• The Korean Journal of Rheology
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• v.10 no.1
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• pp.1-6
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• 1998

액체와 액체를 교반할 경우 혹은 두가지 이상의 상이 함께 반응하는 화학공정의 경 우에서는 비상용성인 액체들을 난류조건하에 분산시켜 섞이게 한다. 부산계로 구성된 중합 반응기의 경우 분산입자의 크기는 최종제품의 생산성 및 품질에 큰 영향을 미치게 되므로 분산입자의 크기를 예측하는 것은 대단히 중요하다. 이러한 분산계에서 분산입자의 크기는 분산입자가 겪는 유동장에 의해 결정된다. 오일/오일 분산계로 이루어진 고분자 유탁액의 난류교반시 유동장은 종종 점성전단 부영역에 속하게 되는데 이경우의 분산입자의 크기를 예측하는 모델에 대한 연구는 별로 이루어지지않았다. 본연구에서는 오일/오일 분산계의 고 분자 유탁액에 대한 분산입자의 크기를 예측하는 모델식을 유체동력학적인 이론을 배경으로 하여 개발하였다. 개발한 모델식을 난류교반을 겪은 오일/오일 분산계를 거쳐 생산된 제품 인 내충격성 폴리스티렌으로 검증하여 모델식의 타당성을 입증하였다.

• 레미콘
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• no.1 s.70
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• pp.4-18
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• 2002

• Economic and Environmental Geology
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• v.44 no.2
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• pp.153-159
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• 2011

A comprehensive mechanistic model has been used to determine the flow pattern for gas-oil two-phase flow in pipes of petroleum production system. Depending on operational parameters, geometrical variables, and physical properties of the two phases, the two phases shows a specific flow patterns. For different parameters of the system, How pattern were compared for wide range of superficial velocities of oil and gas. In a variety of parameters, the inclinational angle and superficial velocities of oil and gas are the most dominant factors in determining the flow patterns for two-phase flow in pipelines. Other parameters such as pipe diameter and fluid properties have a limited effect on the change of flow patterns except for near transition. The mechanistic model is shown to be useful to determine the flow pattern in situations where either an experimental evaluation in a laboratory or reliable correlations are not available.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.7
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• pp.32-40
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• 2003

An experimental research has been carried out for flow visualizations of the shock wave/turbulent boundary-layer interaction control utilizing the aeroelastic flaps, Spark shadowgraphs, kerosene-lampblack tracings for the surface streakline pattern, and interference fringe patterns over a thin oil-film applied at the downstream of the shock interactions have been obtained , Effects of variation of the shapes and thicknesses of the flaps are tested, and all the results are compared to the solid-wall reference case without flow-control mechanism , From the qualitative observation of the variation of skin friction utilizing the interference fringe patterns over the silicone oil-film, a strong spanwise variation of the skin friction with a narrow and long region of separation has been noticed near the centerline behind the shock structure, which phenomenon demonstrate a strong three-dimensionality of the shock interaction flows, Influence of the shape of the cavity under the flaps to the shock interaction is also tested, and it is observed that the shape of the cavity is not negligible.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.495-503
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• 2017

Wax components can be precipitated when surrounding temperature decreases below wax precipitation temperature (WAT). WAT as well as pour point are important characteristics to evaluate the behavior of waxy oils. In this study, qualitative and quantitative evaluations of waxes in waxy model oils were presented after determining WAT and pour point. In case of anhydrous waxy model oils, ASTM D2500 may be most useful to determine WAT because of the transparent nature of model oils. With same apparatus, ASTM D97 is also applicable to determine the pour point of waxy oils in a serial determination. In case of emulsified model oils, however, it is difficult to measure WAT because of its opaque nature. This study employed FTIR spectroscopy to determine wax precipitation temperature and discussed the effect of emulsion state regarding the values of WAT. Further study would be needed to conclude the effect of water contents to WAT values in case of emulsified waxy oil.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.68-74
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• 2010

In this study, fluidized-bed pyrolysis has been conducted in order to recover the bitumen contained in the oil sand. Canada Alberta oil sand contains 11.9% of bitumen and the bitumen-derived heavy oil produced in fluidizedbed tends to be upgraded relative to the bitumen. The continuous operation has been performed using $N_2$ as a fluidization gas at 1 atm and $500^{\circ}C$ in a reactor of 170 cm height. The results showed 87.76% of bitumen conversion, where liquid products are 74.45% and gas products are 13.31%. $H_2$, $O_2$, CO, $CO_2$, $CH_4$, and NO and $C_1{\sim}C_4$ hydrocarbons in the gas products were analyzed by on-line gas analyzer and gas chromatography, respectively. The pyrolysis oil was analyzed by using proximate analysis, heavy metal analysis, SIMDIS, asphaltenes, and heating value. By SIMDIS analysis, naphtha was 11.50%, middle distillation was 44.83% and heavy oil was 43.66%. It was obvious that the pyrolysis oil was upgraded compared with bitumens.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.1
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• pp.29-37
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• 2011

PIV measurements of the velocity field, pressure field, vorticity, and turbulent intensity in the rear of curved section of an oil fence with current speed showed that the flow directions in the rear of flow boundary area were similar to those in the front of it. As the current speed increased, the patterns of pressure distribution were changed, and the turbulent flow became more irregular. CFD simulations under the same conditions as the PIV tests showed that the flow patterns of the wake were similar to those by PIV tests in speed of 0.3 m/s and less, but were distinctively deviated from those in 0.4 m/s due to the flexibility of the oil fence, which was not properly taken care of in CFD modeling.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.467-470
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• 2005

지구온난화 현상과 화석연료의 고갈에 대한 두려움 때문에 재생에너지에 대한 관심이 지속적으로 증가하고 있다. 이에 따라 대체에너지, 합성가스, 화학 원료, 오일 등으로 전환할 수 있는 바이오매스 활용에 대한 연구도 활발히 진행되고 있다. 바이오매스의 열화학적 전환 공정에는 열분해, 연소, 가스화 등이 이용되고 있다. 특히 열분해는 syringol, levoglucosan, guaiacol등의 고부가가치 물질들을 생산하기에 적합한 기술로 인정받고 있다. 본 연구에서는 국내에서 쉽게 구할 수 있는 톱밥, 폐목재 등의 바이오매스의 열화학적 전환 특성을 분석하였다. 사용된 바이오매스의 열분해 특성은 열중량 분석기 및 열천칭 반응기를 통해 분석하였으며 이를 통해 유동충 반응기(지름 0.2m, 높이 2m)를 설계 및 제작하였다. 반응온도 및 산소 농도가 증가할수록 levoglucosan 등의 고부가가치 물질들의 수율이 낮아지며 페놀류가 급격히 증가함을 알 수 있었다. 회재 성분이 높은 왕겨의 바이오오일 수율은 톱밥보다 $30\%$이상 낮게 나타났다

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.87-94
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• 2006

An experimental research program providing knowledge to measure two-dimensional skin friction variation over a certain region of model surface is presented. In the oil-fringe imaging skin friction(FISF) technique, local slope of a thin oil applied on a test surface is measured from the interference fringe patterns on the oil surface, and its information is then related to the applied shear over the oil by the thin-oil lubrication theory. The FISF technique has been applied for a separation flowfield ahead of a circular cylinder vertically mounted on a flat plate, and it has been found that the FISF skin friction results show good comparison with the other numerical/experimental data obtained for similar conditions. implying an applicability of the technique.

• Cement
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• s.162
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• pp.48-58
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• 2004