• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.10
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• pp.3272-3281
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• 1996

The flow analysis method which had been developed for the numerical calculation of 3-dimensional, incompressible and turbulent flow within an axial compressor was extended to the flow field within centrifugal impeller. In this method based on the SIMPLE(Semi Implicit Method Pressure Linked Equations) algorithm, the coordinate transformation was adopted and the standard k-.epsilon. model using wall function was used for turbulent flow analysis. The calculated flow fields have agreed very well with measurement results. Especially, 3-dimensional and viscous flow characteristics including secondary flows, jet-wake flow and decreased pressure rise along impeller passage, which can't be predicted by inviscid Q3D calculation were predicted very reasonably.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.6
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• pp.804-809
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• 2007

In order to provide reliability. reproducibility. objectivity of solid particle separation performance test on marine centrifugal purifier, an investigation had been done on solid test dusts. test standards and designation of a definite standard test dust In test specifications or standards. ISO 121031-1 A2 test dust is the best test particle to meet commercial and military fuel oil and lube oil requirements on marine standards.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.627-632
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• 2000

Developing turbulent flows in a rotating 90 degree bend with square cross-section were measured by a hot-wire anemometer. The six orientation hot-wire technique was applied to measured the distributions of 3 mean velocities and 6 Reynolds stress components. Effects of Coriolis and centrifugal forces caused by the curvature and rotation of bend on the mean motion and turbulence structures were experimentally investigated Productive addition of Coriolis and centrifugal forces to the outward radial direction in the entrance region of bend increases the secondary flow intensity according to the rotational speeds. However, after 45 degree of bend, centrifugal force due to the rotation of bend may promote the break down of counter rotating vortex pair into multi-cellular pattern, thereby decreasing the production rate of turbulence energy and Reynolds stresses.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.10
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• pp.1296-1309
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• 1999

A three dimensional compressible Navier-Stokes code is developed to analyze flowfields and performance of a vaned diffuser in a centrifugal compressor. It employs scalar implicit approximate factorization, finite volume formulation, second order upwind differencing and a two-equation $q-{\omega}$ turbulence model based on the integration to the wall. Pressure recovery and loss coefficients of a vaned diffuser are evaluated using a developed computer code. The simulated three dimensional flows show how through flow structure affects pressure recovery performance and loss coefficients of a vane for design and off-design inlet flow angles. Development of complex three dimensional flow over the inlet region and leading edge are very influential to the overall flow and performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.645-645
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• 2009

In many practical applications of the centrifugal fan, the impeller-diffuser interaction noise is considered as a main source of fan noise. The housing for an electric motor is also expected to play an important role on noise propagation because of its complicated configuration. This study investigates the impeller-diffuser interaction noise and its sources by computing three-dimensional, incompressible flow field of the centrifugal fan in motor housing. The effect of motor case on fan noise characteristic is then investigated using the Brinkman penalization method, while the noise source associated with impeller-diffuser interaction is mathematically modeled. It is found that the present methodology combined with mathematical description of noise source provides a fairly good agreement with the experimental results, indicating that the motor housing has significant effect on noise characteristics. Finally, aeroacoustic noise prediction for various impeller-diffuser blade count ratios is conducted for noise reduction.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.5
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• pp.516-523
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• 2008

Centrifugal turbo blower is requested highly efficiency and low noise in FCEV, but the noise generated by this machine causes of the most serious problems in the NVH performance. In general, centrifugal turbo blower is dominated by mechanical noise and aerodynamic noise. Mechanical noise is generated by rotation of the bearing, misalignment and unbalance. And aerodynamic noise is generated by the strong intersection between the flow discharged from the impeller and the cut-off in the casing. The first object of this study is to comprehend a noise property of the blower through the noise test. And, second object is to bring up the method that can reduce blower noise.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.623-626
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• 2002

The object of present study is to find the flow characteristics of centrifugal turbomachinery according to the volute shape change. The experiments were carried out for two model; volute-A designed by free vortex conditions and volute-B designed for use in high mass flow rate conditions using the volute-A test results, Flow measurements were taken in shrouded impeller with 12 backward type blades by using a five-hole pilot-tube and carried out in 4 flow rate, $Q/Q_d\;=0,43,\;1.0,\;1.27,\;1,47$, respectively, For volute-B, we found that pressure distribution was more uniform at high flow rate and from $Q/Q_d\;:\;0,43\;to\;Q/Q_d\;:\;1,20$, losses decreased and efficiency increased compare with volute-A.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.639-642
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• 2002

A tubular centrifugal fin is designed by using various methods of analysis and design. A preliminary design method based on empirical optimum curves for centrifugal fin is used to determine the geometric parameters for tubular centrifugal fan. And, Quasi-3D streamline curvature duct-flow analysis is used to provide the primary position of streamlines and spanwise distribution of flow angle f3r generation of blade geometry based on S1 surface. Three-dimensional CFD solution then is obtained to optimize the blade design. Constriction of flow path in the region of impeller, backward swept blade, and central cone, which are introduced to improve the design, successfully remove or suppress the vortices downstream of the impeller.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.6
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• pp.685-692
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• 2006

In a general centrifugal pump, if it is operated in a two-phase flow the activity of the impeller usually degrades and occasionally losses its function. However, the effect of break down of centrifugal pump due to entrained air has not been clarified yet. This paper shows the air-water two-phase flow characteristics of closed type and semi-open type impellers. In a sing1e-phase flow, closed-type impeller has higher efficiency and head. But in air-water two-phase flow semi-open type impeller's rates of decreases of efficiency and head are decreased.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.89-94
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• 2002

A commercial CFD code is used to calculate the 3-D viscous flow field within the centrifugal pump impeller. Design conditions are changed by impeller inlet(9.3mm, 12.2mm) and outlet breadth(6.65mm, 6.85mm). Numerical calculation was performed by changing flow rate from 8 to 26m$^{3}$/hr. Computation results shows that total head is increased at the larger inlet and outlet breadth than the others. And when the flow rate is increasing, the total head was decreased. The maximum efficiency of pump is shown at the design flow rate(16m$^{3}$/hr). In this study shows that the calculated results are good agreements with analysis results of design condition.