• International Journal of Air-Conditioning and Refrigeration
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• 제15권3호
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• pp.114-121
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• 2007

In this study, a modified reverse flow type, one of the triple effect absorption cycles, is studied for performance improvement. The cycle simulation is carried out by using EES(Engineering Equation Solver) program for the working fluid of $H_2O/LiBr$ solution. The split-ratios of solution flow rate, UA of each component, pumping mass flow rate of solution are considered as key parameters. The results show that the optimal SRH (split ratio of high side) and SRL (split ratio of low side) values are 0.596 and 0.521, respectively. Under these conditions, the COP is maximized to 2.1. The optimal pumping mass flow rate is selected as 3 kg/s and the corresponding UAEV A is 121 kW/K in the present system. The present simulation results are compared to the other literature results from Kaita's (2002) and Cho's (1998) triple effect absorption systems. The present system has a lower solution temperature and a higher COP than the Kaita's modified reverse flow, and it also gives a higher COP than the Cho's parallel flow by adjusting split ratios.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.472-473
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• 2008

Flow boiling in parallel microchannels has received attention as an effective heat sink mechanism for power-densities encountered in microelectronic equipment. the bubble dynamics coupled with boiling heat transfer in microchannels is still not well understood due to the technological difficulties in obtaining detailed measurements of microscale two-phase flows. In this study, complete numerical simulation is performed to further clarify the dynamics of flow boiling in microchannels. The level set method for tracking the liquid-vapor interface is modified to include the effects of phase change and contact angle. The method is further extended to treat the no-slip and contact angle conditions on the immersed solid. Also, the reverse flow observed during flow boiling in parallel microchannels has been investigated. Based on the numerical results, the effects of channel shape and inlet area restriction on the bubble growth, reverse flow and heat transfer are quantified.

• Archives of Plastic Surgery
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• 제46권1호
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• pp.84-87
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• 2019

With the recent development in microsurgery, the use of a perforator flap has been widely implemented. If the length of the ALT flap pedicle is insufficient despite adequate preoperative planning, pedicle length extension is necessary. We planned for a reverse ALT free flap using the distal vessel of the descending branch for pedicle length extension in the case of ALT perforator branch originating from the proximal portion of the descending branch. For the management of venous congestion, the distal venae comitantes were anastomosed to the proximal venous stump in an antegrade manner, successfully resolving the venous congestion. Modified reverse-flow ALT free flap, wherein the venae comitantes are anastomosed to the proximal vein stump, is a good option that allows for relatively simple pedicle extension within the same operative field when securing an adequate pedicle length is difficult because of the origin of the perforator from the proximal descending branch, unlike the initial surgical plan.

• 전기학회논문지
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• 제56권8호
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• pp.1373-1381
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• 2007

This paper presents a graphical windows-based software for the education and training of transmission network charge. The motivation for the development of the simulator is to provide students with a simple and useable tool for gaining an intuitive feel for transmission network charge. The developed simulator consists of the main module (MMI, GUI), the power flow module (PF), the power flow tracing module (PFT), and usage cost DB module (UCD). Each module has a separate graphical and interactive interfacing window. The developed simulator provides with two power system analysis methods (i.e., DC-PF and Modified DC-PF) and supports the PSS/E input data format to load input data of power system. Also, power flow tracing can be calculate using four methods such as "Felix Wu", "Modified Felix Wu", "DCLF ICRP", and "Reverse MW mile". Results of calculation for transmission usage cost are displayed and compared on the window through the table and/or chart. Therefore, the developed simulator can be utilize as a useful tool for effective education and training of transmission network charge.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 하계학술발표대회
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• pp.186-186
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• 2005

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.43-48
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• 2001

Combustor design technique is established by reverse engineering of existing combustor and applying heat & mass balance equations for the combustion process. The ratio of entrained air for each air slot is found to be almost proportional to the area ratio from the result of numerical simulation. The shape of the combustor is modified by the numerical analysis to get circumferentially uniform flow inside the combustion chamber required for the flame stability.

• 전기학회논문지
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• 제62권1호
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• pp.29-36
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• 2013

This paper deals with the analysis of the customer voltage characteristic in distribution system interconnected with large scale PV system. There would be many power quality issues which are caused by reverse power flow of PV system interconnected with distribution system. In order to analyze the effect of PV system on the customer voltage, detailed modeling method of distribution system and modified modelling method of PV system are proposed using PSCAD/EMTDC in this paper. So far, less than dozens KW of PV system can be simulated with the existing modelling method. Therefore, a new modeling method which can simulate the large scale PV system is proposed by considering the relationship equation on the phase and voltage in the current control algorithm. From the simulation result of proposed modelling method, it is confirmed that an optimal operation method in distribution system is suggested by analyzing the effect of PV system on customer voltage.

• 한국정밀공학회지
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• 제26권5호
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• pp.87-95
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• 2009

This research introduces the efficient modeling and manufacturing method using reverse engineering combined with rotational simulation of a pair of screw and mill-turn machining realized a proposed NC program. Because previously developed model had insufficient flow measuring accuracy, we considered that matter in the aspect of method of modeling and performance test. For that reason we modified the modeling which could minimize a gab between male and female screw, and developed precise tester which consists of constant tank, flowmeter and load cell, etc., and then conducted the test for defining characteristic and accuracy of flowmeter and repeated same test 5-times. Consequently we could obtain satisfied measuring accuracy and reproducibility indicated in the catalog of master model. Hence we give our conclusion as to the validity of developing accurate screw type flowmeter using the proposed process such as reverse engineering, mill-turn machining and precise performance test.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.201-203
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• 2006

This paper presents a graphical windows-based software for the education and training of the transmission network use of system charge. The developed simulator consist of the main module(MMI,GUI), the power flow module(PF), the power flow tracing module(PFT) and management of usage cost DB module(UCD). Each module has a separate graphical and interactive interfacing window. To have effective education for transmission network use of system charge, the developed simulator are provided with two power system analysis methods. Input data of power system can use the format of PSS/E input data. Also calculation of power flow tracing are provided with four methods such as "Felix Wu","Modified Felix Wu", "DCLF ICRP" and "Reverse MW mile". Results of calculation for usage cost are shown on the window through the table or chart. Therefore user can confirm the detailed differences of results from each calculation method.

• 한국컴퓨터정보학회논문지
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• 제1권1호
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• pp.105-128
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• 1996

소프트웨어의 전체 비용 중에서 유지보수 비용이 절반 이강을 차지하고 있기 때문에, 이 비용을 줄이기 위한 도구가 필요하다. 유지보수를 위한 공학적인 기법들 중에서 역 공학은 원시 코드로부터 설계 정보를 추출하고 원시 코드를 다른 형태 혹은. 좀 더 추상화된 형태로 표현하는 과정이다. 본 논문에서는 역 공학 기법을 적용하여. 기존 COBOL 프로그램으로부터 프로그램들 간의 호출 관계. 프로그램 내의 논리 구조와 프로그램의 자료 흐름에 대한 정보를 추출하는 방법에 대해서 제안하고 회복된 설계 정보로부터 프로그램 구조조도와 모듈 구조도를 생성하는 방법에 대해서 제시한다. 원시 코드로부터 정확하게 생성된 구조도는 유지보수 자가 프로그램을 전체적으로 혹은, 구체적으로 이해하도록 지원하는 중요한 정의가 될 것이다. 또한. 유지보수 자가 프로그램을 재분석할 때 혹은 다른 유지보수 자들이 그 프로그램을 분석할 때. 명확하게 수정된 구조도는 유지보수 자들에게 프로그램을 더욱 쉽게 이해하도록 지원하게 될 것이다.