• 한국해양공학회지
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• 제33권1호
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• pp.42-49
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• 2019

Drilling mud was used once in the step of separating the gas and powder they were transported to a surge tank. At that time, the fine powder, such as dust that is not separated from the gas, is included in the gas that was separated from the mud. The fine particles of the powder are collected to increase the density of the powder and prevent air pollution. To remove particles from air or another gas, a cyclone-type separator generally can be used with the principles of vortex separation without using a filter system. In this study, we conducted numerical simulations of air-particle flow consisting of two components in a cyclone separator in a mud handling system to investigate the characteristics of turbulent vortical flow and to evaluate the collection efficiency using the commercial software, STAR-CCM+. First, the single-phase air flow was simulated and validated through the comparison with experiments (Boysan et al., 1983) and other CFD simulation results (Slack et al., 2000). Then, based on one-way coupling simulation for air and powder particles, the multi-phase flow was simulated, and the collection efficiency for various sizes of particles was compared with the experimental and theoretical results.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.3892-3901
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• 2021

The pressure drop of a moisture separator in a steam generator is the important design parameter to ensure the successful performance of a nuclear power plant. The moisture separators have a wide range of operating conditions based on the arrangement of them. The prediction of the pressure drop in a moisture separator is challenging due to the complexity of the multi-dimensional two-phase vortex flow. In this study, the moisture separator test facility using the air/water two-phase flow was used to predict the pressure drop of a moisture separator in a Korean OPR-1000 reactor. The prototypical steam/water two-phase flow conditions in a steam generator were simulated as air/water two-phase flow conditions by preserving the centrifugal force and vapor quality. A series of experiments were carried out to investigate the effect of hydraulic characteristics such as the quality and liquid mass flux on the two-phase pressure drop. A new prediction model based on the scaling law was suggested and validated experimentally using the full and half scale of separators. The suggested prediction model showed good agreement with the steam/water experimental results, and it can be extended to predict the steam/water two-phase pressure drop for moisture separators.

• Korean Chemical Engineering Research
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• 제55권2호
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• pp.201-213
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• 2017

물이 포함된 원유는 oil separator 를 거쳐 물이 제거된다. 본 연구의 목적은 공기-물-기름 3상 혼합물에 대한 3차원 oil separator 의 분리성능을 예측하기 위하여 Eulerian 전산유체역학(CFD: computational fluid dynamics) 모델을 개발하는 것이다. 비압축성, 등온, 비정상상태 CFD 모델식은 공기상을 연속상으로, 물과 기름상을 분산상으로 정의하며, 운동량 보존식은 항력(drag force), 양력(lift force), 다공성매체 저항력을 포함한다. 또한, 난류현상으로 standard k-${\varepsilon}$ 모델이 이용된다. 물과 기름 출구압은 oil separator 의 액위를 결정하는 중요한 인자이며, 정상운전상태 액위 25 cm를 맞추기 위하여 측정압은 각각 6.3 kPa, 5.1 kPa으로 결정되었다. 시간에 따른 공기, 물, 기름의 부피분율의 변화를 조사하였고, 정상상태에 도달하였을 때, 물과 기름상의 침강속도를 oil separator의 종축 길이에 따라 분석하였다. 본 연구에서 제시된 CFD 모델로부터 얻은 oil separator의 기름분리성능은 99.85%이며, 실험값과 거의 일치하였다. 비교적 단순한이 CFD 모델은향후 oil separator의구조를 변경하거나, 최적운전조건을 찾기위하여 유용하게사용될수있을 것이다.

• 한국가시화정보학회지
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• 제4권2호
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• pp.81-87
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• 2006

In this paper, we present flow patterns around and performance of an air-flow separator by using the numerical analysis. With this separator, particles of different density are to be separated by using the drag force from the air flow. The low-density particles are designed to be separated by using inhalation through holes on a rotating drum. To obtain the flow informations needed for determining the proper design parameters, we have performed numerical simulations by using a commercial code, ANSYS CFX. Various parameter set was tested and it was found that depending on the design of drums there exist critical parameter set regarding the attachment of light particles on the drum, which is prerequisite for the separation of materials. We present here the possibility of using the present design in separation of particles mixed in the clod for use in recycling.

• 한국환경과학회지
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• 제7권1호
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• pp.41-45
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• 1998

The feasibility of foam separation to remove protein in aquacultural recirculating water was investigated. From the results of batch foam separation on protein removal, superficial air velocity and initial protein concentration in bulk solution were found to be important operational factors In determining removal rates of protein. The protein removal rate by batch foam separation was proportionally increased with the superficial air velocity. Performance characteristics of continous foam separator were highly dependent upon the operating parameters of superficial air velocity, hydraulic retention time(HRT) and foam height. Removal effeciency of protein increases with increasing superficial air velocity and HRT, and independent on foam height. As DO concentration was increased with superficial air velocity, foam separator is also used for oxygen addition. It could be confinned that foam separator might offer better perspective for protein removal in aquacuitural recirculating water.

• Journal of Biosystems Engineering
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• 제9권1호
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• pp.22-33
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• 1984

Husk separator is an indispensable equipment in rice milling plants. However, any basic research on the designing and operating criteria of the husk separator have rarely been conducted in Korea. According to the survey results reported recently, grain loss occurs in the process of rice husk separation at custom rice milling plants in Korea and the performance of husk separator has also not been identified. With this regard this study was conducted with a typical commercial husk separator to investigate the effect of the operational factors such as feed rate, blower speed and opening ratio on the velocity distribution in the air duct and the performance of the separator. The results are summerized as follows: 1. The average wind velocity in the primary air duct increased linearly with the blower rpm and the size of air inlet port in both cases of double type and single type operations. 2. The coefficient of variation in the horizontal wind velocities in the primary air duct was the minimum when the opening ratio was 0.22 ($0.052m^2$ of air inlet port) in both cases of single type and double type operations regardless of the blower speeds used in this test. The average wind velocity at the upper part of air duct was greater by 2-5 m/s than the velocity at the bottom part in double type operation. In case of single type operation, however, the average velocity in the middle part was greater than the upper or bottom part when the opening ratio was greater than 0.74. 3. The relationship between the overall effectiveness of separation(Ed for double type and Es for single type) and the average wind velocity (Va) in the primary air duct was expressed in the following quadratic functions. $$Ed=-190.84+106.18Va-10.052Va^2$$ ($r^2$ = 0.97782) $$Es=-223.76+106.23Va-9.1935Va^2$$ ($r^2$ = 0.97029) The average wind velocity required to obtain the overall effectiveness of separation more than 80% ranged from 4.04 m/sec to 5.84 m/sec in case of double type operation, and from 4.70 m/sec to 6.20 m/sec in case of single type. 4. An optimum wind velocity can be obtained with an increase in the blower speed or the size of air inlet port as presented in Figure 8. There was a tendency that the faster the blower speed, the narrower the control range of the air inlet port. 5. The feed rates (1850kg/hr and 2100kg/hr) adopted in this experiment did not bring about a significant difference in both the overall effectiveness of separation and the power consumption. 6. The energy consumption increased cubically with the blower speed but linearly with the size of the air inlet port. On the basis of the results described in items 1, 3, and 6, it would be more economic to adjust the size of the air inlet port larger with a relatively low blower speed than to adjust the size smaller with a relatively high speed.

• 대한조선학회논문집
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• 제54권6호
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• pp.470-475
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• 2017

Since the intake air of gas turbine engine of marine purpose contains water particles, inertial separator for separating the air and water particles are provided. Saw type and wave type separator are now used to separate inflow water particle from the gas. In this paper, the design parameters of saw type separator are studied by numerical simulations. Using the commercial CFD program, Star-CCM+, Lagrangian-Eulerian method was used to perform the analysis of two phase flow of the mist in the air. This method solves Reynolds-Averaged Navier-Stokes equations in Eulerian framework for the continuous phase, while solves equation of motion for individual particles in Lagrangian framework. Lagrangian multiphase method was applied to monitor the particles of different sizes and shapes and to verify collision between particles by chasing particles. Water particles were injected through injectors located at the inlet of the separator and escape mode was used which assumes that the particles attached on the surface of inertial separator were removed from the simulation, effectively escaping the solution domain. Through the numerical computations with the inlet condition of constant water particle size in the wetness fraction of 85%, efficiency of eliminating the water particle and the pressure drop between the inlet and outlet were examined.

• 한국해양공학회지
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• 제28권4호
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• pp.280-287
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• 2014

In this paper, the numerical simulation of the gas-liquid flow in a cylinder cyclone separator is performed to investigate the flow characteristics using a commercial software, FLUENT, which solves the Reynolds-averaged Navier-Stokes(RaNS) equations. First, a single-phase flow with water in a gas-liquid cylinder cyclone(GLCC) separator is simulated and compared with the experiments(Farchi, 1990) and numerical simulations(Erdal, 1997). Then, the characteristics of the multi-phase flow for water-air, mud-only, and mud-air cases are discussed in the view point of the feasibilities for a mud handling system.

• 한국항공우주학회지
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• 제41권9호
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• pp.714-719
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• 2013

본 연구 대상 터보 프롭 항공기는 주어진 항공기 임무 수행을 위해 결빙 조건하에서도 운용이 가능하여야 한다. 동 연구에 적용된 터보 항공기의 공기 흡입구 계통은 정상 비행조건하에서 엔진 입구에 최대 전압력을 공급할 수 있도록 설계 및 검증이 되어야 할 뿐만 아니라 결빙조건하에서 생길 수 있는 얼음과 같은 입자가 엔진 흡입구 망으로 들어가서 엔진 화염꺼짐이나 엔진에 심각한 손상을 주지 않도록 하기 위한 관성분리기를 포함하도록 개발이 되어야 한다. 따라서 결빙 조건하에서 형상이 변하는 가변형상의 공기흡입구 조립체를 설계하고 설계 결과 확인을 위해 조립체에 대한 전산 유동 및 구조해석을 수행하였다. 이후 35% 축소형 모델을 제작하여 풍동시험을 수행하였다. 동 논문에서는 흡입구 조립체 개발과정에서 요구되는 공기역학적 설계, 잔산 유동/구조 해석 및 풍동 시험평가 결과를 기술하였다.

• International Journal of Air-Conditioning and Refrigeration
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• 제17권3호
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• pp.88-93
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• 2009

Lubricant oil is needed in air conditioning and refrigeration system because the compressor requires oil to prevent surface to surface contact between its moving parts, to remove heat, to provide sealing, to keep out contaminants, to prevent corrosion, and to dispose of debris created by wear. Thus, the oil separation in an oil separator is one of the most important characteristics for proper compressor operation. In this study, a gravity type of oil separator is used. Oil separation characteristics have been investigated for $CO_2$/PAG mixture in the range of oil concentration 0 to 5 weight-percent and the mixture temperature range of $0^{\circ}C$ to $15^{\circ}C$ at 50 bar and $70^{\circ}C$ to $90^{\circ}C$ at 80 bar. The results obtained indicate that the oil separation is increased with an increase in the oil concentration. It is also found that the oil separation in liquid state is increased with an increase in the mixture temperature while the oil separation in gas state is decreased.