• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3722-3730
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• 2015

The performance improvement of a small centrifugal compressor for waste water treatment has been conducted by the design change of vaneless diffuser and volute casing. Existing two compressors use a common impeller, but the width and length of the vaneless diffuser and the cross-sectional shape of the volute casing are different, respectively. Based on the experiment of the existing two compressors and their CFD results, the design of the vaneless diffuser and the volute casing has been changed. It was found that the strength of the interaction among the volute tongues, the vaneless diffusers and the impellers of two existing/one improved compressors, was affected by the cross-sectional area and inlet radial length of the volute casing including system losses' change. The efficiency of the impeller with one existing design was increased as the decrease of the width of the vaneless diffuser, but losses at the diffuser were accumulated. In conclusion, approximately 2.88%p efficiency increase at the design point of the new compressor with the improved design has been confirmed by CFD analysis results.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.83-90
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• 2001

Experimental and numerical investigations of the off·design performance of a simple channel-wedge diffuser in a small centrifugal compressor are presented. Surge and choke conditions as well as design point are considered using somewhat limited range of experimental data and also supplementary 3D CFD results. Some critical meanline design parameters' behavior is investigated numerically, to render the basis for improved modelings in the meanline performance prediction.

• 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.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.91-98
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• 2001

As the second part of the author's study, off-design behavior of the design and performance parameters in the low-solidity cascade diffuser in a centrifugal compressor is investigated. The experimental flange-to-flange compressor map serves the validity of application of the present CFD work to the detailed investigation of the low-solidity cascade diffuser. Some meanline design and performance parameters as well as three-dimensional internal secondary flow fields are studied when the flow rate is changed from deep choke to stall.

• The KSFM Journal of Fluid Machinery
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• v.3 no.1 s.6
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• pp.43-50
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• 2000

Upgrade development of a high pressure ratio centrifugal compressor in marine engine turbochargers is presented. A new matched operating point at increased speed of rotation was determined through system cycle analysis using the exisitng test data of turbine performance. Under some severe restrictions for geometric parameters, the state-of-the-art methods of both aerodynamic design and CFD analysis were applied, in which only an impeller, a vaned diffusor and some part of casing wall were modified. Prototype hardware was fabricated and assembled for system performance tests. Excellent performance in pressure ratio and efficiency was obtained over whole speed region. Reduced surge and choke margin was, however, observed at design speed of rotation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.129-134
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• 2005

This paper describes the influence of geometric parameters on the noise generation from a centrifugal compressor. From the analysis of noise measurements, it is observed that Blade Passing Frequency noise related to the rotating impeller is more important, and it is focused on the comparison of this discrete frequency noise according to the shape change. Navier-Stokes solver is used to simulate the flow-field of the impeller and the vaned diffuser, and time-dependent pressure data are calculated and Fourier-transformed to perform the near-field noise prediction. The effects of various geometry design variables such as the gap between the impeller and the diffuser, impeller shape variations on the near-field noise distribution are investigated.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.807-812
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• 2001

The effects of casing shapes on the interaction of the impeller and volute in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the compressor with circular and single volute casings from inlet to discharge nozzle. In order to predict the flow pattern inside the entire impeller, vaneless diffuser, and casing, calculations with a multiple frame of reference method between the rotating and stationery parts of the domain are carried out. For incompressible turbulent flow fields, the continuity and three-dimensional time-averaged Navier-Stokes equations are employed. To predict the performance of two types of casings, the static pressure and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.120-125
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• 2001

The effects of various vaned diffuser configurations, such as throat area ratios and rectangular and conical cross-section shapes. to the performance of a small-size turbo-compressor are studied. Numerical analyses were carried out for the region of diffuser and casing only. The pressure recovery coefficient was calculated to estimate the performance of the diffuser, and then compared with the measured data. Results show that the shapes and the throat area ratios of the diffuser strongly influence on the performance of a turbo-compressor.