• 설비공학논문집
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• 제15권1호
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• pp.50-58
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• 2003

An analytical study was carried out to investigate the performance of an oil pumping system of a variable speed compressor using a commercial CFD program. The simulations for the oil supplying system with the oil and air mixture were performed by varying compressor speed from 40 Hz to 90 Hz. Comparing the predicted with the measured data on the modified scroll compressor validated the simulation model. The predicted results were consistent with the test data with a maximum deviation of 12.8%. The oil flow rate significantly increased with a rise of compressor speed due to a higher oil flow rate from the swing pump and a greater centrifugal force on oil gallery.

• 설비공학논문집
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• 제12권7호
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• pp.674-679
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• 2000

The Sirocco fan performance and its three-dimensional flow characteristics were numerically predicted by STAR-CD software. Turbulent flow computations were performed using approximately 500,000 mesh points, and the performance results of two computational methods, transient analysis and quasi-static analysis were compared with experimental data. At present, our attention was focused on localizing the three-dimensional flow characteristics of the Sirocco fin, especially the structure of the secondary flow in the scroll and the through-flow characteristics of the Sirocco fan blades. Also, for an optimization, the scroll passage was tilted with 10 degrees to change the flow characteristics and improve the performance of the Sirocco fan.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.346-350
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• 2000

In scroll compressors, there are two major noise sources. Sturctural path: excitation of the compressor housing by unbalance forces and forces generated by compression cycle. Gas cavity path: excitation of top cap by discharge gas pulsation. In this study, in order to analyze the radiated noise generated by the discharge gas pulsation, FEM/BEM model of the top cap is established. Measured pressure of discharge pulsation is introduced in the FEM model as the excitation and vibration response is calculated. Radiated sound pressure is then obtained by BEM method based on this vibration response. Results are compared with the measured data. It is shown that the trend of the noise radiation can be predicted in this approadch.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.840-844
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• 2003

A study for increase of fan flow rate by geometric modification has been conducted to decrease temperature rise of marine generator inner part. Through experiment of a real product, a performance curve for various flow resistances was obtained. Flow analyses for each cases were done by using commercial code-FLUENT and the results were very similar to experimental data (0.7% deviation at normal operating condition). Through flow analysis results for various design geometric modification, a scroll type fan was adopted as a best design geometry with 100Pa more pressure and 22% more flow rate than original fan.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권1호
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• pp.34-38
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• 1999

In order to develop a thin type ESP(Electrostatic Precipitator) for high efficient air-conditioner with low concentration of ozone generation, collecting electrode spacing should be narrower than that from Deutsch formula and minimizes discharge current in ionizer. In this paper, the effect of applied voltage on the precipitation efficiency and ozone concentration of scroll type ESP was studied. As a result, precipitation efficiency(one pass) was improved by about 30[%] from increment of collector voltage(3.5[㎸]). Precipitation efficiency was increased with increasing ionizer voltage. And after some point, the efficiency was saturated. At the point, voltage and ionizer current was 5.2[㎸] and 95$[\muA]$ per meter respectively. At these applied voltage conditions, ozone concentration was saturated about 0.01[ppm] after 3 hours in 23$[m^3]$ closed room test.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.70-77
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• 2004

Comprehensive investigation on the outlet's geometric shapes of a centrifugal blower with higher inlet resistance than an atmospheric pressure is carried out for improvements of its performance. Most unwanted behaviors of such blower are pulsating flows because of unbalance between inflows and outflows in a scroll casing. In order to reduce this undesirable phenomenon a triump is made for both the shape of outlet duct and an accessory structure inserted in the outlet port of the blower. The modification on the shape is concerned with the contraction of cross sectional area and the attached structure is for an intentional obstruction to cause a flow resistance. The details of the modification are examined for different cases and results. The methodologies for the work are performance evaluations including noise level and velocity measurements with PIV Consequently, the performance of improved system is close to that of the system operating with atmospheric pressure at the inlet.

• International Journal of Air-Conditioning and Refrigeration
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• 제9권2호
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• pp.44-50
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• 2001

The Sirocco fan performance and its three-dimensional flow characteristics are numerically prediction by STAR-CD. Turbulent flow computations are performed using approximately 500,000 mesh points, and the performance results of tow computational methods, transient and quasi-static flow analyses are compared with experimental data. In the present study, our attention is focused on the three-dimensional flow characteristics of the Sirocco fan blades and the secondary flow structure in the scroll. For a design optimization study, the scroll shape is titled by $10^\circ$ to modify the secondary flow structure, which yields some improvement of the fan performance.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.701-704
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• 2001

최근 카오스현상에 대한 연구가 지속적으로 이루어지고 있다 카오스 철상을 이용하여 많은 분야에서 다양하게 연구되고 있는바 본 논문에서는 1차원 CNN을 구성하여 하이퍼카오스 신호를 생성하고 하이퍼카오스 동기화에 기반을 둔 암호화 통신을 적용하여 구현하는데 초점을 맞추었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.705-708
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• 2001

최근 카오스현상에 대한 연구가 지속적으로 이루어지고 있다. 카오스 현상을 이용하여 많은 분야에서 다양하게 연구되고 많은 응용기술이 개발되고 있다. 본 논문에서는 1차원 CNN을 구성하여 하이퍼카오스 신호를 생성하고 하이퍼카오스 동기화 구현하는데 초점을 맞추었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.903-907
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• 2002

본 논문에서는 하이퍼카오스 회로에서의 비밀통신 방법을 제시한다. 하이퍼카오스 회로는 n-double scroll CNN 회로를 이용하였으며, 동일한 2개 또는 4개의 셀을 가진 n-double scroll 회로를 이용하여 송ㆍ수신부를 구성하고 이송ㆍ수신부 사이에 구동 동기를 이용한 동기화를 이루었으며, 상태 변수 $\chi$$_3$에 의한 비밀통신이 상태 변수 $\chi$$_2$,$\chi$$_1$에 의한 방법보다 우수함을 보였다.