난류확산 화염간의 상호작용 특성

전철균,김호영 대한기계학회 1990 대한기계학회 춘추학술대회 Vol.- No.-

비균일 액적 분포가 액적군의 비정상 집단연소에 미치는 영향 ( The Effects of Non-uniform Droplets Distribution on Transient Group Combustion of Fuel Droplets Cloud )

전철균,김호영 대한기계학회 1986 대한기계학회 춘추학술대회 Vol.- No.-

로내 부양 연소모델에 관한 연구

전철균 국립7개대학공동논문집간행위원회 2005 공업기술연구 Vol.5 No.-

A combustion model for the PRF(processed refuse fuel) suspended in furnace is developed. It is assumed that each piece of PRF has a shape of disk and burns independently. Each piece of PRF contains moisture, volatile, fixed carbon and ash. Arrhenius equation is used for analyzing thermal decomposition and fixed-carbon combustion. A computational analysis based on developed model is conducted to predict the characteristics of suspended PRF. The variation of diameter, thickness and gas temperature are used as a parameter. It is found that the velocity of suspension of PRF can be predicted with this model. The combustion rate, burning time and residence time can be predicted also. It is predicted that the suspension condition is more sensitive in vertical disk than horizontal disk.

방 안에서의 가스연료 누출에 관한 연구

전철균 木浦大學校 工業技術硏究所 1996 工業技術硏究誌 Vol.6 No.-

Explosion caused by the leak of gaseous fuel is a serious problem today. To avoid the accident, safe depletion of the leaked fuel is very important. Depletion of leaked fuel by ventilation through windows of room was studied numerically. It is found that the role of recirculation flow between main stream and fuel layer is very important. This flow moves from the location near intake window to that of exhaust window repeatedly and enhances the mass transfer of fuel to vetilation stream. Height of intake window causes fast exhaust of fuel is low. Initially, volume of ignitable mixture is large for the case of high windows, but this volume becomes large for the case of low intake window at the later time.

상호작용하의 층류 확산 화염에서 NO의 생성

전철균 대한기계학회 1993 대한기계학회논문집 Vol.17 No.1

본 연구에서는 화염간 상호작용이 연소생성물 형성에 미치는 영향을 규명하기 위한 작업의 일환으로 대표적 연소 생성 공해 물질의 하나인 NO를 택하여 상호작용하 의 층류 확산화염에서 NO의 생성이 어떻게 이루어지는가를 검토 하고자 한다. 이를 위하여 기본적 다화염계인 2-화염계를 모사하는 수학적 모델을 수립하고 수치 계산을 통한 이론적 방법을 위주로하여 2개의 층류 확산 화염이 나타내는 상호작용 특성과 화 염간 상호작용이 NO형성에 미치는 영향을 규명하고자 한다. In order to find the effect of flame interaction on NO production, dual laminar diffusion flames issuing from two rectangular nozzles were investigated theoretically. Chemical equilibrium model and Zeldovich mechanism were used in numerical model. The effect of four major parameters on NO production were inspected. These parameters are nozzle spacing, Raynolds number, aspect ratio of nozle cross section and velocity of secondary flow. It is found that interaction of flames enhances production of n. It is also found that multiflames with large spacing, small aspect ratio and strong secondary flow product less n.

자연대류가 존재하는 함수장방형 용기내의 고체/액체 상변화 현상에 관한 실험적 연구

全哲均,姜在一 木浦大學校 工業技術硏究所 1994 工業技術硏究誌 Vol.4 No.-

An experimental study on the phenomena of solidification of water in a cavity cooded from its top surface and heated from its lower surface is reported. Interface of solid and liquid regions, volume of pour out, inverse of density, the effects of initial temperature of water and the hot wall temperature during the solidification are investigated. The rate of solidification is less effected by the intial temperature of water in a cavity than those of the hot wall temperature. When the hot wall temperature is near 4°C the shape of interface is nearly pararell to the surface of heat transfer, but between 7°C and 8°C the interfaces are different from the case of 5°C. The volume of pour out is larger at low initial water and hot wall temperature than at hight. With increase in the Stefan number, the rate of solidification became weak and convection is more accelerated than conduction. The characteristics of the flow and temperature fields are also carefully examined by checking the temperature variation in a cavity.

병류형 로타리 킬른의 열적 특성에 관한 연구

박종석,전철균 한국연소학회 2007 한국연소학회지 Vol.12 No.3

A theoretical model was developed for parallel-flow rotary kiln and computational study was conducted to find the thermal characteristics. One dimensional model with the variations of heating distribution, length of heating zone, excess air ratio and revolution was considered. The comparison of parallel-flow rotary kiln with that of counter-flow was conducted. It is found that the variation of temperature of solid is not great for the zone that is following flame-heating zone. This zone is good to take the special treatment because thermal deviation is small and contacting time is enough for another treatment. Increase of excess air ratio have the effect of decreasing solid temperature. But this effect of decreasing solid temperature goes small for the great excess air ratio. The heating is efficient for the flame which has the maximum heating at the central region of the full length.

확산선호도가 비정상 집단연소 특성에 미치는 영향

김호영,전철균 고려대학교 공학기술연구소 1989 고려대학교 생산기술연구소 생기연논문집 Vol.25 No.1

In order to predict the effect of preferential diffusion (thermal diffusion / mass diffusion) on the characteristics of non-steady group combustion and flame structure, development of theoretical model and numerical analysis are carried out for the spherical liquid fuel droplets cloud. Lewis number is adopted as a mayor parameter to predict the effect of preferential diffusion, and predictions of flame structure and combustion characteristics are achieved for various Lewis number from numerical solutions. It was found that the external flame sheet moves to outward from the center of cloud and the fuel concentration at the center of cloud increases as Lewis number increases. As Lewis number increases, period of external and internal getup combustion increases and period of single droplet combustion decreases even overall combustion periods are same.

비균일 액적분포가 액적군의 집단연소 특성에 미치는 영향

김호영,전철균 대한기계학회 1987 대한기계학회논문집 Vol.11 No.3

본 연구에서는 액적들의 분포상태가 집단연소의 특성에 미치는 영향을 규명하 기 위하여 김의 비정상 집단연소모델에 비균일 액적크기분포와 수밀도분포를 고려한 비균일분포 집단연소모델을 구성하여 이론적으로 해석하였다. In order to predict the effects of droplets distributions such as number density and droplets size on group combustion characteristics and flame structure for liquid fuel sprays, modifications of group combustions model were made by changing the droplets distributions from uniform to non-uniform. Various droplets distribution models were adopted in this analysis to examine the effect of number density distribution on combustion characteristics and the difference between uniform and non-uniform droplets size distributions for a spherical droplets cloud. As results of present study, hollow droplets could with outer concentrating distribution has shorter total combustion time compare with the case of solid droplets cloud with inner concentrating distribution. Uniform droplets size distribution model predicts the shorter total combustion time compare with non-uniform droplets size distribution model, and the uniform droplets size distribution model may be used to predict the total combustion time for the droplets cloud containing larger initial size of droplets.

기체확산 화염간의 상호작용

김호영,전철균 대한기계학회 1991 대한기계학회논문집 Vol.15 No.1

본 연구에서는 화염간 상호 작용을 해석함으로써 정의 적용에 있어서의 적절 성과 유용성을 검토 하고 화염간 상호 작용 특성을 밝히기 위하여, 해석의 대상은 화 염간의 상호작용을 명확히 관찰할 수 있는 두 개의 평행한 사각 덕트형 노즐로부터 분 출되는 기체연료에 의해 형성 되는 두 개의 동등한 3차원 제트 난류 확산화염을 택한 다. 2-화염계는 상호작용 화염군의 기본 단위이며, 현재까지 원형제트 화염에 비하 여 3차원제트 화염에 대한 연구는 많지 않은 실정이다. 연구의 방법으로는 이론적 모델링과 수치해석을 통한 모의 실험에 중점을 두고 부분적인 실험으로 타당성을 점검 한다.이는 기존의 연구들이 대부분 실험적인 것들이거나 간단한 해석적 모델을 사 용한 것들이어서 상호 작용하의 화염 특성을 예측할 수 있는 수치 해석적 모델의 개발 이 필요하며, 또한 기존의 연구들이 온도나 성분만을 측정함으로서 유동장에서의 운동 량 전달의 상호작용 특성이 자세히 연구되지 못했으므로, 이를 위해서는 난점이 있는 속도 측정의 실험적 방법보다 수치해석적 접근법이 필요하기 때문이다. 이상과 같이 본연구는 상술한 정의를 적용해 보고 이에따라 화염간 상호작용의 특성을 파악하며 이 를 예측할 수 있는 이론적 모델을 개발하는 것을 목적으로 한다. New definition for the interaction of flames is introduced and interacting turbulent diffusion flames issuing from two rectangular nozzles are investigated on the basis of the definition. Theoretical study through numerical model is carried out and experiment for validation is conducted. The characteristics of interaction due to the variation of major parameters such as nozzle spacing, Reynolds number and nozzle aspect ratio are studied. Results show that strong interaction occurs for small nozzle spacing, small Reynolds number and large aspect ratio. In order of their magnitude, the intensity of interactions on the individual transport mechanism is momentum, heat and mass. It is also found that interaction makes flames longer, tilted and finally merged. Increase of velocities and temperature, decrease of oxygen concentration and depression of turbulence are occurred in the region between flames.