연소기내에서 발생하는 다양한 연소 불안정 현상에 대한 고찰

서성현 한밭대학교 생산융합기술연구소 2004 생산융합기술연구소 논문집 Vol.4 No.1

육군 상담관의 상담 효과에 관한 고찰

서성현 한국보훈학회 2024 한국보훈논총 Vol.23 No.1

국방부에서 시행하고 있는 군 상담관 제도에 대해 상담이론을 적용하여 검토하였다. 야전부대 간부 및 병사 600명을 대상으로 군 상담관 제도에 대한 설문조사를 실시하였다. 본 연구는 군 상담관 제도에 대한 설문조사 자료 분석 결과와 외국군 적용 사례를 분석하여 우리 군의 군 상담관 제도에 대한 활성화 방안을 제시하였다. 연구결과를 종합하면 첫째, 일·이등병에 대한 체계적이며 지속적인 상담관리가 필요하다. 둘째, 제대별 도움배려장병 2~3%는 군 상담관에 의한 체계적인 관리가 보장되어야 한다. 셋째, 부대생활 부적응 장병에 대한 군 상담관의 집중 관리가 필요하다. 넷째, 야전부대에서 군 상담관의 역할이 병사들의 군 생활에 도움이 되지 않는다는 일부 의견에 주목하여야 한다. 다섯째, 군 상담관의 역할이 부대지휘에 도움이 되어야 한다. 군에서 요구하고 있는 군 상담관의 역할은 제대별로 복무부적응 장병을 식별하여 관련사항을 지휘관에게 보고하고, 도움배려장병을 상담하여 관리한다. 앞으로 군 복무부적응 장병을 조기에 식별하여 적응시키고 자살사고를 예방하는 데 군 상담관의 역할이 매우 중요하며 대대급까지 확대 적용할 수 있도록 발전되어야 할 것이다. This study is on the role of military counselors and the effect of their counseling. The study examined the military counseling system which is enforced by the Ministry of National Defense on counseling theory. The survey was conducted with 600 field unit officers and soldiers. The research suggested the activation plan of the military counseling system through the analyzation of the results of the survey and the cases of foreign troops. The results of the study are as follows; Firstly, a continuous and systematic counsel management is required for the private class of the military. Secondly, a systematic management should be guaranteed for 2~3% of officers and men who need special care of the military counsellor at each level of headquarters. Thirdly, the intensive care by military counsellor is necessary for the officers and men who could not adapt themselves to the surroundings in the barracks. Fourthly, special notes should be taken of the opinions that the role of the military counsellor is not helpful for the soldiers at the field forces. Fifthly, the role of military counsellors should be of help to the command of a troop. A role of the military counsellor which is required in the military is not only a reporting the related matters after identifying the officers and men who need special care at each level of headquarters but also taking care of them. Since the military counselor’s role becomes very important to prevent the suicide of the maladjusted soldiers with finding their danger and helping their adaptation in advance. We need to expand this system to the battalion level and develop it more in the future.

예 혼합 희박 연소기내의 연소 불안정 기구에 관한 연구

서성현 한밭대학교 생산융합기술연구소 2004 생산융합기술연구소 논문집 Vol.4 No.1

액체 로켓엔진 안정성 평가를 위한 압력 교란 장치 특성 연구

서성현,고영성,이광진,박성진,김형모,김종규,이수용 한국항공우주학회 2002 한국항공우주학회 학술발표회 논문집 Vol.- No.-

연소기내에서 발생하는 다양한 연소 불안정 현상에 대한 고찰

서성현 한밭대학교 생산융합기술연구소 2004 생산기반기술연구소 논문집 Vol.4 No.1

Combustion instability has a long history of observation in various different combustion systems. In the past, it attracted attention of researchers in liquid rocket engines and now in lean premixed gas turbine combustors. For each specific combustion system, pressure fluctuations measured during high frequency combustion instability detrimental to hardware presented many different characteristics. High frequency instability occurring in a lean premixed gas turbine combustor may be dominantly affected by a nonlinear relation between pressure oscillations and heat release rate fluctuations and gas dynamics plays a crucial role in determining and amplitude of a limit cycle for a liquid rocket thrust chamber. Combustion instability phenomena manifest their inherent nonlinear characteristics. One is a limit cycle and the other bifurcation described by nonlinear time series analysis.

기쁨의 신학에 기초한 대림절 성탄절 절기 교육프로그램 개발에 관한 연구

서성현 한국기독교교육정보학회 2023 기독교교육정보 Vol.- No.79

이 연구는 현대인들의 우울증과 불안장애가 증가하는 추세에서 교회학교가 어떤 역할을 해야 할지에 대한 고민에서 출발하였다. 교회에서조차도 우울과 불안이 증가하는 가운데 참 기쁨의 복음을 가르칠 수 있는 교회학교 교육프로그램이 필요했다. 현대사회의 우울과 불안을 극복하는 대안으로써 기쁨의 신학과 성서 속 기쁨의 서사를 바탕으로 한 대림절 성탄절 절기 교육프로그램을 개발하였다. 교육프로그램 개발은 ADDIE 모형에 따라 아홉 명의 연구원이 약 6개월 동안 수행하였으며, 세 지역에서 교사 세미나를 열어 교회학교 교사와 지도자를 대상으로 개발한 프로그램을 시연하였다. 시연 후 교육프로그램에 대한 만족도와 타당성을, 참석한 사람 중에 교회 대표자들과 미디어 자료를 구매한 사람을 대상으로 평가를 받았는데, 대체로 만족하고 기쁨의 신학을 가르치는 내용이 타당하다는 의견이 많았다. 연구 결과, 기쁨의 신학을 바탕으로 개발한 대림절 성탄절 절기 교육프로그램은 교사와 지도자에게 교육 현장에서 활용하기에 만족스러웠고, 교육 내용도 타당했다. 이 연구는 교회학교 교육을 위한 교육프로그램을 개발하는 과정과 개발연구의 제한점 등을 통하여 앞으로 교회의 절기 교육프로그램을 개발하거나 신학적 주제 중심 교육프로그램을 개발할 때 참고할 지침을 제공할 것을 기대한다. In the face of increasing trends of depression and anxiety disorders among modern people, this study developed an educational program for Advent and Christmas seasons based on the theology of joy. The program is designed to help church school teachers and leaders teach the gospel of true joy to their students. The program was developed using the ADDIE model and was evaluated by church representatives and those who purchased the media materials. The results showed that the program was satisfactory for teachers and leaders to use in the educational field, and the educational content was also valid. This study is expected to provide guidelines for the development of church season educational programs or theological theme-centered educational programs in the future.

예 혼합 희박 연소기내의 연소 불안정 기구에 관한 연구

서성현 한밭대학교 생산융합기술연구소 2004 생산기반기술연구소 논문집 Vol.4 No.1

Lean premixed combustion has been considered one of promising solutions for the reduction of NOx emissions from gas turbines. However, unstable combustion of lean premixed flow becomes a real challenge on the way to design a reliable, highly efficient dry low NOx gas turbine combustor. Contrary to a conventional diffusion type combustion system, characteristics of premixed combustion significantly depend on a premixing degree of combusting flow. Combustion behavior in terms of stability has been studied in a model gas turbine combustor burning natural gas and air. Incompleteness of premixing is identified as significant perturbation source for inducing unstable combustion. Application of a simple convection time lag theory can only predict instability modes but cannot determine whether instability occurs or not. Low frequency perturbations are observed at the onset of instability and believed to initiate the coupling between heat release rate and pressure fluctuations.

터보펌프 환경에서 가스발생기 연소특성

서성현,임병직,안규복,한영민,최환석 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-

고농도 과산화수소와 수소화물의 지속적인 반응에 대한 연구

서성현 한국수소및신에너지학회 2015 한국수소 및 신에너지학회논문집 Vol.26 No.3

The present paper discusses about noble idea on various reactions including hydrides, hydrogen peroxide and nano-sized metal powders, which do not emit toxic materials as well as carbon dioxide. Here in this paper, the very first-ever concept that heat energy can be generated from the direct reaction between sodium borohydride and hydrogen peroxide is presented. Sodium hydride as fuel can supply hydrogen reacting with oxygen provided by the decomposition of hydrogen peroxide solution. Solid sodium borohydride can be resolved in water and treated as liquid solution for the easy handling and the practical usage although its solid powder can be directly mixed with hydrogen peroxide for the higher reactivity. The thermodynamic analysis was conducted to estimate adiabatic reaction temperatures from these materials. The preliminary experiment on the reactions conducted using sodium borohydride powder and hydrogen peroxide water solution revealed that the self-propagating reaction can occur and that its reactivity increases with an increase of hydrogen peroxide concentration.

Investigation of Self-Excited Combustion Instabilities in Two Different Combustion Systems

서성현 대한기계학회 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.7

The objective of this paper is to characterize dynamic pressure traces measured at self-excited combustion instabilities occurring in two combustion systems of different hardware. One system is a model lean premixed gas turbine combustor and the other a fullscale bipropellant liquid rocket thrust chamber. It is commonly observed in both systems that low frequency waves at around 300Hz are first excited at the onset of combustion instabilities and after a short duration, the instability mode becomes coupled to the resonant acoustic modes of the combustion chamber, the first longitudinal mode for the lean premixed combustor and the first tangential mode for the rocket thrust chamber. Low frequency waves seem to get excited at first since flame shows the higher heat release response on the lower frequency perturbations with the smaller phase differences between heat release and pressure fluctuations. Nonlinear time series analysis of pressure traces reveals that even stable combustion might have chaotic behavior with the positive maximum Lyapunov exponent. Also, pressure fluctuations under combustion instabilities reach a limit cycle or quasi-periodic oscillations at the very similar run conditions, which manifests that a selfexcited high frequency instability has strong nonlinear characteristics.