same performance at design point: it means that compressor design conditions should be determined in consideration of the off-design performance of the engine. The specific mass flow rate at the inlet to the compressor is also shown that it might be optimized with respect to the net power of the engine.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.7
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• pp.1092-1100
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• 2004

This paper describes the application of fault tree technique to analyze of compressor failure. Fault tree analysis technique involves the decomposition of a system into the specific form of fault tree where certain basic events lead to a specified top event which signifies the total failure of the system. In this research. fault trees for failure analysis of screw type air compressor are made. This fault trees are used to obtain minimal cut sets from system failure and system failure rate for the top event occurrence can be calculated. It is Possible to estimate air compressor reliability by using constructed fault trees through compressor failure example. It is Proved that FTA is efficient to investigate the compressor failure modes and diagnose system.