• The KSFM Journal of Fluid Machinery
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• v.2 no.3 s.4
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• pp.59-66
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• 1999

In this study the effects of nozzle diameter on the performance characteristics for the tangential impeller-type water meter are studied experimentally. The nozzle is cut along the tangential direction of the inner case in the water meter. The nozzle shape is round and the number of nozzles used for the experimental study are 8. The performance characteristics are discussed for various nozzle diameters such as 3.1, 3.3, 3.5, 4.0, 4.5 and 5.0 mm. Among the tangential impeller-type water meters, the water meter with the nozzle diameter of 5.0 mm shows the least pressure loss and the instrumental error compared to the Korean Standards.

• The KSFM Journal of Fluid Machinery
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• v.2 no.3 s.4
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• pp.17-23
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• 1999

In the present numerical analysis, investigation of the effect of blade loadings from design shape on the slip factor variation was studied. Both the Eckardt radial bladed impeller and the backswept impeller were analyzed. In addition, a new design of the blade profile was arbitrarily attempted to generate a center-loading pattern in the original backswept impeller. Three dimensional compressible Navier-Stokes flow analysis with the Baldwin-Lomax turbulence model was applied to get the numerical slip factor at each impeller exit plane using the mass-averaging technique. The numerical slip (actors are in good agreement with the experimental ones and the Wiesner's slip factors deviate further from the numerical and experimental ones in both backswept impellers. Deviation angles and meridional channel loadings are found in no relation with the trend of change of the slip factor. Blade-to-blade loadings in midspan location are, however, found to have a direct relationship, especially at the sections where maximum loadings we to be expected. That information can be utilized in establishing an improved expression for slip factors in the future.

• The KSFM Journal of Fluid Machinery
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• v.11 no.4
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• pp.38-44
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• 2008

This paper describes the performance and internal flow characteristics of two-stage high pressure ring blower. Chamber-type test rig is designed and manufactured for the performance test of the ring blower. Detailed flow characteristics inside the impeller and casing are analyzed by three-dimensional numerical simulation. Throughout numerical simulation, non-uniform inflow to the impeller inlet and reverse flow are observed near the inlet duct of the blower. This non-uniform inflow makes various recirculation flow inside the casing with the complicated shape of casing. Low velocity region is locally formed near the both sides of impeller outlet due to the non-uniform inflow to the impeller, thus deteriorates the performance of a ring blower.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.43-44
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• 2005

The effect of break down of centrifugal pump due to entrained air has not been clarified yet. Thus, air-water two-phase flow experimental apparatus was installed to clarify the effect of break down. The performance results of a single-phase flow satisfied reappearance. Also, the heads coincided well impeller types.

• International Journal of Fluid Machinery and Systems
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• v.2 no.4
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• pp.426-430
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• 2009

In order to investigate the design method for a micro centrifugal compressor, which is the most important component of an ultra micro gas turbine, an impeller having the outer diameter of 20mm was designed, manufactured and tested. The designed rotational speed is 500,000 rpm and the impeller has a fully 3-dimensional shape. The impeller was rotated at 250,000 rpm in the present study. The experimental results of the tested compressor with the vaned and the vaneless diffusers were compared. It was found that the vaned diffuser attained the higher flow rate than the vaneless diffuser at the maximum pressure ratio. In addition the maximum pressure ratio was higher for the diffuser having a larger diffuser divergence angle at the high flow rate. These results were compared with those obtained by the prediction method used at the design stage.

• International Journal of Fluid Machinery and Systems
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• v.2 no.2
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• pp.172-178
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• 2009

This paper reports on an investigation (using RSM with commercial CFD software) of the performance characteristics of the impeller in a centrifugal pump. Geometric parameters of vane plane development were defined with the meridional shape and frontal view of the impeller. The parameters are focused on the blade-angle distributions through the impeller in a fixed meridional geometry. For screening, a $2^k$ factorial design has been used to identify the important design parameters. The objective functions are defined as the total head rise and the total efficiency at the design flow-rate. From the $2^k$ factorial design results, it is found that the incidence angles and the exit blade angle are the most important parameters influencing the performance of the pump.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.391-396
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• 2003

A cross-flow fan relatively produces higher dynamic pressure at low speed because a working fluid passes through an impeller blade twice and blades have a forward curved shape. The performance of a cross-flow fan is influenced 25% by the impeller, 60% by the rearguider and the stabilizer, and 15% by the heat exchanger. At the low flow rate, there exist a rapid pressure head reduction, a noise increase and an unsteady flow against a stabilizer and a rearguider. The purpose of this study is to investigate the reciprocal relation among each parameter Experiments are conducted to study the effects of a rearguider and a diameter ratio of impeller on the performance analysis of a cross-flow fan. Comparing with the rearguider of radial type, the Archimedes type shows excellent results for various diameter ratios.

• The KSFM Journal of Fluid Machinery
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• v.11 no.3
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• pp.36-42
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• 2008

In this paper, the performance characteristics of the impeller in a centrifugal pump were investigated using DOE(Design of Experiment) with commercial CFD software. Geometric parameters of vane plane development were defined with the meridional shape and frontal view of the impeller. The incidence angles and the exit blade angle were selected as main parameters using 2k factorial and the influences of selected design parameters were examined through the optimization process using RSM.

• The KSFM Journal of Fluid Machinery
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• v.14 no.2
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• pp.47-51
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• 2011

This paper describes the shape optimization of a blower impeller used for a refuse collection system. Two design variables, which are used to define the blade angles of an impeller, are introduced to increase the blower performance. A blower efficiency is selected as an object function, and the shape optimization of the blade angles is performed by a response surface method (RSM). Three-dimensional Navier-Stokes equations are introduced to analyze the internal flow of the blower and to find the value of object function for the training data. Relatively good agreement between experimental measurements and numerical simulation is obtained in the present study. Throughout the shape optimization, blower efficiency for the optimal blade angles is successfully increased up to 3.6% compared with that of reference at the design flow rate. Detailed flow field inside the turbo blower is also analyzed and discussed.

• Journal of Ocean Engineering and Technology
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• v.35 no.6
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• pp.446-456
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• 2021

To build an environment facility of a large-scale ocean basin, various detailed reviews are required, but it is difficult to find data that introduces the related research or construction processes on the environment facility. The current generator facility for offshore structure safety evaluation tests should be implemented by rotating the water of the basin. However, when the water in the large basin rotates, relatively large flow irregularities may occur and the uniformity may not be adequate. In this paper, design and review were conducted to satisfy the performance goals of the DOEB through computational numerical analysis on the shape of the waterway and the flow straightening devices to form the current in the large tank. Based on this, the head loss, which decreases the flow rate when the large tank water rotates through the water channel, was estimated and used as the pump capacity (impeller) design data. The impeller of the DOEB current generator was designed through computational numerical analysis (CFD) based on the lift surface theory from the axial-type impeller shape for satisfying the head loss of the waterway and maximum current velocity. In order to confirm the performance of the designed impeller system, the flow rate and flow velocity performance were checked through factory test operation. And, after installing DOEB, the current flow rate and velocity performance were reviewed compare with the original design target values. Finally, by measuring the current velocity of the test area in DOEB formed through the current generator, the spatial current distribution characteristics in the test area were analyzed. Through the analysis of the current distribution characteristics of the DOEB test area, it was confirmed that the realization of the maximum current velocity and the average flow velocity distribution, the main performance goals in the waterway design process, were satisfied.