• 대한기계학회논문집
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• 제17권12호
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• pp.3187-3195
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• 1993

Combustion of liquid-fuelled combustion in a high-temperature vitiated-air stream was studied. The mathematical formulation comprise the application of Eulerian conservation equation to the gas phase and Lagrangian equation of droplet motion. The latter is coupled with a droplet-tracking technique (PSI-CELL Model) which regard the droplet phase as a source of mass, momentum, and energy to the gaseous phase. Reaction rate is determined by taking into account the Arrhenius reaction rate based on a single-step reaction mechanism. The calculated profiles show somewhat uncertainess at the upstream, but bases data for designing the combustor followed by 2-phase flow were obtained.

• 공학논문집
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• 제3권1호
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• pp.223-233
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• 1998

고상반응식을 이용한 석회와 석영과의 수열반응속도 및 반응메카니즘에 관하여 연구하였다. 출발물질로 석영과 수산화칼슘 CaO/$SiO_2$몰비 0.8-1.0로 혼합하고 $180-200^{\circ}C$, 0.5-8시간동안 포화증기압하에서 오토클레이브로 수열반응을 행하였다. 수열반응속도는 총 석회의 양과 총 석영의 양에 대한 미반응 석회의 양과 미반응 석영의 양의 비로 구하였다. 반응속도는 Jander의 식 $[1-(1-\alpha)^{1/3}]^N=Kt$를 이용하여 얻은 결과, 석회의 반응속도는 N=1로서 주로 용해속도에 의해 지배되고 석영의 반응속도는 $N\risingdotseq2$로서 확산에 의해 주로 지배된다. 규산칼슘수화물계의 수열반응속도는 반응물 입자주위에 형성된 생성물층을 통한 물질전달에 의해 율속되는 것으로 추정되고 전체 수열반응의 속도식은 대략 $N=1-2$로서 경계층으로부터 확산에 의해 율속과정으로 전환된다.

• 환경위생공학
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• 제17권1호
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• pp.69-74
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• 2002

This study explored for treatment processes by investigating the treatment efficiency and reaction mechanism through oxidation reaction using UV and $O_3$ as oxidant in compensate the wastewater containing nitrobenzene that is non biodegradable organic. Also by modeling these reactions, we try to step explanation of optimum reaction rate and reaction mechanism as the development of the computer program predictable the reaction rate by modeling the reaction. By using this model, after kinetic constant for each reaction from an experimental data is made an optimization and for hardly contribute to reaction rate in reaction kinetic equation is made an ignorance and suppose the simplified reaction mechanism, examined the propriety of computer simulation model and simplified reaction mechanism by comparing and inspecting the reaction kinetic constant and masstransfer coefficient. An investigation results for destructional treatment of nitrobenzene in the wastewater as non-biddegradable organic using UV, $O_3{\;}O_2{\;}H_2O_2-UV$ as oxidant.

• 설비공학논문집
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• 제13권7호
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• pp.637-646
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• 2001

VOC(Volatile Organic Compound) removal characteristics in continuous flow reactors have been numerically investigated. The photocatalytic reaction have been simulated with the binding constant and the reaction rate constant obtained from experimental data for the constant-volume batch reactor, and then VOC abatement in continuous flow reactors with the same conditions as those of batch reactor has been analyzed. The standard 4\kappa-\varepsilon$ model and mass conservation equation have been employed for numerical calculation, and heterogeneous reaction rate has been used in terms of the boundary condition of the conservation equation. in the case of the continuous flow reactor, reaction characteristics have been estimated with various inlet velocities and with different number of baffles. The result shows that the concentration distribution and flow patterns are strongly affected by the inlet velocity, and that with the increased inlet velocity, VOC removal rate is increased, while removal efficiency is decreased. This result may be useful in the design of reactors with improved VOC removal efficiency.

• 공업화학
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• 제5권4호
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• pp.731-736
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• 1994

DGEBA/MDA/MN계와 이 계에 촉매로서 hydroquinone(HQ)를 첨가한 계의 경화반응 속도론을 Fractional life법 및 Kissinger equation에 의해 연구함으로써 HQ가 경화반응 속도에 미치는 영향을 연구하였다. 경화반응 온도가 증가함에 따라 반응속도는 증가하였고, 반응차수는 약간의 변화가 있을 뿐 경화온도에 따른 경향성은 없었다. 촉매로 HQ를 첨가한 계가 첨가하지 않은 계보다 반응속도는 크게 증가하였고, 활성화 에너지는 13% 감소하였다. 이는 HQ의 히드록시기가 에폭사이드기, 아민기와 반응하여 전이상태를 형성함으로써 에폭사이드 고리를 쉽고 빠르게 개환시켜 주기 때문이다.

• 산업기술연구
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• 제17권
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• pp.241-247
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• 1997

A numerical model has been proposed for a diffusion flame reactor to manufacture ultrafine $TiO_2$ powders. The model equations such as mass balance equation, the 0th, 1st, and 2nd moment equations of aerosols were considered. The phenomena such as $TiCl_4$ reaction rate, $TiO_2$ nucleation rate and the coagulation of $TiO_2$ powders were included in the aerosol dynamic equation. It is found that the $TiO_2$ particle concentration becomes higher, as the inlet $TiCl_4$ concentration and the total gas flow rate increase, and also as the flame temperature decreases. The $TiO_2$ particle size increases, as the flame temperature and the inlet $TiCl_4$ concentration increase and the total gas flow rate decreases.

• Korea-Australia Rheology Journal
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• 제14권2호
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• pp.63-70
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• 2002

Chemical mechanical planarization (CMP) is the polishing process enabled by both chemical and mechanical actions. CMP is used in the fabrication process of the integrated circuits to achieve adequate planarity necessary for stringent photolithography depth of focus requirements. And recently copper is preferred in the metallization process because of its low resistivity. We have studied the effects of chemical reaction on the polishing rate and surface planarity in copper CMP by means of numerical simulation solving Navier-Stokes equation and copper diffusion equation. We have performed pore-scale simulation and integrated the results over all the pores underneath the wafer surface to calculate the macroscopic material removal rate. The mechanical abrasion effect was not included in our study and we concentrated our focus on the transport phenomena occurring in a single pore. We have observed the effects of several parameters such as concentration of chemical additives, relative velocity of the wafer, slurry film thickness or ash)tract ratio of the pore on the copper removal rate and the surface planarity. We observed that when the chemical reaction was rate-limiting step, the results of simulation matched well with the experimental data.

• 한국환경과학회지
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• 제30권5호
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• pp.399-406
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• 2021

The dissolution of ionized gas in dielectric barrier plasma, similar to the principle of ozone generation, is a major performance-affecting factor. In this study, the plasma gas dissolving performance of a gas mixing-circulation plasma process was evaluated using an experimental design methodology. The plasma reaction is a function of four parameters [electric current (X₁), gas flow rate (X₂), liquid flow rate (X₃) and reaction time (X₄)] modeled by the Box-Behnken design. RNO (N, N-Dimethyl-4-nitrosoaniline), an indictor of OH radical formation, was evaluated using a quadratic response surface model. The model prediction equation derived for RNO degradation was shown as a second-order polynomial. By pooling the terms with poor explanatory power as error terms and performing ANOVA, results showed high significance, with an adjusted R² value of 0.9386; this indicate that the model adequately satisfies the polynomial fit. For the RNO degradation, the measured value and the predicted values by the model equation agreed relatively well. The optimum current, gas flow rate, liquid flow rate and reaction time were obtained for the highest desirability for RNO degradation at 0.21 A, 2.65 L/min, 0.75 L/min and 6.5 min, respectively.

• 공업화학
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• 제26권2호
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• pp.184-192
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• 2015

석유 코크스, 바이오매스, 혼합연료들의 이산화탄소 가스화 반응성을 측정하고 비교하기 위해서 TGA (Thermogravimetric analyzer)를 이용하여 $1,100{\sim}1,400^{\circ}C$의 char-$CO_2$ 가스화 반응을 조사하였다. 기-고체반응속도 모델들에 적용하여 $1,100{\sim}1,400^{\circ}C$의 온도 영역에서의 반응 속도 상수를 구하였다. 또한 반응 속도 상수와 온도와의 관계를 Arrhenius 식에 적용하여 각 모델에서의 활성화에너지(Ea) 및 빈도 인자($K_0$)를 구하고 이를 실험값과 비교하여 석유 코크스, 바이오매스, 혼합 연료들의 이산화탄소 가스화 반응을 잘 모사하는 반응 속도식을 제시하였다. 반응온도가 증가할수록 이산화탄소 가스화에 소요되는 반응시간은 감축되었다. 또한 바이오매스와의 혼합이 증가할수록 활성화 에너지의 감소를 보여 바이오매스의 혼합이 석유 코크스의 이산화탄소 가스화 반응에 시너지 효과를 가져옴을 확인하였다.

• Journal of Mechanical Science and Technology
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• 제15권4호
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• pp.473-481
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• 2001

By depicting the transfer of heat and combustion reaction to take place within thin gas layers close to the propellant surface burning in a steady-state fashion, a mathematical equation has been deduced to describe the burning rate of solid propellant as a function of initial grain temperature and chamber pressure. It has been also assumed that chemical reaction could take place in premixing-diffusing zone but were carried out mainly in the reaction-flame zone. All these phenomena taken place in each zone of combustion have been assumed to be steady-state. In the present investigation, the equation, γ=$\kappa$$.$(1/R(T(sub)i+C))(sup)n$.$exp(-E(sub)a/R(T(sub)i+C))(P/z) is being presented and it is compared with experimental data. The proposed model has been tested and evaluated vis-a-vis strand burner data for three different propellants based on CTPB, and it has been found that the deviation of the computed burning rates from the measured rates ranged up to 2%.