• Korean Journal of Food Science and Technology
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• v.4 no.3
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• pp.213-223
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• 1972

This paper chose the methods of methylesterification of the use of methoxide, the mixture solution of methanol-benzen-sulfuric acid in transesterification of the fat in cow's milk and modified powder milk and separated by gas liquid chromatography with F.F.A.P., D.E.G.A. as liquid phase. Quantitative analysis of the fatty acid of milk fat in cow's milk and modified powder milk was determined by gas liquid chromatography using the method of temperature programming which should be used to obtain satisfactory separation of short chain fatty acid on the chromatogram. It was found that the fatty acid composition of cow's milk and modified powder milk are all the major fatty acid of milk fat obtained by GLC analysis. Main components was found to be from butyric acid to arachidonic acid showing Fig. 3, 4, 5 and Table 4, 5, 6, 7, 8, 9.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.619-629
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• 1998

An experimental work was conducted to investigate a feasibility of simultaneous measurement of gas-liquid two-phase flowrates with double orifice plates using air and water. The tests were carried out under the atmospheric pressure and at the ambient temperature using two different tube sizes. Qualities of an air-water flow in the present study have values less than 0.1 and thus the mixed flow showed bubbly, plug, slug flow regimes. The probability density function (PDF) and the power spectral density function (PSDF) of the instantaneous pressure drop traces for the flow regimes were obtained. It is found that some distinctive features exist in the distribution of these functions, depending upon the two-phase flow pattern. The time-averaged value of the instantaneous pressure drop increases with increasing gas and liquid flowrates, showing a single-valued function for the total mass flowrate and the quality. It is also found that the two-phase discharge coefficient exhibits a consistent trend for variation of dimensionless parameters such as the superficial velocity ratio and the gas Reynolds number. The results indicate that simultaneous measurement of two-phase flowrate may be possible based upon a statistical analysis of the instantaneous pressure drop curves monitored using double orifice plates.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.726-728
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• 2010

A subscale gas generator was designed and manufactured to investigate the effect of design parameters on discharge coefficients of injectors for a 75 ton-class gas generator and hot-firing tests were successfully performed. The test results showed that discharge coefficients of fuel and liquid oxygen injectors remained nearly constant irrespective of variations of a mixture ratio and a chamber pressure. When the post diameter of the liquid oxygen injector was reduced, the discharge coefficient was increased as the pressure drop of the injector was decreased.

• Progress in Superconductivity and Cryogenics
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• v.25 no.4
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• pp.65-69
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• 2023

Hydrogen is an eco-friendly energy source and is being actively researched in various fields around the world, including mobility and aerospace. In order to effectively utilize hydrogen energy, it should be used in a liquid state with high energy storage density, but when hydrogen is stored in a liquid state, BOG (boil-off gas) is generated due to the temperature difference with the atmosphere. This should be re-condensed when considering storage efficiency and economy. In particular, large-capacity liquid hydrogen storage tank is required a gaseous helium circulation cooling system that cools by circulating cryogenic refrigerant due to the increase in heat intrusion from external air as the heat transfer area increases and the wide distribution of the gas layer inside the tank. In order to effectively apply the system, thermo-hydraulic analysis through process analysis is required. In this study, the condenser design and system characteristics of a gaseous helium circulation cooling system for BOG recondensation of a liquefied hydrogen storage tank were compared.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.509-512
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• 2006

The propellant mixture ratio of gas generator changes when thrust control valve operate to change LRE thrust level. The mixture ratio change of gas generator result in gas temperature change and failure of turbine blade or deterioration of LRE specific impulse. The mixture ratio stabilizer has been developed to maintain propellant mixture ratio of gas generator. This article deals with design and static/dynamic characteristic of stabilizer. Also gas generator system simulation test has shown that the stabilizer can maintain propellant mixture ratio effectively within tolerable range.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.560-564
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• 2004

The optimal design and combustion analysis of the gas generator for Liquid Rocket Engine (LRE) were performed. A fuel-rich gas generator in open cycle turbopump system was designed for 10ton$_{f}$ in thrust with RP-1/Lox propellant. The optimal design was done for maximizing specific impulse of main combustion chamber with constraints of combustion temperature and power matching required by turbopump system. Design variables were selected as total mass flow rate to gas generator, O/F ratio in gas generator, turbine injection angle, partial admission ratio, and turbine rotational speed. Results of optimal design show the dimension of length, diameter, and contraction ratio of gas generator. Also, the combustion test was conducted to evaluate the performance of injector and combustion chamber. And the effect of the turbulence ring was investigated on the mixing enhancement in the chamber.r.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.541-548
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• 2017

A theoretical study on gas-liquid two-phase flow flushing systemnitrogen gas to the oil used for existing flushing equipment was conducted on the basis of ISO code so as to improve performance of existing high-temperature oil flushing equipment used in ocean plant facility drying field. For study, we analyzed process simulation results mixed fluid mixing ratio, temperature, Reynolds number and liquid hold up affectcleaning performance after designing oil-nitrogen gas mixture flushing system process. As a result, as the volume flow rate of mixed fluid increases with the tube diameter the volume fraction of the gas phase constant, the liquid fraction difference value at the inlet and outlet of horizontal hydraulic piping increases. It was found that the phase distribution between oil and nitrogen gas bubbles varies depending on the position the pipe lengthdirection. This change in phase distribution is expected to have a significant impact on the clean performance of an oil-nitrogen gas mixture flushing system.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.25-30
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• 2000

In present paper, mass transfer over a flat plate with film condensation including noncondesable gas is analyzed with the help of similarity methods. Couette flow was assumed in liquid film and boundary-layer approximation was used in the ambient flow. Governing equations were transformed into the ordinary differential equtions by the similarity methods. Runge-Kutta and shooting method were used in order to fine the effect of mass transfer on the velocity and concentrations at the liquid-vapor interface.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.8 no.1
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• pp.10-13
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• 1979

The study for bubbling phenomena to influence heat transfer in gas - liquid contactors. The sparged contactor is gaining importance for gas-liquid chemical reactions. In this paper, correlations between Reynolds number and heat transfer coefficient were studied and experimental expressions were also obtained over broth of areas, namely, laminar area and turbulent area respectively.

• YAKHAK HOEJI
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• v.23 no.1
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• pp.7-10
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• 1979

A gas chromatographic determination of dienestrol in dienestrol cream has been studied. Dienestrol cream was dissolved in pyridine and silylation was done by using N, O-bis (trimethylsilyl) trifluoroacetamide. The derivative was injected into 3% silicone OV-17 column for chromatographic estimation. The dienestrol peak was found to be well separated from the other components of the cream. The detection limit was obtained to be $5.6{\times}10^{11}$ mol of dienestrol for this method. As there is no need for prior separation procedure, this experiment is extremely simple and less time consuming as compared to the conventional methods for estimation of dienestrol in cream.