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경사 정체점 유동이 적용된 미세 홀 레이저 가공 공정의 흄 오염입자 산포특성 연구
김경진,박중윤,Kim, Kyoungjin,Park, Joong-Youn 한국반도체디스플레이기술학회 2021 반도체디스플레이기술학회지 Vol.20 No.3
This numerical study focuses on the analysis of fume particle dispersion characteristics over the surface of target workpiece in laser micro-hole machining process. The effects of oblique stagnation flow over fume generating machining point are examined by carrying out a series of three-dimensional random particle simulations along with probabilistic particle generation model and particle drag correlation of low Reynolds number. Present computational model of fume particle dispersion is found to be capable of assessing and quantifying the fume particle contamination in precision hole machining which may influenced by different types of air flow patterns and their flow intensity. The particle size dependence on dispersion distance of fume particles from laser machining point is significant and the effects of increasing flow oblique angle are shown quite differently when slot blowing or slot suction flows are applied in micro-hole machining.
김경진(Kyoungjin Kim),박중윤(Joong-Youn Park) 한국추진공학회 2015 한국추진공학회지 Vol.19 No.6
This paper introduces a zero-dimensional modeling on the plasma generation in electrothermal gun operation. The plasma generator consists of alumina bore and aluminum electrodes which is electrically powered by outer pulse forming network and, traditionally, its numerical simulations have employed time-dependent one-dimensional governing equations. However, by assuming isothermal approximation along the bore and choked bore exit condition, present analysis simplifies the mass and energy equations into zero-dimensional approximation of plasma conditions coupled with mass ablation model and plasma property evaluation. The numerical results show good agreement with the corresponding one-dimensional computations and thus verify the present modeling approach.
보론/티타늄 나노박막다층 내 이종금속간 화학반응 전파특성 해석연구
김경진(Kyoungjin Kim),박중윤(Joong-Youn Park) 한국추진공학회 2017 한국추진공학회지 Vol.21 No.3
The analytical modeling has been established on the self-propagation of intermetallic reaction in the spanwise direction of highly reactive boron and titanium nanoscale multilayers. Assuming that the reaction obeys Arrhenius kinetics, two-dimensional computations are carried out for heat and atomic species diffusion with exothermic reaction model in order to simulate the self-propagation of intermetallic reaction. The effects of bimetallic layer thickness and thickness ratio on the reaction propagation speed are tested and discussed in addition to the assessment of pre-mixing zone effects.
박중윤 國立金烏工科大學校附設生産技術硏究所 1991 産業技術開發硏究 Vol.7 No.-
This paper presents and analysis of the vibration system with a dynamic absorber. The purpose of this paper is to suggest one of directives to design passive and active dynamic absorbers. If the exciting frequency of the exciting force is harmonic(or constrant), the passive absorber is effective. In this case, optimal tuned absorber suppresses the vibration of the main system. On the contrary, the mistuned absorber promotes the vibration. Thus, vibration amplitude for design variables of the absorber is investigated. In random or irregular exciting force, the active absorber is more effective. In this case, the control law is used as optimal regulator theory. Design variables of weighting matrix and feedback gain vector are considered, and an optimal design chart can be obtained from this design variables. It is demonstrated that this method is effective for the design of an active vibration absorber.
박중윤 金烏工科大學校 1990 論文集 Vol.11 No.-
The multiple regenerative chatter vibration due to the deflection of tool occurring in orthogonal cutting is investigated. Tool deflection is a bad chatter condition and causes severe chatter. General chatter generates the constant chatter amplitude, but severe chatter due to small tool deflection has varying chatter amplitude and chatter frequency. It is shown that the severe chatter with large tool deflection, the larger chatter amplitude, but the chatter amplitude and chatter frequency are kept constant.
朴重潤 金烏工科大學校 1987 論文集 Vol.8 No.-
A new method for analysis of chatter vibration is presented. It is shown that vibrating energy of the multiple regenerative chatter is maximized when chatter is fully developed. It is assumed that chatter frequency is constant, and motion has finite limit amplitude. Thus, linear analysis is possible by taking the Fourier Series expansion for nonlinear cutting force. In this paper, chatter frequency is varied to maximize the vibrating energy, and chatter amplitude in this condition is also computed. The results of this method is compared with that of direct numerical integration method. The results obtained by each method are good agreements when chatter amplitude has finite limit cycle. This method is useful for one degree of freedom system because of assumption.