• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.737-744
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• 2011

The success of continuous aluminum powder combustion with steam plasma is different from hydrocarbon ignition source. Ignition characteristics of aluminum powder with high temperature thermal plasma is studied with oxidizer-free environment. Experiment with argon plasma has same temperature conditions at 4500 K and particle feeding condition for previous combustion test with steam plasma and swirl combustor. The temperature of the plasma was measured using Optical Emission Spectroscopy method. Ignition characteristics were analyzed by SEM image and EDS. Aluminum powder with plasma has rapid evaporation mechanism contrast to hydrocarbon ignition source. It enhances to aluminum powder effective ignition characteristics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.258-262
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• 2011

The laminar burning velocity in premixed Oxy-CH4 flames was studied in a lab-scale Bunsen burner. $CH^*$ chemiluminescence method and Schliren photography were used. Experimental results were compared with numerical prediction which was calculated with a CHEMKIN 3.7 package with a PREMIX code. Global equivalence ratio of oxy-CH4 mixture was varied from 0.5 to 2.0 in a laminar flow region. The laminar burning velocity was measured as 3.1 m/s for Schlieren photograph and 2.9 m/s for $CH^*$ chemiluminescence technique (angle method).

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.551-557
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• 2001

La$_{0.7}$Ca$_{0.3}$MnO$_3$분말을 용액연소법으로 제조하였으며 분말 특성과 CMR에 응용하기 위해 박막의 전기적, 자기적 특성을 조사하였다. 조성과 구조 특성을 XRD와 SEM으로부터 조사하였으며 분말의 하소온도를 TG 분석으로부터 결정하였다. 또한 소결성은 dilatometer에 의해 조사되었으며 분말 특성은 BET에 의해 조사되었다. 소결성이 우수한 분말을 이용하여 스퍼터 타겟으로 제조하였으며 SiO$_2$/Si 기판 위에 스퍼터링한 후, 온도에 따른 four point probe 측정으로 막의 MR비를 측정하였다. VSM (Vibrating Sample Magnetometer)를 이용하여 증착된 막의 온도에 따른 자화율(Magnetization:M)을 측정하였다. 분말 특성으로는 평균입자 크기가 sub-micron 이하로 초미세하고 49.44$m^2$/g의 비표면적 값을 얻을 수 있었으며 고순도의 perovskite 구조를 갖는 La$_{0.7}$Ca$_{0.3}$MnO$_3$분말을 쉽게 얻을 수 있었다. 온도에 따른 저항값의 변화로부터 96K에서 최고의 MR값을 얻을 수 있었으며, 240K에서 강자성체로 전이되었다.로 전이되었다.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.44-49
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• 2011

A study of the fatigue life of copper alloy which was used in inner jacket of regenerative cooling chamber of liquid rocket engine has been performed. Generally used life prediction methods -original universal slopes method, modified universal slopes method, Mitchell's method, B$\"{a}$umel and Seeger's method, and Ong's method- have been used for predicting the fatigue data. It was found that the novel life prediction method which was modified from Ong's method was suggested since almost all data have not been predicted well with the widely used methods. The suggested modified Ong's method predicted well within 3X scatterbands.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.7
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• pp.1039-1046
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• 2002

Co-flow axisymmetric laminar premixed flame of methane was used to study the influence of air temperature and $N_2$ addition on the flame structure, temperature field and emission characteristics. OH 2-D images and temperatures along the centerline were measured experimentally by PLIF and CARS techniques respectively to observe the influences of dilution and thermal effects of $N_2$ in the gas mixture. Also, the concentration of NOx was measured at each condition by gas analyser to see the suppression effect of N2 addition on NOx emissions. It was found that OH concentrations distribute widely as air temperature goes higher, while the effect of $N_2$ addition is not significant. But $N_2$ addition highly contributes to the flame front and NOx emissions which was argued to be due to the reduction of flame temperature. In accordance with experimental study, numerical simulation using CHEMKlN code was carried out to compare the temperature results with those acquired by CARS measurement, and we could find that there is good agreement between those results.

• Fire Science and Engineering
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• v.17 no.4
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• pp.7-12
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• 2003

The heat of combustion is one of the major physical properties used to determine the fire and explosion hazards of the flammable substances. Empirical equations have been developed to pre-dict the net heats of combustion of organic halogenated compounds based on the atomic contribution method. The method developed in this study was compared with Cardozo's method and Hanley's method. As can be seen from the average absolute deviation(A.A.D.), the proposed equation was found to be best. The proposed equation may serve as an estimation scheme for the heats of combustion of the other organic halogenated compounds.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.5
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• pp.634-640
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• 2011

The effect of cycling on the absorption and desorption characteristics of the 80 wt% $AB_2$-15 wt% Mg-5 wt% Mm system was investigated. The material was made by Hydrogen Combustion Synthesis. The cycling experiment was performed at 298 K, 30 atm for 15 min. During the reaction time, the amount of absorption was fully desorbed. After the full activation, the hydrogen storage capacity was 1.57 wt% and the capacity was maintained until 50 cycles. And the reaction rate does not change with an increase in the number of cycles. This material has good durability and reversible feature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.89-92
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• 2010

A study about the fatigue life of copper alloy which is used in inner jacket of regenerative cooling chamber of liquid rocket engine has been performed. Generally used life prediction methods-original universal slopes method, modified universal slopes method, Mitchell's method, Baumel and Seeger's method, and Ong's method-have been used for predicting the fatigue data. It was found that the novel life prediction method which is modified from Ong's method was suggested since almost all data have not been predicted well with the widely used methods. The suggested modified Ong's method predicted well within 3X scatterbands.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.5
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• pp.493-502
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• 2012

Syngas laminar burning velocity measurements were carried out at atmospheric pressure and ambient temperature using the Bunsen flame configuration with nozzle burner as a fundamental study on flame stability of syngas fuel. Representative syngas mixture compositions ($H_2$:CO) such as 25:75%, 50:50% and 75:25% and equivalence ratios from 0.5 to 1.4 have been conducted. Average laminar burning velocities have been determined by the stabilized nozzle burner flames using the angle method, radical surface area method and compared with the data obtained from the other literatures. And the results of each experimental methodologies in the various composition ratios and equivalence ratios were coincided with the result of numerical simulation. Especially, it was confirmed that there was necessary to choice a more accurate measurement methodology even the same static flame method for the various composition ratios of syngas fuel including hydrogen. Also, it was reconfirmed that the laminar burning velocities gradually increased with the increasing of hydrogen content in a fuel mixture.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.2
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• pp.53-59
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• 2019

LIBS plug, a simplified laser-induced breakdown spectroscopy(LIBS) device with the purpose of measuring the fuel distribution inside the combustion chamber, was developed and manufactured. The LIBS plug receives only two wavelengths (H:656.3 nm, O: 777 nm) that are closely related to the equivalence ratio in the overall spectrum. The calibration curve between the signal of the LIBS plug and the equivalence ratio was constructed, and the fuel distribution of gasoline-air and LPG-air mixtures was measured using the LIBS plug.