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응축기 설계조건에서 R12, R134A의 압력강하 해석
우주식 (J. S. Woo ),라흐만 (Rahman ),최현근 (H. G. Choi ),정한식 (H. S. Chung ),정효민 (H. M. Jeong ) 한국동력기계공학회 2009 한국동력기계공학회 학술대회 논문집 Vol.2009 No.6
In designing of condensers, the prediction of pressure drop is very important to predict the heat transfer coefficient. Modeling of two phase flow, inside a horizontal tube using CFD analysis is difficult with available two phase model in Fluent because of its changing flow patterns continuously. In this paper presents the CFD analysis of two phase flow of refrigerants inside a horizontal tube of 1.2m length inner model diameters of 0.0125m respectively, is carried out using Homogeneous model under adiabatic condition. The considered refrigerants are R12 and R134a. The analysis is conducted at different temperatures and flow rates to evaluate the local frictional pressure drop. Using Homogeneous model, average properties are obtained for each refrigerants. Obtained pressure drop data is compared with separated flow models available in literature.
Numerical and Experimental Study on the Steam Ejector
S. Wibowo(위보워),M. Sq. Rahman(라흐만),J. S. Woo(우주식),H. M. Jeong(정효민),H. S. Chung(정한식) 한국마린엔지니어링학회 2009 한국마린엔지니어링학회 학술대회 논문집 Vol.2009 No.-
Ejectors are simple pieces of equipment. They are employed in the industry such as in refrigeration and air conditioning, desalination, petrochemical and chemical industry. The purpose of this paper is to reveal the complication of the flow and the mixing process in a steam ejector. Air was used as primary and secondary fluids here. In this experiment, the influence of nozzle exit positions was investigated. The result shows the static pressure distribution along the ejector wall is influenced by nozzle exit position. In this study CFD simulation were also undertaken. Standard k-epsilon, RNG k-epsilon, and Realizable k-epsilon were tested in CFD. The CFD results were validated with available experimental data. In this case the result shows that realizable k-epsilon model closer with experimental result than another models.
Experimental study on Vacuum evaporation by ejector of fresh water generator system
S. Wibowo(위보워),ZhenHua Zin(김진화),J.S. Woo(우주식),H. M. Jeong(정효민),H. S. Chung(정한식) 한국동력기계공학회 2009 한국동력기계공학회 학술대회 논문집 Vol.2009 No.11
담수와 시스템은 염수를 음용수로 만들기 위해 해수에 열을 가하는 형태로 설계된다. 본 논문에서는 진공 튜브 증발을 하는 한 가지 형태의 청수제조장치의 진공튜브내의 특성을 알아보았다. 담수에 필요한 열에너지는 증류법을 이용하여 비등점을 내릴 수 있다. 이 실험에서는 증발기로 보내는 물의 온도는 60~90로 제어하여 실험하였다. 이는 버려지는 저압의 스팀과 같은 에너지를 이용하여 담수화 시스템을 구성할 수 있다.
Pressure Features in 3_arm steel pipe in Reciprocating Hydrogen Compression System
M. Sq. Rahaman(라흐만),G. H. Lee(이경환),S. Wibowo(위보워),J. S. Woo(우주식),H. M Jeong(정효민),H. S. Chung(정한식) 한국마린엔지니어링학회 2009 한국마린엔지니어링학회 학술대회 논문집 Vol.2009 No.-
Compressing system is essential parts of hydrogen economy. High pulsation waveforms produced during hydrogen compression can be reduced by employing snubber in the system. There aresome pipes to flow hydrogen between snubbers. An experiment has been conducted to investigate the features of pressure in the pipe placed between snubbers in reciprocating compression system. The 32.6970 ~ 53.1210% pressure pulsation reductions are found with pressure losses 0.1092 ~ 1.4413% by experiment and detail of pressure are obtained by CFD analysis.