• 한국유체기계학회 논문집
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• 제3권4호
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• pp.38-43
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• 2000

Recently, KARI(Korea Aerospace Research Institute, Korea) and CIAM(Central Institute of Aviation Motors, Russia) have made an effort in developing a centrifugal compressor for a small gas turbine engine as part of a collaboration program. This compressor has been designed as a sub-component for an axial-centrifugal compression system for a small turbo-shaft engine aiming adiabatic efficiency higher than 0.81. The geometrical design requirement imposes restrictions to have high inlet hub-to-tip ratio and inlet swirl flow. In this study, the compressor has been designed using the generalized experimental data established from those compressors having pressure ratio of 3.7 to 5. From this generalized empirical correlation, desirable values of design parameters could be obtained. Subsequently, quasi-3D and 3D viscous flow analyses have been performed to ensure the adopted methodology. It is expected that the centrifugal compressor provides total pressure ratio of 4.89, corrected mass flow-rate of 1.64kg/sec, and adiabatic efficiency of 0.815 with inlet hub-to-tip ratio of 0.641. These relatively high total pressure ratio and inlet hub-to-tip ratio are the main distinctive features in this design. Besides, one of the main features of this centrifugal compressor is the adoption of a double-row bladed diffuser to effectively decelerate the transonic flow leaving the impeller. The compressor has been manufactured and will be tested in the near future.

• 대한기계학회논문집B
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• 제31권6호
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• pp.507-513
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• 2007

This study represents the temperature uniformity in catalytic converter. Present research model type is a monolithic catalytic converter. This type was been widely used for complying the regulations of pollutant emissions from automobiles. The mean experimental parameters are engine speed and ceramics monolith in the catalytic converter. The experimental test engine model used was the 124.1cc motorcycle engine. The experimental study using thermal imaging method shows the megaphone type model has larger effective area than the basic model. The rate of effective area in the basic model is about 8.9 % and the megaphone type model are 41.52 %, 34.60 %, 33.43 %, 25.43 %, 17.82 % according to the diffuser angle $4^{\circ}\;to\;8^{\circ}$. In conclusion, the megaphone type monolithic converter has higher efficiency of reducing the pollution with less noise compared to the basic shape. We believe this will be very important as a design guide of the advanced motorcycle.