• 한국유체기계학회 논문집
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• 제13권1호
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• pp.23-28
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• 2010

A draft tube which has impeller to elevate bottom water and spread it over surface of lake water, induces convective circulation of lake water, a Long-Distance Circulation (LDC). Circulation of lake water make stratified water mixed and enhance DO (Dissolved Oxygen) of bottom water. Circulation rate of water is determined by draft rate of the tube, which is dependent on design parameters of the draft tube system, i. e. dimension of impeller and diffuser, inclined angle of impeller, impeller shape, and rotational speed. In this study, change in draft rate and power consumption of circulation equipment was investigated numerically with changing impeller dimension, angle and rotational speed. It was found that flowrate of draft water was increased as the dimensions of draft tube and impeller, and rotational speed and inclined angle of impeller increased. The power consumption was also elevated with increasing parameter values, and final selection of parameter values was made to satisfy target flowrates and power consumption.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.113-118
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• 2000

Centrifugal pump are widely used and the noise generated by these machines causes one of the most serious problems. In general, the centrifugal pump noise is often dominated by tones at BPF(blade passage frequency) and its higher harmonics. This is a consequence of the strong interaction between the flow discharged from the impeller and the cutoff in the casing. However, only a few researches have been carried out on predicting the noise because of the difficulty in obtaining detailed information about the flow field and casing effects on noise radiation. The objective of this study is to develop a prediction method for the unsteady flow field and the acoustic pressure field of a centrifugal pump, and to calculate the effects of small vanes that are attached in original impeller-splitter impeller. We assume that the impeller rotates with a constant angular velocity and the flow field around the impeller is incompressible and inviscid. So, a discrete vortex method(DVM) is used to model the centrifugal pump and to calculate the flow field. The force of each element on the blade is calculated by the unsteady Bernoulli equation. Lowson's method is used to predict the acoustic source. The splitter impeller changes the acoustic characteristics as well as performance. Two-splitter type impeller is good for acoustic characteristics.

• Current Research on Agriculture and Life Sciences
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• 제32권2호
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• pp.91-97
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• 2014

우리나라 농가용 도정기의 구조요인과 도정성능을 분석하기 위하여, 판매되고 있는 농가용 도정기 29개 모델을 이용하여 제현장치와 정미장치로 분류하였고, 각 장치별로 구조적 특징을 조사하였고 그 결과를 바탕으로 성능요인을 분석하였다. 제현장치는 임펠러 회전속도가 주요 구조적 요인으로 조사되었으며, 4,800 rpm의 임펠러 회전속도가 65.5%로 가장 많이 사용하고 있는 것으로 나타났다. 이 회전속도에서 탈부율이 99.45%로 가장 높게 나타났고, 현미동할립율이 가장 낮게 나타나 제현성능에 가장 좋은 임펠러의 회전속도는 4,800 rpm인 것으로 분석되었다(p<0.05). 정미장치는 로터 선속도가 주요 구조적 요인으로 조사되었으며, 2 m/s의 로터 선속도가 60.1%로 가장 많이 사용하고 있는 것으로 나타났다. 이선속도에서 도정수율이 75.07%로 가장 높게 나타났고, 유실곡비율과 싸라기율이 각각 0.02%, 7.06%로 가장 낮게 나타나 정미성능에 가장 좋은 로터의 선속도는 2 m/s인 것으로 분석되었다(p<0.05).

• 한국음향학회지
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• 제42권6호
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• pp.519-528
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• 2023

본 논문에서는 식기 세척기 내 원심펌프를 대상으로 수치적/실험적 연구를 통해 최적 설계를 수행하였으며 유량 및 소음 성능을 개선하고자 하였다. 먼저 대상 원심펌프의 특성을 실험적으로 분석하기 위해 펌프 성능시험기를 통한 유량 실험과 반 무향실에서의 소음 실험을 진행하였다. 원심펌프 회전에 따른 내부 유동 및 유동 소음 성능을 수치적으로 모사하기 위해 전산유체역학 기반의 Reynolds Averaged Navier-Stokes(RANS) 방정식과 Ffowcs Williams and Hawkings 방정식을 지배 방정식으로 수치해석을 수행하였다. 실험 결과와의 비교를 통해 수치 기법의 유효성을 검증하였으며, 검증된 수치 기법을 활용하여 원심펌프 내 임펠러 형상에 대한 최적 설계를 수행하였다. 수치 기법의 활용을 통해 최적 설계된 임펠러의 개선된 유량 성능을 수치적으로 확인하였으며, 유동장 분석을 통해 임펠러 형상 각도 변화에 따른 유동 특성 변화 및 개선을 확인하였다. 또한, 시제품 제작 및 실험을 통해 개선 유량 성능을 검증하였으며, 팬 법칙에 의거하여 동일 유량에서 소음 수준이 감소함을 확인하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1999년도 유체기계 연구개발 발표회 논문집
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• pp.61-68
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• 1999

We have measured pressure distributions within the diffuser and pressures at the inlet and outlet of the compressor in orde to match impeller and low-solidity diffuser of 500RT centrifugal refrigerant-compressor which has been developed in LG Cable Ltd. Modified Stanitz equation is used to predict the measured data by tuning several parameters and then is validated. Using the validated parameters and modified Stanitz equation, we have obtained data necessary to design the diffuser.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.159-160
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.157-158
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• 2010

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.696-701
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• 2001

The performance and the internal flow of the impeller of the centrifugal chiller compressor with refrigerant R12 as working fluid were studied numerically, using CFD code, CFX-Tascflow, which is commercially available. In this numerical study, the thermodynamic and transport properties of the refrigerant gas were generated by the property program of NIST and linked with main program to extend the capability of the code to refrigerant gases. Numerical study was applied to several mass flow rates near the design mass flow rate at constant rotating speed. Overall performance and flow characteristics of the impeller at impeller exit were investigated. The results were physically reasonable and showed good agreement with experimental measurement at the design flow rate.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.801-806
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• 2001

The objective of present study is to find the interaction between volute and impeller of the centrifugal turbomachinery with rectangular cross-sectional volute. Flow measurement were taken in shrouded impeller with 12 backward type blades by using a five-hole pressure probe. The measurements are carried out in 7 flow rate, respectively. Primary function of a centrifugal turbo machinery volute is to serve the flow from the impeller and diffuser to pipe system. For the off-design conditions, Influence of pressure distortion was shown by these measurements. As a result, It has caused the decrease of total efficiency of centrifugal turbomachinery. We have also taken data to design volute by these measurements.

• 동력기계공학회지
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• 제13권6호
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• pp.82-87
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• 2009

LDV measurements were conducted on the planes between impeller blades of torque converter. The flow fields are extremely complex because they contain unsteady viscous three-dimensional flows. Besides of their complexity, the difference in rotor speeds between the impeller and turbine compound the flow effects. The good spatial resolution of the LDV allows measurements of the instantaneous flow structures within the impeller passage, yielding valuable information about the production automotive torque converter in realistic operating conditions. It was found that the mass flow rates are strongly related with the internal flow characteristics of torque converter.