• International Journal of Fluid Machinery and Systems
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• v.4 no.3
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• pp.317-323
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• 2011

Mini centrifugal pumps having a diameter smaller than 100mm are employed in many fields; automobile radiator pump, ventricular assist pump, cooling pump for electric devices and so on. Further, the needs for mini centrifugal pumps would become larger with the increase of the application of it for electrical machines. It is desirable that the mini centrifugal pump design be as simple as possible as precise manufacturing is required. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, we started research on the mini centrifugal pump for the purpose of development of high performance mini centrifugal pumps with simple structure. Three types of rotors with different outlet angles are prepared for an experiment. The performance tests are conducted with these rotors in order to investigate the effect of the outlet angle on performance and internal flow condition of mini centrifugal pumps. In addition to that, the blade thickness is changed because blockage effect in the mini centrifugal pump becomes relatively larger than that of conventional pumps. On the other hand, a three dimensional steady numerical flow analysis is conducted with the commercial code (ANSYS-Fluent) to investigate the internal flow condition. It is clarified from the experimental results that head of the mini centrifugal pump increases according to the increase of the blade outlet angle and the decrease of the blade thickness. In the present paper, the performance of the mini centrifugal pump is shown and the internal flow condition is clarified with the results of the experiment and the numerical flow analysis. Furthermore, the effects of the blade outlet angle and the blade thickness on the performance are investigated and the internal flow of each type of rotor is clarified by the numerical analysis results.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.8
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• pp.1203-1210
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• 2004

It was reported recently that the pump head degradation near the best efficiency point from single-phase flow to the break-down due to air entrainment became less in a screw-type centrifugal pump than in a general centrifugal pump. In this paper, I carried out internal pressure measurements and visualizations, and investigated the various physical phenomena occurring inside a screw-type centrifugal pump operated in air-water two-phase flow. The results could give some characteristics about the degradation of pump performance on air-water two-phase flow.

• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.1 s.244
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• pp.87-94
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• 2006

This paper presents the hydrodynamic design and performance analysis method for a miniaturized centrifugal blood pump using three-dimensional computational fluid dynamics (CFD) code. In order to obtain the hydraulically high efficient configuration of a miniaturized centrifugal blood pump for cardiopulmonary circulation, a well-established commercial CFD code was incorporated considering detailed flow dynamic phenomena in the blood pump system. A prototype of centrifugal blood pump developed by the present design and analysis method has been tested in the mock circulatory system. Predicted results by the CFD code agree very well with in vitro hydraulic performance data for a centrifugal blood pump over the entire operating conditions. Preliminary in vivo animal testing has also been conducted to demonstrate the hemodynamic feasibility for use of centrifugal blood pump as a mechanical circulatory support. A miniaturized centrifugal blood pump developed by the hydraulic design optimization and performance prediction method presented herein shows the possibility of a good candidate for intra and extracorporeal cardiopulmonary circulation pump in the near future.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.4
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• pp.383-390
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• 2016

In this paper, experiment and dynamics simulations were carried out to identify and reduce the out-of-plane vibration that occurs in a centrifugal fan of an air conditioner installed to a wall. In a wall-installed air conditioner, large space between a case and heat exchanger is often required for the fan to avoid the collision with the case and exchanger. This large space hinders the slim design of the air conditioner even if air conditioner market demands a slim air conditioner. In the present study, in order to determine the cause of the vibration in the centrifugal fan, the out-of-plane vibration and the physical properties were investigated, and the dynamic characteristics of the centrifugal fan were obtained by experiments. Based on these experiments, a dynamic simulation model was established to determine the cause of the out-of-plane vibration of the centrifugal fan. It was found that the main factor of out-of-plane vibration in the centrifugal fan is the axial misalignment between the centrifugal fan and the motor shaft.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.05a
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• pp.151-157
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• 1999

In this study, tile characteristics of three dimensional flow fields in centrifugal flump impeller are investigated by numerically. Detailed analysis and understanding of flow field in centrifugal pump are very important to predict performance of components. The three dimensional viscous fluid flow in centrifugal pump is distingushed isentropic process region from irreversible process region by wall shear effect, secondary flow, centrifugal and Coriolis forces, variation of boudary layers. Development of low momentum region by viscous fluid flow in the centrifugal impeller causes stall and blockage which is irreversible process region, and resulting in decrease of the performance and efficiency of centrifugal pump. Especially, the result is that Coriolis and centrifugal forces are most powerful factors which are increasing the irreversible region.

• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.874-881
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• 2011

The present study describes a new technique to extract the primary silicon from an Al-Si alloy melt using centrifugal force during its solidification. The primary silicon was separated from an Al-50 wt.%Si alloy by centrifugal force in the form of a foam, which facilitated subsequent acid leaching to extract the pure silicon due to its wide surface area. The foam recovery after centrifugal separation was decreased as centrifugal acceleration was increased. The final recovery after acid leaching became closer to the solid fraction of the alloy, which was calculated from the Al-Si binary phase diagram, with increasing centrifugal acceleration due to the effective removal of the attached Al on the foam. The purity of the primary silicon obtained by the centrifugal separation method was over 99.99%, with only aluminum being also present.

• The KSFM Journal of Fluid Machinery
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• v.16 no.2
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• pp.27-34
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• 2013

As the operating range of centrifugal pump is expanded recently, the various suction conditions are demanded. The most important problem in the suction conditions is cavitation. In this study, to analyze the characteristics for such the cavitation, first the validity of the numerical analysis was certified through comparison with the experimental result of performance curve according to flow rate for the industrial centrifugal pump. At this time, the transient numerical analysis for the full type model of the centrifugal pump was performed to get more accurate results. The numerical analysis on the cavitation of centrifugal pump were conducted on the two-phase flow as the same method of one-phased flow.

• The KSFM Journal of Fluid Machinery
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• v.3 no.4 s.9
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• pp.44-51
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• 2000

The present study has been conducted to design the high efficiency centrifugal compressor for a R134a turbo-chiller. The centrifugal compressor consists of an impeller with splitters, two vaneless diffusers, a low-solidity vaned diffuser and a volute. A cycle analysis program for a turbo-chiller was developed to obtain compressor design parameters and requirements. We have designed the high efficiency centrifugal compressor by applying the repeated design procedure including a meanline design, a 3D geometry generation and fluid dynamic loading calculations.

• The KSFM Journal of Fluid Machinery
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• v.14 no.2
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• pp.11-16
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• 2011

This paper presents a numerical study of casing treatments on a centrifugal compressor stage to improve stability and the surge margin. High efficiency, a high pressure ratio, and a wide operating range are required for a high performance centrifugal compressor. In the present study, a ring groove arrangement was applied to the transonic centrifugal compressor. According to the numerical analysis using a commercial code ANSYS-CFX, the unstable phenomena limiting the range of the centrifugal compressors were compared with and without a ring groove. Although the ring groove decreased the efficiency, but increased the operating range by suppressing a flow separation at the leading-edge of the impeller especially near shroud part. Newly designed ring groove arrangement improved the compressor performance and increased the operating range of the compressor.