• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.680-683
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• 2002

In this paper, it has been investigated that the design and simulation of vacuum pump driven by linear motor. Vacuum pump consists of unified plunger and piston part, coils, inlet valve and outlet valve. Operating principal of vacuum pump show that air is to flow to go inside through the inlet valve when the magnetic force (16N) is exerted, whereas, air is to flow to go outside through outlet valve when spring farce (14.8N) is exerted. The results of simulation. it was turned out that reached vacuum pressure was about -0.55 bar at 150 seconds, magnetic force was loaded with 16 Newton, displacement of actuator was about 8mm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.585-588
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• 1995

In this study, the analysis of the static and dynamic characteristics of the load-sensitive hydraulic pump control system used in the hydraulic excavator was performed by hydraulic circuit ananlysis program. Thess results was verified by the experimental data of the hydraulic excavtor system. The responses on effective parameters of system at the controllable region and the pressure variation of the pump used in hydraulic excavator system was studied to enhance the static performace of the system. the parameter enhance dynamic sharacteristics was considerd.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.533-539
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• 1997

Pressure ripple of hydraulic vane pump results form flow ripple due to pump geometry and reverse flow through the discharge port due to compressibility of fluid and result in vibration and noise of connected hydraulic elements. In a ba;anced type vane pump, cam ring curve is important factor to influence the flow ripple. Therefore, to reduce the now ripple, it has been required that optimal selection of seal region by proper design of cam ring and each port position, and notches for preventing the excessive reverse flow. This paper has been performed analytical study of compression characteristics with major design parameter in side plate and cam ring, and examined into the role of notch and radius reduction ratio.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.569-572
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• 2002

In the present study, flow simulations of a solution pump fer an absorption chiller are performed. The results are compared to the experimental data. Since the cavitation is more likely to occur in a solution pump due to Its operation under vacuum condition, and the cavitation was not considered in the present computations, the computed and experimental results show large discrepancies. For more accurate performance prediction of a solution pump, a cavitation model is required in the flow simulation. Flows through an inducer are also studied to see the effect of design parameters on performance characteristics. It is shown from the results that, if not properly designed, recirculation legion may exist near the hub region of the Inducer, and the suction surface may experience higher pressure than the pressure surface of the inducer, which may deteriorate the performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.368-373
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• 2001

A major concern on high-energy centrifugal pump is the potential for interaction of two-phase flow phenomena with mechanical response of the pumping elements. The other concern is the pressure pulsations created from trailing edge of the impeller blade and flow separation and recirculation at partial load in centrifugal pumps. These interactions generating between rotor and casing cause dynamic pulsation on pump and exciting pipeline vibration. The higher severity responses, the more lead to failure of pump and system components. Finally, it cause severe axial vibration of single stage pump due to the hydraulic instability in flow condition below BEP.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.87-93
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• 1998

Pressure ripples of hydraulic vane pump results from flow ripples due to pump geometry and reverse flow through the discharge port due to compressibility of fluid and result in vibration and noise of connected hydraulic elements. In a balanced type vane pump, cam ring curve is important factor to influence the flow ripples. Therefore, to reduce the flow ripple, it has been required that optimal selection of seal region by proper design of cam ring and each port position, and notches for preventing the excessive reverse flow. This paper has been performed analytical study of compression characteristics with major design parameter in side plate and cam ring. and examined into the role of notch and radius reduction ratio.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.44-50
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• 2017

The shaft seal of the reactor coolant pump is installed on the upper side of the rotating shaft of the pump to seal the reactor coolant from flowing out between the rotating shaft and the non-rotating parts. In this study, the loading conditions for the normal operation and faulted conditions are identified and structural integrity evaluation is performed using the finite element stress analysis for the sealing apparatus of the APR 1400 reactor coolant pump. It is confirmed that the stress analysis results satisfy the design criteria at all loading conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.2
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• pp.201-206
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• 2017

In the study, the inner flow characteristics were analyzed by modifying the inner design parameter of the vane-type vacuum pump. The effect of pressure generated by the inner flow of pump on the rotor and vane was analyzed. The design parameter was analyzed using the angle variation of tilting and rotation of the vane. MRF was used for the analysis conducted using a virtual condition where the rotor and vane are rotated. The pressure gained from the load of the rotor and vane in the flow analysis is used for the structure analysis. Based on the results, the effect of variable vane design was revealed in structural strength. The effect of centrifugal and friction force generated during pump operation on structural strength was also analyzed.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.05a
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• pp.202-205
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• 2006

Recently, high vacuum pumps are widely used in the semi-conduction and liquid-crystal display ( LCD ) process. The composite-type high vacuum pumps are widely used in the various processes. In this study, the pumping performance of composite-type molecular pumps has been investigated experimentally. The experimented pumps are a compound molecular pump ( CMP ) and hybrid molecular pump ( HMP ). The CMP consists with helical-type drag pump, at lower part, and with turbomolecular pump ( TMP ), at upper part. The HMP consists with disk-type drag pump, at lower part, and with TMP, at upper part. The experiments are performed in the outlet pressure of $0.2\;{\sim}\;533\;Pa$. We have measured the ultimate pressure, compression ratio, and pumping speed

• Journal of Korean Vacuum Science & Technology
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• v.7 no.2
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• pp.27-32
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• 2003

A large cryo-pumping system composed of 4 cryosorption pumps was designed and manufactured to satisfy the pressure requirements of the NBI test stand. The cryosorption pump consists of a thermal shield/baffle assembly and a cryopanel coated with activated carbon granules. The thermal shield is cooled by liquid nitrogen, and the cryopanel by a commercial helium refrigerator. The operation characteristics and vacuum performance of the cryosorption pump were investigated. The cooling down time of the cryopanel to 20 K was about 6 hours with a liquid nitrogen consumption rate of about 35 L/hr. The maximum pumping speed of the cryosorption pump for the hydrogen gas measured by the steady pressure method was about 90,000 L/s.