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김현묵(Hyun muk Kim),배성훈(Seong hun Bae),박철현(Cheol hyeon Park),전혁수(Hyeok soo Jeon),김정수(Jeong Soo Kim) 한국추진공학회 2017 한국추진공학회지 Vol.21 No.1
A thermo-fluid dynamic analysis was performed through the numerical simulation of a missile canister. Calculation was made in a fixed analytical volume and fully evaporated water was used as a coolant. To analyze the interaction among the hot gas, coolant, and mixture flow, Realizable k-ε turbulence and VOF(Volume Of Fluid) model were chosen and parametric study was performed with the change of coolant flow rate. It could be found that the pressure on the canister top nonlinearly increased with the increase of coolant flow rate. Temperature and coolant distribution were closely related to the flow behavior in canister. Temperature on the canister bottom indicated a decrease being proportional to coolant flow rate in early times but after a specific time, the temperature increased with the tendency being reversed. In addition, the early part of temperature showed a fluctuating phenomenon because of the overall circulatory flow of mixture gas.
수치모사를 통한 가스-스팀 발사체계의 열유동과 탄의 운동성능 예측
김현묵(Hyun Muk Kim),배성훈(Seong Hun Bae),배대석(Bae Dae Seok),박철현(Cheol Hyeon Park),전혁수(Hyeok Soo Jeon),김정수(Jeong Soo Kim) 한국추진공학회 2017 한국추진공학회 학술대회논문집 Vol.2017 No.5
이상유동 모델과 동적격자계를 활용하여 탄의 사출관 내부의 열유동과 탄의 운동성능을 해석하는 수치모사를 진행하였다. 고온의 공기와 냉각제간의 상호작용 및 유동장을 해석하기 위해, Realizable k-ε 난류 모델과 VOF (Volume Of Fluid) 모델을 선정하고 냉각제 유량변이에 따른 수치 해석을 진행하였다. 해석결과, 사출관의 압력은 냉각제의 유뮤에 따라 큰 차이를 보였고, 냉각제량에 따라서도 각각의 차이를 보였다. 탄의 속도와 가속도의 변이는 압력에 종속하여 나타났다. Numerical simulations were carried out to analyze thermo-fluid dynamic and missile-motion performance by using two-phase flow model and dynamic grid system. To analyze the interaction among the hot gas, coolant, and mixture flow, Realizable k-ε turbulence and VOF(Volume Of Fluid) model were chosen and a parametric study was performed with the change of coolant flow rate. As a result of the analysis, pressure of the canister showed a large difference depending on the presence or absence of the coolant, and also showed a dependancy on the amount of coolant. Velocity and acceleration were dependent on the canister pressure.
Oleamide 및 아라미드 칩을 첨가한 NBR 고무재료의 내소음성 및 물성 연구
김현묵 ( Hyun Muk Kim ),이창섭 ( Chang Seop Lee ) 한국고무학회 2006 엘라스토머 및 콤포지트 Vol.41 No.2
내소음성과 내균열성을 가진 고무재료의 개발을 목적으로 NBR에 oleamide와 아라미드를 첨가하여 함량에 따른 가황특성, 물리적 성질, 내열성, 내유성, 내마모성, 내균열성 및 내소 음성을 조사하였다. 가황특성과 Mooney 점도를 측정한 결과, 미가황고무의 가황특성은 oleamide의 양이 증가할수록 torque가 감소하였다. oleamide의 함량이 3 phr까지 증가함에 따라 경도 및 모듈러스 값은 조금씩 감소하였고 신장률은 감소하는 경향을 나타내었으며 인장강도는 거의 변화가 없었다. 내열성 시험(70시간, 120℃) 및 내유성 시험(70시간, 40℃)을 수행한 결과, 인장강도와 신장률이 모두 감소하였으며, TGA/DSC 분석 결과 첨가제에 따른 배합고무재료의 열적 특성은 변화가 없었다. 기본물성, 내마모성, 내소음성 및 내균열성을 종합한 결과, NBR 22700l 고무재료에서 내마모성과 내소음성에 대한 oleamide의 최적배합비는 3 phr였으며, 내균열성에 대한 아라미드의 최적배합비는 l phr로 나타났다. This study are conducted for the purpose of developing rubber material with noise and crack resistance. Cure characteristics, physical properties, thermal resistance, fuel resistance, abrasion resistance, crack resistance and noise resistance of NBR compounds with the various amounts of oleamide and aramid chip were investigated. From the measurements of cure characteristics and Mooney viscosities, cure characteristics of uncured rubber showed that a torque was decreased as the amount of oleamide increased. Hardness, modulus and elongation of rubber specimens tended to be reduced gradually, however, tensile strength remained unchanged as the amount of the oleamide increased. As a testing results of heat resistance for 70 hours at 120°C and oil resistance for 70 hours at 40°C, tensile strength and elongation were all reduced. From the TGA/DSC analysis, there was no such a change observed in thermal characteristics of rubber materials. As a result of testing basic physical properties, abrasion resistance, noise resistance and crack resistance, the optimum ratio of oleamide to NBR was found to be 3 phr, while that of aramid to NBR 227001 was 1 phr.
김현묵(Hyun Muk Kim),배성훈(Seong Hun Bae),박철현(Cheol Hyeon Park),전혁수(Hyeok Soo Jeon),김정수(Jeong Soo Kim) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12
본 연구에서는 사출관 내부의 이상 유동에 대한 수치해석을 수행하였다. 탄이 사출되지 않는 고정된 벽면에서 계산이 진행되었고, 증발이 완료된 물을 냉각제로 사용하였다. 주입구로 들어오는 고온의 공기와 냉각제간의 상호작용 및 유동장을 해석하기 위해 realizable k-ε 난류 모델과 VOF(Volume Of Fluid) 모델을 선정하여 냉각제 유량에 따른 수치 해석을 진행하였다. 해석결과, 사출관 상부 압력은 냉각제 유량에 따라 비선형적으로 증가하였다. 사출관 하부의 초기 온도는 냉각제량의 증가에 비례하여 감소하지만, 특정시간 이후 경향이 역전되면서 오히려 온도가 상승하였다. 또한, 혼합가스의 순환유동에 의해 초기의 온도값이 요동하는 경향을 확인하였다. Numerical simulations on the two-phase flow in an ejection canister were performed in this study. Calculation was done in a fixed wall situation where the missile does not move, and fully evaporated water was used as a coolant. To analyze the interaction among the hot gas, coolant, and mixture flow, realizable k-ε turbulence and VOF(Volume Of Fluid) model were chosen and parametric study was performed with the change of coolant flow rate. It could be found that the pressure on the canister top nonlinearly increased with the increase of coolant flow rate. The temperature on the canister bottom indicated a decrease being proportional to coolant flow rate in early times but after a specific time, the temperature increased with the tendency being reversed. In addition, the early part of temperature showed a fluctuating phenomenon because of the overall circulatory flow of mixture gas.
다상 유동모델과 동적 격자계를 활용한 가스-스팀 발사체계의 열유동과 탄의 운동성능 해석
김현묵(Hyun Muk Kim),배성훈(Seong Hun Bae),박철현(Cheol Hyeon Park),전혁수(Hyeok Soo Jeon),김정수(Jeong Soo Kim) 한국추진공학회 2017 한국추진공학회지 Vol.21 No.2
In this study, an analysis of the thermo-fluid dynamic and missile-motion performance was carried out through a numerical simulation inside the missile canister. Calculation was made in an analytical volume using dynamic grid and evaporated water was used as a coolant. To analyze the interaction among the hot gas, coolant, and mixture flow, Realizable k-ε turbulence and VOF (Volume Of Fluid) model were chosen and a parametric study was performed with the change of coolant flow rate. As a result of the analysis, pressure of the canister showed a large difference depending on the presence or absence of the coolant, and also showed a dependancy on the amount of coolant. Velocity and acceleration were dependent on the canister pressure.
1-(Benzotriazol-1-yl)alkyl Aryl Sulfone의 합성
홍영석,김현묵,이정근,박용태,김호식,Hong, Young Seuk,Kim, Hyun Muk,Lee, Jeong Geun,Park, Yong Tae,Kim, Ho Sik 대한화학회 1996 대한화학회지 Vol.40 No.9
1-(Benzotriazol-1-yl)-1-benzenesulfonylmethane 1a에 LDA 및 methyl iodide를 작용시켜 1-(Benzotriazol-1-yl)-1-benzenesulfonylmethane 2a와 2-(Benzotriazol-1-yl)-2-benzenesulfonylpropane 2b를 각각 얻었다. 같은 방법으로 1-(Benzotriazol-1-yl)-1-benzenesulfonylmethane 1b로부터 1-(Benzotriazol-1-yl)-1-benzenesulfonylpropane 3a와 3-(Benzotriazol-1-yl)-3-benzenesulfonylpentane 3b를 얻었다. 한편, 1, 1-di(benzotriazol-1-yl)-1-arylmethane 4를 butyl lithiym과 diphenyl disulfide로 처리하여 1, 1-di(benzotriazol-1-yl)-1-aryl-1-thiophenoxymethane 5를 합성하였다. 1, 1-di(benzotriazol-1-yl)methane 8을 butyl lithiym과 diphenyl disulfide로 처리하여 1, 1-di(benzotriazol-1-yl)-1-thiophenoxymethane 9a와 1, 1-di(benzotriazol-1-yl)-1, 1-dithiophenoxymethane 9b를 각각 얻었다. 화합물 9a를 m-CPBA로 산화시켜 1, 1-di(benzotriazol-1-yl)-1-benzenesulfoxymethane 10a와 1, 1-di(benzotriazol-1-yl)-1-benzenesulfonylmethane 10b를 얻었다. 한편, 화합물 3b를 170.deg.C 에서 열분해시켜 3-toluenesulfonyl-2-pentene 11ㅇ르 얻었으며, 150.deg.C의 강철봄베속에서 3b를 과량의 물로 가수분해 시켰더니 sulfone의 C-N 및 C-S 결합 모두가 절단된 diethyl ketone 13a가 생성됨을 확인하였다. (Benzotriazol-1-yl)arenesulfonylalkanes, 2a, 2b, 3a and 3b, were prepared by lithiation of 1-(benzotriazol-1-yl)arenesulfonylmethanes followed by reaction with alkyl iodides. Very bulky molecules such as 1,1-di(benzotriazol-1-yl)-1-aryl-1-thiophenoxymethanes 5, 1,1-di(benzotriazol-1-yl)-1-thiophenoxymethane 9a and 1,1-di(benzotriazol-1-yl)-1,1-dithiophenoxymethane 9b were synthesized. 1,1-Di(benzotriazol-1-yl)-1-benzenesulfoxymethane 10a and 1,1-di(benzotriazol-1-yl)-1-benzenesulfonylmethane 10b were also synthesized by the oxidation of compound 9a, while oxidation of sulfide group on compound 5 and 9b by m-CPBA were not successful. On the other hand, pyrolysis and hydrolysis of 3-(benzotriazol-1-yl)-3-toluenesulfonylpentane 3b gave 3-toluenesulfonyl-2-pentene 11 and diethyl ketone 13a, respectively, which means there are both C-N and C-S bond cleavages.