• International Journal of Air-Conditioning and Refrigeration
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• 제10권1호
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• pp.19-30
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• 2002

This paper addresses characteristics of compressible flow dynamics inside a pipe with an accumulator and an inlet orifice. It also presents a simple but stable numerical method associated with the accumulator-orifice calculation. In particular, a focus is given to developing a method of finding an optimum design of the accumulator-orifice system (i.e., the accumulator size and the throttle resistance) that gives the most effective dissipation of the water-hammering problem. It is found that there exists indeed an optimum set of parameter values for the most effective dissipation of the wave energy.

• 한국자동차공학회논문집
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• 제12권2호
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• pp.197-204
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• 2004

An accumulator in hydraulic systems stores kinetic energy during braking action, and then that controls hasty surge pressure. An energy recovery system using accumulator seems to be advantageous for ERBS due to its high energy density. This study suggests a method to decide suitable accumulator volume for ERBS. The method is based upon energy conservation between kinetic energy of moving inertia and elastic energy of accumulator. The energy conversion was analyzed and a simple formula was derived. Also accumulator tests were conducted for different load mass and motor speed. A series of test work were carried out in the laboratory and the dynamic characteristics of the hydraulic motor system, such as the surge pressure and response time, were investigated in both brake action and acceleration action and these results show that the proposed design is effective for decision accumulator volume in ERBS.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.15-21
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• 2001

An accumulator in hydraulic systems stores kinetic energy during braking action, and then that controls hasty surge pressure. An energy recovery system using accumulator seems to be advantageous for ERBS due to its high energy density. This study suggests a method to decide suitable accumulator volume for ERBS. The method is based upon energy conservation between kinetic energy of moving inertia and elastic energy of accumulator. The energy conversion was analyzed and a simple formula was derived. A series of computer simulation was done to verify effectiveness of the formula. The results of the simulation work were compared with those of experiments and these results show that the proposed design is effective for decision accumulator volume in ERBS.

• 한국공작기계학회논문집
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• 제11권1호
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• pp.104-113
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• 2002

An accumulator in hydraulic systems stores kinetic energy during braking action and then that controls hasty surge pressure. An energy recovery system using accumulator seems to be advantageous far ERBS due to its high energy density. This study suggests a method to decide suitable accumulator volume far ERBS. The method is based upon energy conservation between kinetic energy of moving inertia and elastic energy of accumulator. The energy conversion was analyzed and a simple formula was derived. A series of computer simulation was done to verify effectiveness of the formu1a. The results of the simulation work were compared with those of experiments and these results show that the proposed design is effective far decision of accumulator volume in ERBS.

• 대한전자공학회논문지SD
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• 제40권5호
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• pp.361-368
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• 2003

저전력 파이프라인 병렬 누적기를 사용한 새로운 고속 직접 디지털 주파수 합성기가 제안되었다. 제안된 파이프라인 병렬 누적기는 속도 향상과 전력 소모 감소를 위하여 파이프라인과 병렬 기법 모두를 사용한다. 같은 처리 속도를 가지는 4 파이프라인 누적기와 4 병렬 누적기에 비하여 2 파이프라인 2 병렬 누적기는 66%와 69%의 전력만을 소모한다 제안된 누적기는 더 낮은 클럭 주파수에서 더 작은 면적과 더 적은 전력을 소모하면서 같은 속도를 얻을 수 있다. 3.3V전원의 0.35um CMOS 공정을 사용하여 모든 회로의 모의 실험과 제작이 수행되었다.

• 소음진동
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• 제6권4호
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• pp.513-519
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• 1996

This paper is concerned with the bubble sound at the accumulator which is generated by the difference of the high pressure side and the low pressure side in the cycle of the refrigerator. The causes of the bubble sound generation are verified by the visualized test of the operating refrigerant flow at the accumulator and the measurements of the temperature and pressure. Two cases were tested, one with the accumulator has a orifice and the other with the accumulator hasn't a orifice. So that, it is presented the comparison of the bubble sound levels and spectrums in each cases. To predict the bubble sizes when they are generated, the linearized equation driven by Strasberg is used.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.973-978
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• 2001

Noise reduction has become a major issue of the manufacturing industry. This paper describes the reduction of noise and vibration of rotary compressors. Empirical design for the present strap of the accumulator has been considered to be sufficient for the constraint of the accumulator resonance modes without thorough study. Recently, however, some researchers found out that the accumulator contributes considerably to the sound propagation. In this paper, the contribution of accumulator to the noise propagation is investigated through sound measuring experiments by checking the directivity of the noise. And, experimental modal analysis results show that frequencies of some resonance modes of the accumulator coincide with the highest peaks on sound spectrum. To demonstrate the reason for those resonance modes, a finite element analysis is conducted. Normal mode analysis of the finite element model of the rotary compressor shows the mechanism of the accumulator resonance modes.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.641-647
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• 2004

Characteristics of the high frequency pulsatile flow have been investigated experimentally to understand the flow phenomena in the hydraulic system. The accumulator in high frequency hydraulic system but that is not effective all frequency zone. Therefore, a hydraulic damper used with accumulator is suggested to reduce the high frequency pulsatile where the accumulator is not effective. The pulsating pressure obtained by Pressure measurement system are analyzed to power spectral density distribution. According to the variations of pump input pressure and actuator acceleration frequency, the pressure is measured with or without an accumulator or pulsatile damper The amplitude of pressure with damper is very lower than those without accumulator or damper due to absorbing function of damper. As the frequency of actuator acceleration is increased, the effect of damper becomes very important to decrease the amplitude of pulsatile Pressure waveform with high frequencies.

• 설비공학논문집
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• 제13권5호
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• pp.388-397
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• 2001

This paper addresses characteristics of compressible flow dynamics inside a pipe with an accumulator and an inlet orifice. It also presents a simple but stable numerical method associated with the accumulator-orifice calculation. In particular, a focus is given to developing a method of finding an optimum design of the accumulator-orifice system (i.e., the accumulator size and the throttle resistance) that gives the most effective dissipation of the water-hammering problem. It is found that there exists indeed an optimum set of parameter values for the most effective dissipation of the wave energy.

• 항공우주기술
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• 제7권1호
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• pp.8-14
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• 2008

항공기 휠브레이크용 축압기에 대하여 기본적인 특성을 조사하였다. 휠브레이크용 축압기는 주기시 제동유압을 유지하고, 비상시 휠브레이크에 유압을 공급한다. 휠브레이크용 축압기의 설계요구조건을 분석하고, 이를 토대로 설계에 필요한 기본 치수를 결정하였으며, 실린더와 브레이크 컨트롤 모듈로 구성된 축압기의 상세 구성요소와 기본 형상을 제시하였다. 또한, 예비 설계를 위하여 정적구조해석을 NASTRAN/PATRAN으로 수행하였다.