• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.4
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• pp.280-286
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• 2008

In this study, characteristics simulation of heat pump system is investigated for heating and cooling using sewage water as a heat source. A simulation program for preestimate operation characteristics of heat pump system is developed. The performance of this system is resolved by several variables and the characteristics which is based on actual air and sewage temperature data. The simulation results agree well with the experimental values of COP. In the analysis of system characteristics, the COP is changed between $3\sim5$ in winter season for heating load, $4\sim6$ in summer season for cooling load. As the results of Life Cycle Cost analysis over a 15 year life cycle, the energy cost could be reduced by 250 million won if a heat pump system was used instead of a conventional boiler and an absorbtion refrigerator on the office building.

• Journal of the Korean Vacuum Society
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• v.10 no.3
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• pp.312-320
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• 2001

A Non-Evaporable Getter(NEG) pump was fabricated using Zr-V-Fe alloy modules to obtain $10^{-9}$ Pa range pressures. Pumping performances and activation characteristics were investigated and the pumping speeds for hydrogen, deuterium and carbon monoxide gases of the NEG pump were measured. And hydrogen desorption characteristics were examined during activation at $450^{\circ}C$. Futhermore the vacuum performance was compared with those of other high vacuum pumps as turbo-molecular pump, sputter-ion pump, and cryo pump by analyzing the residual gases of the system.

• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.14-23
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• 2006

The scroll pump is widely used in ultra clean vacuum systems. However, there is no commonly available information on the hydrogen pumping characteristics of this pump, which creates a difficulty in determining whether the scroll pump can be used or not in a fusion experiment system where hydrogen ,is the main working gas. In this paper the experimental setup, measurement procedures, experimental results, and discussions on the pumping speed, the maximum compression ratio and the back-streaming properties of the scroll pump, especially for the hydrogen gas, are reported.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.494-500
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• 2007

The comfort and quietness of vehicle has been improved greatly due to the development of technology in automobile industry. It is driven by reduction on the level of vibration and noise in powertrain system. However, the hidden problems in automobile parts become noticeable since the vehicle has been better in overall performance. One of them is related to the fuel pump system. Therefore, this study is focused on investigating the characteristics of fuel pump and fuel tank first, and then comparing the data before and after installation of fuel pump system in a testing vehicle. Additionally, the measured data will be analyzed to identify the problems and find a solution to improve the level of noise and vibration in fuel pump system.

• Applied Science and Convergence Technology
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• v.24 no.1
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• pp.9-15
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• 2015

The practical pumping speed of a dry pump is considerably lower than the intrinsic speed because of back-streaming through finite gaps of the rotor assembly. The maximum compression ratio and the ultimate pressure of the pump are also directly influenced by the back-streaming rate. Therefore, information on the gap conductance, which determines the back-streaming characteristics of the rotor assembly, is the most important key for estimating the pumping performance of a dry pump. In this paper, the feasibility of calculating analytically the pumping performance of a multi-stage Roots pump, one of the most popular types of dry pumps, by quantifying the gap conductance in a rational way, is discussed.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.3
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• pp.463-469
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• 2012

The efficiency of the flow mixed pump installed within the bell-mouth in the sump is reduced by the flow characteristics of around intakes. Strong submerged vorticies can be successfully suppressed by installing an AVD(anti-submerged vortex device) on the bottom of pump intake channel just below the bell-mouth. Sump model with AVD device basin is designed and the characteristics of submerged vortex is investigated in the flow field by numerical simulation. In this study, a commercial CFD code is used to predict the efficiency of the pump with the AVD installation in the pump station accurately.

• Tribology and Lubricants
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• v.14 no.1
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• pp.79-84
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• 1998

This paper presents the experimental study of the dynamic internal pressure within a vane pump. The measurement of the dynamic internal pressure acting on the line contact between the vane and the camring in a vane pump with intravanes have been investigated. The variations of the radial acting force of a vane are calculated from previously measured results of dynamic internal pressure in four chambers surrounding a vane, and the variations of the film thickness are estimated in both the rotational speed ranges from 600 to 1200 rpm and the delivery pressure ranges from 1 to 14 MPa. The experimental technic has been established to obtain the data for performance analysis, such as reaction forces between vane and camring, friction wear at the contact regions, leakage characteristics and net forces upon the pump shaft in case of the unsteady load which is forced to the intravane pressure balance type vane pump.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.589-592
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• 2002

A commercial CFD code is applied to analyze the 3-D viscous flow field within vertical multi-stage centrifugal pump including impeller of centrifugal pump with 6 blades and guide vain with 11 blades. The numerical analysis of vertical multi-stage centrifugal pump is performed by changing flow rate from $8\;to\;26\;m^{3}/h$ at the constant 3500rpm. The characteristics such as total pressure coefficient, total head, water horse power, power efficiency are represented according to flow rate changing. In the future, we will need to perform flow calculation of vertical multi-stage centrifugal pump by considering meridional shape of impeller.

• Journal of Power System Engineering
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• v.1 no.1
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• pp.35-41
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• 1997

Annular jet pump can be used for the transportation of solid materials and fish. The effect of mixing chamber on the characteristics of annular jet pump is sought in this paper. Experiments were done for several reducing angles of mixing chamber, and for several throat area. Water was used for both the primary fluid and secondary fluid. A vortex was observed for the straight mixing chamber, but it was not observed for the mixing chamber whose reducing angle is $18^{\circ}$ or higher. The efficiency curves for the annular jet pump are presented in this paper, showing the annular jet pump which has 240 reducing angle and $0.611{\sim}0.73$ value of At/As. is most effective among the tested several annular jet pumps.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.5
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• pp.594-600
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• 2012

In this study, the mathematical model of the underwater discharge system using a centrifugal pump was derived and the rotating speed profiles of the pump which satisfied the discharge performance requirements were obtained through the underwater discharge simulations. The simulation results showed that the dynamic characteristics of a projectile were greatly affected by the rotational speed of the pump, however, hardly by the discharge depth. It is anticipated that the simulation model can be used to derive the design parameters and analyze the performance concerning the underwater discharge system using a centrifugal pump.