• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.43-48
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• 2004

A screw-type centrifugal pump was manufactured to carry solids primarily and its impeller has a wide flow passage. However, the effect of flow passage shape on delay of the choke due to entrained air has not been clarified yet. Moreover, because its impeller has a particular shape, only few studies have tried to clarify the pump performance and details of internal flow pattern of that pump. For that reason, we carried out the pump performance experiment under air-water two-phase flow condition with different impeller tip clearances, pump rotational speeds and void fractions by using a small screw-type centrifugal pump designed to acquire basic data. In a general centrifugal pump, it was reported that loss of pump head from single-phase flow to the choke due to air entrainment new the best efficiency point was large. However, the loss near the best efficient point in a screw-type centrifugal pump became less than that in a general centrifugal pump.

• The KSFM Journal of Fluid Machinery
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• v.6 no.2 s.19
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• pp.29-33
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• 2003

The periphery pump (or regenerative pump) has been generally applied in the automotive fuel pump due to their low specific speed (high heads and small flow rate) with stable performance curves. In this study, the performance prediction of side channel type periphery pumps has been developed. The prediction of the circulatory flow rate is based on the consideration of the centrifugal force field in the side-channel and in the impeller vane grooves. For the determination of performance curve (head-flow rate), momentum exchange theory is used. The effects of various geometric parameters and loss coefficients used in the performance prediction method on the head and efficiency are discussed, and the results were compared with experimental data.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.581-584
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• 2002

The periphery pump(or regenerative pump) has been generally applied in the automotive fuel pump due to their low specific speed(high heads and small flow rate) with stable performance curves. In this study, the performance prediction of side channel type periphery pumps has been developed. The prediction of the circulatory flow rate is based on the consideration of the centrifugal force field in the side-channel and in the impeller vane grooves. For the determination of performance curve(head-flow rate), momentum exchange theory is used. The effects of various geometric parameters and loss coefficients used in the performance prediction method on the head and efficiency are discussed and the results were compared with experimental data.

• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.83-88
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• 2014

Pumps are widely used in industrial plants, energy systems, ships etc. Generally they consume nearly 20% each nation's total electrical energy. The objective of this study is to find performance evaluating method for variable-speed drive pump. In order to evaluate the variable-speed pump performance energy saving rate for the variable-speed pump is applied and compared with that of constant-speed pump.

• The KSFM Journal of Fluid Machinery
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• v.14 no.1
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• pp.11-17
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• 2011

The numerical study was conducted to investigate the pump performance due to impeller related parameters change in centrifugal pump of very low specific speed by using CFD code. A small centrifugal pump whose specific speed is $N_s=76.2$ was used, and the performance characteristics were discussed for different number of vanes, rotational speed, and the length and height of vane. The numerical results at a very low specific speed show that the increase of the number of vanes has little effect on improvement of output pressure but results in the reduction of pressure fluctuation, and that the head increases with the increase in the rotational speed. The decreasing the length of vane has a considerable reduction of the capacity coefficient in comparison with decreasing the height of vane.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.61-64
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• 2000

In order to analyse the effect of the fluid viscosity changes on the centrifugal pump, the computer simulation method and the performance correction chart are used. The centrifugal pump is designed using the traditional method, and the 3D computational grid is generated for the impeller and casing. Working fluids are water, high viscous oil and muddy water. The viscosity of muddy water is measured by the unsteady capillary tube viscometer. The pump performances are predicted well through the computer simulation. The performance curves of head and efficiency for oil and muddy water are decreased. The torques of oil and muddy water, which is calculated by performance correction chart are predicted at a lower value than the computer simulation.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.421-434
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• 2018

Water supply/intake pumps operation use 70~80% of power costs in water treatment plants. In the water treatment plant, seasonal and hourly differential electricity rates are applied, so proper pump scheduling can yield power cost savings. Accordingly, the purpose of this study was to develop an optimal water supply pump scheduling scheme. An optimal operation method of water supply pumps by using genetic algorithm was developed. Also, a method to minimize power cost for water supply pump operation based on pump performance derived from the thermodynamic pump efficiency measurement method was proposed. Water level constraints to provide sufficient disinfection performance in a clearwell and reservoirs were calibrated. In addition, continuous operation time constraints were calibrated to prevent frequent pump switching. As a result of optimization, savings ratios during 7 days in winter and summer were 4.5% and 5.1%, respectively. In this study, the method for optimal water pump operation was developed to secure disinfection performance in the clearwell and to save power cost. It is expected that it will be used as a more advanced optimal water pump operation method through further studies such as water demand forecasting and efficiency according to pump combination.

• The KSFM Journal of Fluid Machinery
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• v.1 no.1 s.1
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• pp.81-89
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• 1998

In this study, the effects of the impeller shapes on the pump performances of the non-clogging and the screw-type centrifugal pumps are experimentally studied. The characteristics of total head, efficiency and power of the non-clogging pump increase as the number of vanes increases. The screw-type centrifugal pump with the linear-shape vane shows a little better performance than that of the screw-type centrifugal pump with the curved-shape vane. The differences in the characteristics of total head, efficiency and power are, however, insignificant. Therefore, it is advisable that, considering the convenience of pump manufacturing, the screw-type centrifugal pump with the linear-shape vane should be used. This study also compares the pump characteristics of the non-clogging pump and screw-type centrifugal pump. The characteristics of total head and efficiency of the non-clogging pump are better than those of the screw-type centrifugal pump. The screw-type centrifugal pump requires more shaft power than the non-clogging pump.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.12
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• pp.821-827
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• 2010

Study on the performance characteristics of the solar hybrid system with heat pump operating temperature during winter season has performed by using an experimental test. The system performance and operating characteristics with the heat pump operating temperature, hour and load condition were investigated and analyzed. As a result, the hot water temperature was significantly affected by the heat pump operating temperature at the morning(time 1) and noon(time 2). However, hot water temperature was set by the radiation quality and collecting operation hour at the afternoon(time 3). In addition to the solar fraction was decreased for the high heat pump operating temperature because the heat pump operated with a long operating time and short operating period.

• Journal of Biosystems Engineering
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• v.24 no.4
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• pp.343-350
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• 1999

The ambient air is commonly used as low-temperature heat source for heat pump operation. However, the coefficient of performance(COP) of the air to water heat pump is decreased with the ambient air temperature drop. In this study to solve this problem, the AVACTHE(Automatic Variable Area Capillary Type Heat Exchanger) with 3 levels of heat exchange area(0, 1,495.4, 1,794.5$\textrm{cm}^2$)was installed in the refrigerant circuit of the heat pump. The AVACTHE effect on the performance of heat pump was tested with the ambient air temperature variation. The COP improvement of the heat pump could be achieved by the AVACTHE installation when below -5$^{\circ}C$ of the ambient air temperature.