• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.13-18
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• 2010

This study aim to investigate the internal mixing flow characteristics by recess length of swirl coaxial injector for gas generator has propellant of Kerosene-LOx. Recess length is a very important element, have influence in spray stability and LOx post damage. The influence of recess length was analyzed by visualizing internal flow and measuring liquid film thickness and manifold pressures. Also, frequency characteristics were analyzed by liquid film thickness measurement with mixing time.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1092-1098
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• 2004

Today the demand of the optical communication components has been increased. Zirconia Ferrule has become the one of the most important elements because it determines transmission efficiency and quality of information in the optical communication system. Grinding is the major process in the ferrule manufacturing process which require high processing precision. In this reseach, specially designed spindle, chucking system, loading & unloading system and cooling system, as a supporting experimental equipment for development of an Intelligent Coaxial Grinding System (ICGS) for Zirconia Ferrule processing, is developed. We are also analized the adaptability of ICGS in practical use, through the way of evaluation for the performance of the each systems above.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2175-2180
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• 2008

Oxy-fuel combustion has been gaining its significance as a means of migrating the green house effects. Some experimental measurements were conducted to investigate the characteristics of oxy-fuel combustion and to aid a fundamental design of a lab-scale oxy-fuel combustor with a coaxial burner. CO emission was measured along the combustor centerline while combustion of methane and oxygen diluted by CO2 took place. Substitution of CO2 with N2 indicates a possibility that some CO is formed by dissociation of CO2. Some parametric tests were also performed to see the mixing effects of reactant gases on CO emission by changing the gas injection velocity at the burner nozzles with various heat loads. The overall results indicate that CO emission was reduced when the reactants are injected at higher velocities of similar magnitude.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.29-33
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• 2010

This study aim to investigate the internal flow characteristics by recess length of swirl coaxial injector for gas generator has propellant of Kerosene-LOx. Recess length is a very important element, have influence in spray stability and LOx post damage. The influence of recess length was analyzed by visualizing internal flow and measuring liquid film thickness and manifold pressures. Also, each spray characteristic by recess length was investigated in internal or external injector.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.3
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• pp.378-385
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• 1998

A three-dimensional finite difference time domain (3-D FDTD) algorithm of calculation for the characteristics of coaxial-to-cavity filter including a discended probe and a tuning post is presented. In the arrangement the inner coaxial conductor protrudes into the cavity and operates as a probe radiator. And the height of the rectangular tuning post determines the resonant frequency. The validation of this method is confirmed by comparing the calculated values with experimental results for the designed filter.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.933-942
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• 1992

The effects of the folwrate on the dropsize from the two-phase coaxial nozzle are investigated by using the direct photographic method and the empirical equation is obtained. For the photography, the light source which the life time is the order of 100ns is fabricated and the lens is the zoom lens which has the MICRO function with a teleconvertor. The distillated water and the compressed air of the surrounding temperature are injected and atomized. For the purpose of the exact adjustment and measurement of the flowrates, the two rotameters are used. As a result of this study, the sauter mean diameter of droplets has a tendency for a logarithmic function with air flowrate and for a exponential function with water flowrate.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.261-266
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• 1997

Nonevasive multifrequency microwave radiometry using coaxial waveguide antenna has been investigated for a homogeneous and four layer human body model. The coupling between coaxial waveguide antenna and a biological object was analyzed by use of the finite-difference time-domain(FDTD) method to obtain the absorbed power patterns in the media. The object studied in this paper was a homogeneous and four-layered lossy medium. The specific absorption rates(SAR) distribution which was corresponding to the temperature distribution was calculated in each region by use of the steady-state response in FDTD method. The SAR pattern of 1.2GHz was compared with that of 1.8GHz.

• Journal of the Korean Society of Combustion
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• v.21 no.2
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• pp.15-21
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• 2016

Flame characteristics and combustion stability of a swirl coaxial injector are studied experimentally. Characteristics of flame and combustion instability are analyzed with the parameter of MFR (momentum flux ratio) using hexane instead of kerosene. Flame patterns of blue and yellow are changed with variable MFR. Combustion instabilities are measured and analyzed by adopting a model chamber. Combustion instability mapping is made by evaluating damping factor at the 2 L (second longitudinal) mode with variable MFR in 63 cases for operating condition.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.185-188
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• 1996

Noninvasive multifrequency microwave radiometry using coaxial waveguide antenna has been investigated for a homogeneous and four layer human body model. The coupling between coaxial waveguide antenna and a. biological object is analyzed by use of the FDTD method to obtain the absorbed power patterns in the media. The object studied in this paper is a homogeneous and four-layered lossy medium. The specific absorption rates(SAR) distribution is calculated in each region by use of the steady-state response in FDTD method.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.274-277
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• 1994

This paper describes a very fast rising high voltage pulse generation for studying surge phinomenon and prebreakdown of liquid dielectric by appling the traveling wave theory of the distributed circuit. This very fast rising high voltage pulse generator consists of a charging coaxial cable, a discharging switch, and a terminating resistance. As results, the rising time of pulses are about 31(nsec), which is very fast, and its duration is 950[nsec] when using 200[m] coaxial cable. The length of the coaxial cable and changing voltage can regulate the duration and the amplitude or the polarity of the pulse. When terminated the resistance, capacitor and inductor, the measured waveform corresponds with simulated waveform.