• Journal of the Korean Society of Visualization
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• v.8 no.4
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• pp.19-25
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• 2010

The flow field measurements were conducted on the planes between impeller blades, and the gap between the impeller and turbine blades under speed ratio of 0.4. The study showed that high velocity regions move from locations near the suction surface of the impeller to the pressure blade, shroud corner as flow progresses from the mid-chord of impeller passage to exit and out into the gap region. Planes 3 through 5 also showed flow reversal occurring in the area near the shell surface and progress far into the impeller passage from the impeller passage exit, near shell surface. This affected the converter efficiency negatively. This study would aid in the construction of higher accuracy CFD models of this complex turbomachinery device.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2261-2270
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• 1995

Flow patterns were measured in an unshrouded centrifugal impeller. The flow rate in measurements was fixed at the value corresponding to a nearly zero incidence at the blade inlet. By using a single slanted hot-wire probe and a Kiel probe mounted on the impeller hub disk, the 3-D relative velocities and the rotary stagnation pressures were measured in seven circumferential planes from the inlet to the outlet of the impeller rotating at 700rpm, which diameter is 0.39 meter, and the static pressures and the slip factor at the impeller outlet were calculated from the measured values. From the measured data, the primary/secondary flows, the leakage flows, the wake-jet flows, static pressure distribution on blade surfaces and the wake production mechanism in the impeller passage were investigated.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.6
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• pp.71-77
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• 2001

We have developed the exclusive CAD/CAM system for the machining of impeller blades. This study is about the mod-eling method for the effective machining of impeller blades farmed by ruled surface. As the impeller is consisted of boss part and blade part, the boss is modeled by rotational surface of hub curve on z-axis and the blade is described by ruled- surfaces between hub curve and shroud curve. This modeling process can be carried out on the software developed in this study. And, the developed software can describe the impeller as a solid model through interface with Solid-Works soul- ware. The developed software containing the interface method proposed in this study was very effective fur impeller modeling.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.359-364
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• 2005

Centrifugal pump shows the strongest secondary flow. Wake is formed near pressure surface close to hub at impeller exit for centrifugal pump impeller. Pressure gradient drives secondary flow in the inducer region, while in the remaining region the following sources drive together: > Pressure gradient > Coriolis force Low-momentum fluid near suction surface hub moves toward pressure surface hub in mixed-flow pump impeller. Tip leakage vortex dominate secondary flow in axial-flow pump impeller. Tip leakage vortex dominate secondary flow in axial-flow in axial-flow pump impeller

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.33-40
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• 2002

The hydraulic performance analysis of a pump system composed of an inducer and impeller for the application on turbopumps has been performed using three-dimensional Wavier-Stokes equations. A simple mixing-plane method and a full interaction method are used to simulate inducer/impeller interactions. The computations adopting two methods show almost similar results due to the weak interaction between the inducer and impeller since the inducer outlet blade angle is rather small. But, because the inducer and the impeller are closely spaced near the shroud region at the interface, flow angles at the impeller inlet show different results between two methods. Thus, the full interaction method predicted about $2\%$ higher pump performance than the mixing-plane method. And the effects of prewhirl at the impeller inlet are also investigated. As the inlet flow angle is increased, the head rise and the efficiency are decreased. The computational results are compared with experimental ones. The computational results at the design point show good agreements with experimental data. But the computation was found to under-predict the head rise at high mass flow rates compared to the experiment, further study must be followed in terms of the computation and experiment.

• International Journal of Fluid Machinery and Systems
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• v.4 no.3
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• pp.349-359
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• 2011

An unsteady numerical analysis has been carried out to study the strong impeller volute interaction of a centrifugal pump with six backward swept blades shrouded impeller. The numerical analysis is done by solving the three-dimensional Reynolds Averaged Navier-Stokes codes with standard k-${\varepsilon}$ two-equations turbulence model and wall regions are modeled with a scalable log-law wall function. The flow within the impeller passage is very smooth and following the curvature of the blade in stream-wise direction. However, the analysis shows that there is a recirculation zone near the leading edge even at design point. When the flow is discharged into volute casing circumferentially from the impeller outlet, the high velocity flow is severely distorted and formed a spiraling vortex flow within the volute casing. A spatial and temporal wake flow core development is captured dynamically and shows how the wake core diffuses. Near volute tongue region, the impeller/volute tongue strong interaction is observed based on the periodically fluctuating pressure at outlet. The results of existing analysis also proved that the pressure fluctuation periodically is due to the position of impeller blade relative to tongue.

• International Journal of Fluid Machinery and Systems
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• v.3 no.3
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• pp.245-252
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• 2010

It's known that pump head of centrifugal impeller with lager blade outlet angle is kept higher in air-water two phase flow condition, though the efficiency in water single phase flow condition is inferior. In the present study, a centrifugal impeller with variable blade outlet angles, that has higher efficiencies in both water single phase flow and air-water two phase flow conditions, is proposed. And the performances of the centrifugal impeller with variable blade outlet angles were experimentally investigated in both flow conditions of single and two-phase. In addition, effects of installing diffuser vanes on the performances of centrifugal pump with movable bladed impeller were also examined. The results are as follows: (1) The movable bladed impeller that proposed in this study is effective for higher efficiency in both water single phase and air-water two phase flow conditions. (2) When diffuser vanes are installed, the efficiency of movable bladed impeller decreases particularly at large water flow rate in water single-phase flow condition; (3) The performances of movable bladed impeller are improved by installing of diffuser vanes in air-water two-phase flow condition at relatively small water rate. The improvement by installing of diffuser vanes however disappears at large water flow rate.

• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.21-28
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• 2014

Propellent should be pressurized inside the turbopump to gain high thrust in a projectile. Turbopump is composed of an inducer, which prevents impeller performance deterioration, and an impeller. Several types of cavitation occur inside the inducer, numerous experiments and CFD simulations are conducted. Though, an inducer takes only small portion of total head of the pump and the following impeller determines whole turbopump performance. In addition, low inlet pressure makes the flow to be cavitated not only at the inducer, but also at the impeller in real cases. Therefore, flow through an inducer and an impeller should considered simultaneously. In this study, LOX pump composed of an inducer and an impeller is analyzed by using commercial CFD code ANSYS CFX 13.0. Non-cavitating flow with high inlet pressure and cavitating flow with low inlet pressure are both simulated and head, suction performances are shown. Evolution of the flow and the cavitation by reducing cavitation number and effect of cavitation on pump performance are studied.

• The KSFM Journal of Fluid Machinery
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• v.13 no.1
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• pp.23-28
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• 2010

A draft tube which has impeller to elevate bottom water and spread it over surface of lake water, induces convective circulation of lake water, a Long-Distance Circulation (LDC). Circulation of lake water make stratified water mixed and enhance DO (Dissolved Oxygen) of bottom water. Circulation rate of water is determined by draft rate of the tube, which is dependent on design parameters of the draft tube system, i. e. dimension of impeller and diffuser, inclined angle of impeller, impeller shape, and rotational speed. In this study, change in draft rate and power consumption of circulation equipment was investigated numerically with changing impeller dimension, angle and rotational speed. It was found that flowrate of draft water was increased as the dimensions of draft tube and impeller, and rotational speed and inclined angle of impeller increased. The power consumption was also elevated with increasing parameter values, and final selection of parameter values was made to satisfy target flowrates and power consumption.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7878-7884
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• 2015

Marine sea water pump with impeller using carbon fiber block was developed to prevent the impeller corrosion by the salinity. A numerical analysis was carried out in order to optimize the impeller and volute design for marine sea water pump and to investigate the sensitivity of the related parameters(impeller thickness, surface roughness) using CFD commercial code. The impeller thickness is limited because of the weight. Since the impeller using the carbon fiber lights, the thickness which has a maximum efficiency can be used. The results show that the surface roughness leads to an 7% reduction in pump efficiency.