• International Journal of Fluid Machinery and Systems
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• 제9권2호
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• pp.107-118
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• 2016

This paper focuses on the single stage and multistage performance characteristics of centrifugal mixed flow submersible borewell pump. This study reveals that the performance of single stage pump is higher than that of multistage pumps. The head, input power and efficiency of single stage pump are higher than the per stage head, per stage input power and efficiency of multistage pumps. This study is divided into three parts. In the first part, five prototype pumps were made in single stage and multistage construction and the performance tests were conducted. In the second part, numerical validation has been done for different turbulence models and grid sizes. k-Omega SST model has been selected for the performance simulation and was validated with the performance of the test pump with static pressure tappings. In the third part, single and three stage pump performance were simulated numerically and compared with experimental results. The detailed analysis of pressure and velocity distributions reveals the difference in performance of single and three stage pump, due to non-uniform flow and difference in averaged flow velocities at the subsequent impeller inlets except the 1st stage impeller inlet.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.1063-1069
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• 2022

In modern industry, vacuum has grown into an indispensable industrial field. The performance of the vacuum pump in the degasser system among mud treatment system facilities was verified by a numerical analysis method. The degasser system is an equipment for removing the gas contained in the mud, and it is a work process that requires a vacuum. This study analyzed the vacuum pump performance of the degasser used in drilling for resource development of onshore and offshore plants. The vacuum pump used in the degasser system was designed with a discharge rate of 0.099kg/s. The DM(Design Modeler) program of ansys workbench 17.2 was used to modify the model of the vacuum pump used in the degasser system. And for performance analysis, CFX, which is known to be suitable for rotating system analysis, was used. Finally the performance analysis results of the vacuum pump and the prototype performance test results were compared and analyzed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.593-596
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• 2002

Flows in a regenerative pump were calculated for several flow-rates, using the CFX-Tascflow. The calculated results show the vortex structure in the impeller and side channel. The predicted performance shows considerable discrepancy form the measured values for low flow rates. Main source of the difference is the leakage flow of pump strongly affecting the performance of pump. A simple correlation was proposed using calculated leakage flows through the parametric calculations of the simplified passage.

• 대한설비공학회지:설비저널
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• 제12권4호
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• pp.219-226
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• 1983

Cyclic heating performance of 3 ton air-to-air unitary heat pump installed in a residence in the Washington, D.C. area was determined by applying the bin method to field test result. Cyclic degradation coefficient Cn of heat pump may be expressed in terms of heating load factor HLF as the following : $$C_D=\frac{1-HLF^m}{1-HLF}$$ where $$C_D{\ge}m$$ The less is the value of exponent m, the better is, the performance of a heat pump, depending upon the heat pump design.

• 한국유체기계학회 논문집
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• 제14권1호
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• pp.24-33
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• 2011

A circulating pump with installation space constraints was developed satisfying performance requirements such as flowrate, head and NPSHAv. The development procedures are composed of conceptual design, configuration design, performance analysis by CFD and performance test which were established in KIMM. The developed pump is OH4 type centrifugal pump which has a mixed-flow type impeller, a double volute and a rigid coupling. As a result of tests, the pump proved to meet all the requirements including space constraints and performance.

• 한국유체기계학회 논문집
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• 제15권1호
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• pp.41-45
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• 2012

The effects of inducer tip clearance on the suction performance of a pump for turbopumps are investigated. Experiments for the pump with inducer tip clearances of 1.8% and 1.4% of blade height were performed. The experimental results showed that the suction performance of the pump increased as the tip clearance decreased. It seems that the suction performance of the pump becomes better with smaller tip clearances because the strength of the inducer backflow becomes weak with the decreased tip clearance.

• International Journal of Air-Conditioning and Refrigeration
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• 제12권2호
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• pp.61-69
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• 2004

In this study, on-site performance test of an air source heat pump which has a rated capacity of 10 RT is carried out. Since indoor and outdoor air conditions can not be controlled to satisfy the standard test conditions, experiments are done with the inlet air conditions as they exist. To estimate the performance of the heat pump for other conditions, the heat pump is modeled with a small number of characteristic parameters. The values of the parameters are determined from the few measurements measured on-site during steady operation. A simulation program is developed to calculate cooling capacity and power consumption at any other arbitrary operating conditions. The simulation results are in good agreement with the experiment. This study provides a method of an on-site performance diagnosis of an air source heat pump.

• 한국지열·수열에너지학회논문집
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• 제9권3호
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• pp.1-10
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• 2013

Open loop geothermal heat pumps have great potential where the groundwater resources are sufficient. Performance of open loop geothermal heat pump systems is considered higher than that of ground source heat pumps. Head and power calculation of submersible pumps, heat pump units, and piping are numerically based on regression data. Results shows that the system performance drops as the water level drops, and the lowest flow rates generally achieve the highest system COPs. The highest achievable cooling system COPs become 6.34, 6.12, and 5.95 as the groundwater levels are 5m, 15m, and 25m. The highest heating system COPs also become 4.59, 4.37, and 4.20. Groundwater level and submersible pump selection greatly influence the system performance of open loop geothermal heat pumps. It needs to be analysed during the design process of open loop geothermal heat pump system, possibly with analysis tools that include wide range of pump product data.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.534-542
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• 2012

Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed-loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As a result, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.

• 한국태양에너지학회 논문집
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• 제32권3호
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• pp.114-122
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• 2012

Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed -loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As results, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.