• 설비공학논문집
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• 제8권4호
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• pp.463-472
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• 1996

Experiments were carried out to study the operation characteristics of a regenerator with a thermo-syphon pump and a surface-flame burner for a lithium bromide (LiBr)-water absorption heat pump. A cylindrical-shape metal-fiber burner and commercial grade propane were used. The emission of carbon monoxide and nitric oxide was measured by a combustion gas analyzer. Ther regeneration rate of water vapor as a refrigerant was measured. It could be as a reference value showing the performance of the regenerator. The circulation rate of the LiBr-water solution was also measured from both the tanks for the weak-and the strong-solution. Using a refractometer, the LiBr concetration in the solution was calculated from the measured refractory index of the solution. Temperature of the solution and the condensed water was recorded at several points in the experimental apparatus with thermocouples, using a personal computer. This data collecting system for measuring temperature was calibrated with a set of standard thermometers. The generating rate of water vapor as refrigerant increased linearly with heat supplied. It was about 4.0g/s with the heat supplied at a rate of 16,500kcal/h. The circulation rate of LiBr solution also increases with the heat supplied. The difference in LiBr concentrations between the weak and the strong solution was in the range of 1 to 5% when the concentration of the strong solution was about 60%. It was dependent upon both the heat supplied and the circulation rate of the solution. The initial concentration and the level of the LiBr solution in the regenerator were measured and recorded before experiments. The effect of them on the generating rate of water vapor and the circulation rate of the solution was also studied. The generating rate of water vapor was not strongly dependent upon both the level of the LiBr solution and the initial LiBr concentration. However, the concentration difference of the solution increases with the initial level of the LiBr solution.

• 대한기계학회논문집B
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• 제20권10호
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• pp.3243-3250
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• 1996

Emission characteristics of nitric oxides and carbon monoxide from a porous media combustor has been experiment studied. The relationship between the change of flame shape and emission has also been examined. As the equivalence ratio decreases, the flame shape on the ceramic matrix plate changes from a diffusion flame, R(radiant)-type flame, to B(Blue)-type flame. With large fuel flow rate, R-type flame turns to be two dimensional R-II type flame around the equivalence of 0.7. Carbon monoxide emission increases very rapid with decreasing equivalence ratio. It changes a lot from some 10 ppm to 100-10,000 ppm with the change of flame type from R-I to R-II type. Nitric oxide emission from the premixed burner is less than 25 ppm over all range of fuel flow rate, which is less than 20% of NOx emission from conventional gas burners.

• 대한기계학회논문집
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• 제19권3호
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• pp.858-867
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• 1995

Characteristics of premixed flames in counter-flow system are numerically studied using a detailed chemical reaction mechanism including gas phase radiation. Without radiation effect accounted, low CO and high NO$_{x}$ emission indices are observed, when strain rate decreases, due to increased residence time and higher flame temperature. Higher NO$_{2}$ production has been also observed when two premixed flames are interacting or cold air stream is mixed with burned gas. The rate of NO$_{x}$ production and destruction is dependent upon the diffusional strength of H and OH radicals, the existence of NO and the concentration of HO$_{2}$. For radiating flames, the peak temperature and NO$_{x}$ production rate decreases as the strain rate decreases. At high strain rate, it is found that the effect of radiation on flame is little due to its negligible radiating volume. It is also found that NO$_{x}$ production from the interacting premixed flame is reduced due to reduced temperature resulting from radiation heat loss. It is concluded that the radiation from gas has significant effect of flame structure and on emission characteristics.ristics.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.199-203
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• 2002

In this paper, the effects of water contents on combustion characteristics of paper sludge and capacity of fluidized bed combustor(FBC) were investigated using 0.26m diameter, 1.75m height pilot-plant scale combustor. Combustion tests of paper sludge containing water contents between 40wt% and 50wt% were performed. The temperature and emission variation, the pressure inside combustor were measured to monitor the fluidization quality. The experimental results showed that 30kg/hr feeding rate of sludge containing water up to 45wt% was preferable for this system. Sludge loading rate, heat release rate were calculated from experimental data as major parameters showing FBC capacity. Comparsion with sludge loading rate from other source was also performed

• 한국분무공학회지
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• 제22권4호
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• pp.197-202
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• 2017

The objective of this study is to investigate the effects of low-temperature combustion (LTC) on the correlations of combustion characteristics and reduction of exhaust emissions in a small DI diesel engine with biodiesel fuel. In order to analyze the combustion, exhaust emission characteristics and distribution of nano size particles for biodiesel were investigated. In addition, to evaluate the effect of LTC on the combustion and emission characteristics, 30 and 50% of cooled-EGR rates were investigated. From these results, it revealed that the influence of LTC on the combustion characteristics showed that the ignition delay significantly increased and reduces peak heat release rate of premixed combustion by lowering reaction rate. With 50% EGR and advanced injection timing, soot and $NO_x$ emissions were simultaneously reduced.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.35-36
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• 2009

Development trend and current status were surveyed for pre-heat-treated high strength cold heading quality (CHQ) wire and it's forming technology. Spheroidizing, quenching, and tempering heat treatments are eliminated by adapting the pre-treated wire, which could reduce energy consumption rate and green house gas emission rate during produce parts requiring high strength. There are some challenging problems to expand application area such as enhancing forming tool life, and preventing delayed failure. Domestic research movement concerning the development and application of the new high strength wire was introduced.

• 설비공학논문집
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• 제18권6호
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• pp.468-476
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• 2006

The paper deals with the numerical analysis of contaminants emission from the material affected by temperature variation in floor heating system. Considering mass transfer and heat transfer theories, a computer program for the analysis of VOCs emission was made. To demonstrate the accuracy of the numerical solution, the prediction results and the measured data were compared. Using this program, emission rates of the materials in the bakeout space and the no bake-out space were compared to estimate the variation of emission rate.

• 한국태양에너지학회 논문집
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• 제31권1호
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• pp.100-106
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• 2011

This study proposes a $CO_2$ emission reduction method through correlation analysis of a sample building. First, energy saving factors of heating, cooling, lighting were determined for the correlation analysis and $CO_2$ emission contribution rate of the design parameters have been analyzed. Then optimal combination of each design parameter has been drawn. Heat transfer coefficient of walls and windows, air permeability, windows area ratio, and shading devices were selected as applicable energy saving factors of the sample building. Also computer simulation was conducted using experimental design by Orthogonal Arrays of the statistical method. And the contribution rate was estimated by Analysis of Variance-ANOVA. As a result, the $CO_2$ emission in heating was reduced to 51.9%; in cooling to 16.8%; and in lighting to 2% compared to the existing building. The majority of the reduction was presented by heating energy.

• Journal of Mechanical Science and Technology
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• 제17권8호
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• pp.1185-1195
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• 2003

Heat losses from the receivers of a dish-type solar energy collecting system at the Korea Institute of Energy Research (KIER) are numerically investigated. It is assumed that a number of flat square mirrors are arranged on the parabolic dish structure to serve as a reflector. Two different types of receivers, which have conical and dome shapes, are considered for the system, and several modes of heat losses from the receivers are thoroughly studied. Using the Stine and McDonald model convective heat loss from a receiver is estimated. The Net Radiation Method is used to calculate the radiation heat transfer rate by emission from the inside surface of the cavity receiver to the environment. The Monte-Carlo Method is used to predict the radiation heat transfer rate from the reflector to the receiver. Tracing the photons generated, the reflection loss from the receivers can be estimated. The radiative heat flux distribution produced by a multifaceted parabolic concentrator on the focal plane is estimated using the cone optics method. Also, the solar radiation spillage around the aperture is calculated. Based on the results of the analysis, the performances of two different receivers with multifaceted parabolic solar energy collectors are evaluated.

• 한국산학기술학회논문지
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• 제10권7호
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• pp.1465-1472
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• 2009

완전혼합 반응기에서 외부로의 열손실이 $CH_4/air$예혼합화염의 NOx 생성특성에 미치는 영향을 수치해석으로 검토하였다. 주요 결과로서, 단열조건에서 NOx는 체류시간에 따라 급격히 증가하는 반면에, 열손실이 고려될 때 열전 달 상수와 체류시간의 증가에 따라 NOx 저감현상이 뚜렷하게 발생하였다. 민감도 해석을 통해 열손실율이 증가함에 따라 Thermal NO 기구와 Re-burning NO 기구는 NOx 저감에 크게 기여하는 반면, Prompt NO 기구와 $N_2O$-경유 NO 기구는 오히려 NOx 증가에 기여함을 확인하였다. NOx 생성기구는 열전달 상수 및 체류시간의 변화에 따라 매우 복합한 특성을 갖지만, NOx 농도는 독립된 Thermal NO 기구에 의해 표현될 수 있었다. 이를 통해 실용 $CH_4/air$예혼합 연소기에서 NOx 농도를 예측할 수 있는 열손실율과 체류시간을 조합한 새로운 NOx 상관식이 도출되었다.