• Fire Science and Engineering
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• v.25 no.2
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• pp.126-131
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• 2011

This study is intended to understand mass loss rate and air entrainment rate of the whirl fire by height of fire source. Liquid fuels were methanol and n-Heptane which are used in many studies of whirl fire. Size of vessel was 100 mm ${\times}$ 100 mm ${\times}$ 50 mm and the vessel was made by stainless steel. When height of fire source changed from 0 cm to 30 cm, air entrainment rate showed the fastest in case of 0 cm. And in the same height of fire source, average and maximum air entrainment rate showed the fastest in 30 cm of anemometer. From the results of whirl fire for methanol and n-Heptane, mass loss rate and air entrainment rate of n-Heptane was found to faster 1.33 to 1.58 times and 4.38 to 5.44 times compared with methanol, respectively. Consequently, mass loss rate and air entrainment rate in whirl fire was able to identified decrease as height of fire source increases and the higher the heating value, increases the that's value.

• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.8-14
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• 2013

Hydrogen-natural gas blends(HCNG) engine is optimizing technology of performance and emission characteristics with use of hydrogen's fast flame speed and wide flammability limit. As lean-burn limit is extended, the improvement in thermal efficiency and harmful emissions can be achieved. However, the extension of lean-burn limit under a wide open throttle operation point could be realized with the increase in boosting capacity in a lean-burn engine with turbo-charging system. In the present study, the power output characteristics of HCNG engine with turbo-charger change is assessed and feasibility of the increase in boosting capacity is evaluated. The turbo-charger design with high efficiency at higher flow rate rather than higher boosting pressure makes efficient operation possible at relatively rich mixture condition.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.1
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• pp.17-26
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• 2005

Both numerical analysis and cold tests for the swirl coaxial type injector were performed to obtain the influence of spray angle, velocity ratio and liquid film thickness for pressure drop and recess. The basic experimental and numerical data obtained in this study can be applicable to the performance design of swirl coaxial type injector. Spray angle was not affected by the applied test pressure drop, but spray angle was affected by tangential velocity ratio and shape factors. Feasibility of numerical analysis for the liquid film thickness and spray angle was confirmed, and the change of liquid film thickness by tangential velocity ratio affected more seriously than pressure drop, and liquid film thickness was decreased with increasing tangential velocity ratio.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.53-59
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• 2015

Combustion characteristics for co-firing of biomass (Walnut Shell) as blending fuel in coal fired boiler have investigated using thermogravimetric analyser (TGA) and drop tube reactor (DTR). The results show that devolatilization and char combustion for WS occurs at lower temperature than those of existing coals and has lower activation energy value, which is resulting in higher reactivity. When the WS is blended with coal, TGA results show linear profiles depending on blending ratio for each fuel. However, DTR results exist the non-additive phenomena for blending of WS. As blending ratio of WS increase, the UBC decrease at BBR 5%, but the UBC rather increase from BBR 10% due to oxygen deficiency formed from rapid combustion of WS. This paper propose that fuel lean condition by oxygen rich lead to higher blending ratio of biomass by solving the oxygen deficiency condition.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.698-698
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• 2009

화력발전이 많은 비중을 차지하는 전력생산 산업은 온실가스($CO_2$)의 최대 배출 원으로 알려져 있으며 증가하는 전력 수요 뿐 만 아니라 다가오는 기후변화협약에 대응하기 위하여 $CO_2$ 회수 및 공정 개선에 관한 연구가 많이 수행되고 있다. 특히 현재 연구되고 있는 전력분야의 대표적인 $CO_2$ 회수기술은 연소 후 포집(Post-combustion capture), 순산소 연소(Oxy-fuel combustion), 연소전 탈탄소화(Pre-combustion) 3가지로 구분된다. 이중 연소전 탈탄소화 기술은 석탄가스화복합발전(IGCC) 기술과 연계하여 $CO_2$를 회수할 수 있는 방법으로 가스화 된 석탄가스에 Water-Gas Shift 반응과, $CO_2$ 분리로 얻어진 탈 탄소 연료를 통해서 전력을 생산한다. 이 기술의 핵심은 생성된 $CO_2/H_2$ 복합가스로부터 $CO_2$를 분리하는 공정으로 차세대 회수 기술로는 Membrance Reactor, SOFC, Oxygen Ion Transfer Membrane(OTM), 그리고 가스 하이드레이트가 있다. 이중 가스 하이드레이트는 $CO_2$의 회수 뿐 만 아니라 처리 기술에도 적용 가능하지만 우리나라에는 이에 관한 기술이 전무한 형편이다. 본 연구에서는 가스 하이드레이트 형성원리를 이용하여 정온 정압 조건에서 $CO_2/H_2$ 하이드레이트를 제조하였으며 특히, 하이드레이트 형성 촉진제인 THF(Tetrahydrofuran)를 첨가하여 THF 농도에 따른 상평형 및 속도론 실험을 수행 하였다. 이러한 연구는 연소전 탄소화 기술에서의 $CO_2$ 회수 분리에 대한 핵심 연구임과 동시에 탄소배출권 규제에 실질적인 기여를 할 수 있을 것으로 사료된다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.10
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• pp.60-65
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• 2003

An experimental study was performed to understand ignition characteristics of gas turbine combustor with rotating fuel injection system. Liquid fuel applied to the inner surface of rotating fuel nozzle which was driven by high speed electrical motor is flung away by centrifugal forces. The real scale combustor and test rig was manufactured and tested under atmospheric condition in KARl combustion test facility. From the test results, this combustor ignition characteristics are highly dependent upon fuel nozzle rotating speed. Futhermore, combustor exit gas temperature was rapidly changed by increasing or decreasing the fuel nozzle rotating speed.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.4
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• pp.40-49
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• 2016

This study aims to confirm the characteristics of low swirl combustion at our low swirl model combustor. To do it, it is experimentally conducted by evaluating the flame shape, stability region and emissions according to the swirl angle. The most significant feature of low swirl combustion is a occurrence of lifted flame. Such lifted flames happen to combine exquisitely propagating feature of premixed flame with diverging flow. This feature of lifted flame was confirmed through a velocity flow field and visualized the flame in this model combustor. The visualized flame was classified according to the thermal power and equivalence ratio. The variation study in swirl angles showed that the lean flammable limit could be extended only by swirl angles. Also, as the swirl angle increased, it was confirmed that the NOx and CO emissions were decreased due to the mixing enhancement and shorter resident time.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.10-15
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• 2020

This study is about the changes in mechanical and combustion properties after the production of the combustion catalysts FeOOH and Fe₂O₃ having the same manufacturing method and application to the solid propellant. In order to make the FeOOH and Fe₂O₃ having the same manufacturing method, FeOOH was calcined at 200, 300, 400, 500℃ for 2 h, and the XRD results were confirmed. In addition, after applying the prepared catalyst to a solid propellant, it exhibited change in mechanical and combustion properties. As result of XRD, FeOOH was confirmed to change the crystal phase from Geothtie to Hematite between 200 and 300℃. The stress of the propellant hardly changed as the calcination temperature of the combustion catalyst incredsed, but the elongation increased when catalyst was calcined. the maximum value at 300℃. The burning rate confirmed that FeOOH without calcination was about 3~5% faster than other catalysts.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.420-425
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• 2011

In general, the decomposition of $CaSO_4$ formed by sulfation reaction in the in-furnace desulfurization process using limestone has strong effect on the desulfurization reaction under the oxy-fuel combustion condition. In this study, the conversion rates were measured and reaction rates were calculated in order to investigate the effects of the experimental variables such as temperature and the concentrations of $CO_2$, $O_2$, $SO_2$, on the $CaSO_4$ decomposition reaction using DTF (Drop Tube Furnace) in the desulfurization reaction. The conversion rate and the reaction rate of $CaSO_4$ decomposition reaction were increased with reaction temperature. $CO_2$ concentration has little effect on $CaSO_4$ decomposition reaction in the presence of $O_2$. Under the same experimental conditions, the decomposition rate of $CaSO_4$ was enhanced with the decreasing the $O_2$ concentration, but vice versa with the increasing of $SO_2$ concentration.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.725-731
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• 2018

The effects of catalysts addition on the carbonization reaction of biomass have been studied in a thermogravimetric analyzer (TGA). The sample biomasses were Bamboo and Pine. The catalysts tested were K, Zn metal compounds. The carbonization reactions were tested in the nonisothermal condition from the room temperature to $850^{\circ}C$ at a heating rate $1{\sim}10^{\circ}C/min$ on the flowing of $N_2$ purge gases. Also, the effects of catalyst on the torrefaction were tested in the temperature condition of 220, 250, $280^{\circ}C$ at 30 min. Combustion characteristic for the torrefied catalyst biomass were studied in the nonisothermal conditions of $200{\sim}850^{\circ}C$. As the results, the initial decomposition temperatures of the volatile matters ($T_i$) and the temperature of maximum reaction rate ($T_{max}$) were decreased with increasing the catalyst amounts in the sample biomass. The char amounts remained after carbonization at $400^{\circ}C$ increased with the catalyst amounts. Therefore catalysts addition can be decreased the energy for carbonization process and improved the heating value of product char. The catalysts reduced the optimum torrefaction conditions from $250^{\circ}C$ to $220^{\circ}C$. The torrefied catalyst biomass have lower activated energy from 46.5~58.7 kJ/mol to 25.1~27.0 kJ/mol in the nonisothermal combustion reaction.