• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.521-528
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• 2017

본 논문에서는 고체 로켓 추진기관에서 내열재 및 단열재로 사용되는 실리카/페놀릭 복합재료의 열 반응을 고려한 열전도 수치해석을 수행하였다. 고체 로켓 추진기관의 연소 중 실리카/페놀릭의 삭마와 열분해 과정을 고려한 열전도 해석을 위해 1차원 유한차분법을 이용하여 계산을 수행하였다. 노즐벽에서의 경계조건은 대류열전달계수를 고려하였으며, 이는 적분방정식을 이용하여 계산하였다. 삭마두께 및 숯깊이 해석결과는 목삽입재 평가 모터인 TPEM-10을 이용한 시험결과와 비교분석하였으며, 잘 일치하는 것을 확인할 수 있었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권6호
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• pp.321-327
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• 2000

FRP has been used very much as high strength and electrical insulation materials. The fiber contributes the high strength and modulus to the composite. The main roles of the matrix in composite materials like FRP are to transmit and distribute stresses among the individual fibers. The fiber orientation in FRP has a great effect on the strength of FRP because the strength of FRP mainly depends on the strength of fiber. In this study, compressive and bending stresses of FRP rods were simulated and measured according to the winding orientation of glass fiber. Inner part of FRP was made unidirectionally by pultrusion method and outer part of FRP was made by filament winding method to give fiber orientation to the FRP. The shear stresses had great effect on the strength of FRP although the stress of parallel direction of FRP was much higher. The tendency of compressive and bending strengths with glass fiber orientation was different each other.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.492-498
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• 2008

In this paper are described recent studies about variable nozzles, that are a rectangular type nozzle and an axisymmetric type nozzle, of the precooled turbojet engine(S-engine) which are developed for the demonstration of the key technologies for the propulsion system of the hypersonic airplane and the first stage propulsion of the TSTO space plane. For the rectangular nozzle, three types of C-shaped carbon/carbon composite cowls which includes subscale model of the precooled turbojet engine are fabricated and the fine attachment to the ramp is confirmed. For the firing of the S-engine, stainless steel cowl with concrete heat insulator are fabricated and tested for 20 sec. Axisymmetric variable plug nozzle which is made of C/C material is fabricated and pressurized by the cold flow test. The axisymmetric plug nozzle can be operative up to 0.57 MPa of nozzle inlet pressure.

• 전기학회논문지
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• 제68권1호
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• pp.61-68
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• 2019

Only the power is converted from AC to DC, in accordance with IEC 60587 based test method, in order to develop the LSR(Liquid Silicone Rubber) insulator material for HVDC, the experiment of Inclined Plate Tracking and Erosion Resistance was conducted. A contaminant (2.5 mS/cm: ammonium chloride) was applied at a rate of 0.3 ml/min and a voltage of ${\pm}3.5kV$, and was evaluated on the basis of 60 mA/2s. The samples were prepared by dispersing LSR/Nano silica_25wt% Composites in LSR. The erosion phenomena of surface discharge and tracking due to DC polarity and negative polarity were measured by image, leakage current maximum and thermal camera. The thermal imaging camera measured the surface temperature generated by the joule heat of the leakage current due to the drying discharge and the conductive current. After the measurement, the tracking and erosion mechanisms were evaluated for erosion weight, erosion depth and erosion length. Positive and negative polarity of LSR/Nano Silica_25wt% composite Tracking and erosion results show that positive polarity is more severe than negative polarity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1578-1580
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• 1999

Silicone rubber is being used for the housing material of outdoor high voltage insulators such as composite insulator, bushing, surge arrestor and cable terminator because of good tracking and erosion resistance, good hydrophobicity and recovery of hydrophobicity, and chemical stability. In this paper, tracking and erosion resistance of silicone rubber having fluids and different ATH contents were examined. Fluids were selected under the consideration of their molecular weight and chemical structure, expecting the high migration rate, the good pollutant encapsulation, and the long period with good hydrophobicity. Good tracking and erosion resistance and arc resistance have been achieved for the silicone rubber above ATH content 130 phr.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1232-1234
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• 1995

Specimem of silicone rubber used to make the weathersheds for High-Voltage composite insulator were aged in laboratory. The aging characteristics of silicone rubber have been assessed by compairing their hydrophobicity and electrical properties, before and after aging with weather ometer. Results show that their initial and time dependant characteristics are good.

• Transactions on Electrical and Electronic Materials
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• 제17권3호
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• pp.155-158
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• 2016

The effect of microsilica content modified with silicone-modified epoxy on electrical and mechanical properties of cycloaliphatic epoxy/microsilica system was investigated. The cycloaliphatic epoxy resin was diglycidyl 1,2-cyclohexanedicarboxylate and curing agent was an anhydride. Surface of microsilica was modified with silicone-modified epoxy. Electrical breakdown strength, the most important property for electrical insulation materials was tested. Tensile and flexural tests were also performed using universal testing machine (UTM). The microcomposite with 60 wt% microsilica shows maximum values in electrical breakdown strength.

• 한국초전도ㆍ저온공학회논문지
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• 제6권1호
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• pp.48-52
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• 2004

Breakdown characteristics of insulator-liquid nitrogen ($LN_2$) composite insulation for resistor type High $T_c$/ superconducting fault current limiter (HTSFCL) under ac and impulse voltage in $LN_2$ has been studied using model electrode systems. Electrodes for model electrode systems were made of SUS 304 contacted fiberglass reinforced plastic (FRP) and Au coated sapphire. The breakdown characteristics of model electrode systems were investigated experimentally for FRP thickness ranging from 1 mm to 5 mm. surface distance ranging from 2.5 mm to 7 mm and electrode gap ranging from 1 to 5 mm. The experimental data suggested that the breakdown voltage of model electrode systems in $LN_2$ is highly dependent on the surface distance, electrode gap as well as on the FRP thickness. Also, we had observed discharge traces and puncture due to high-voltage 60-Hz AC stress.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1450-1452
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• 1998

The chief advantage of polymer arrester, from a handling viewpoint, design of pressure relief, anti-contamination, electrical failuer was reduced by polymer arrester. The life expectancy of polymer arrester depend on a number of design factor. This paper introduced and study : new material housing (silicone composite, EPDM, EPA...), cap type sealing structure, knuckle type electrode, stress relief housing, supporting insulator and sub parts, of polymer arrester.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1440-1442
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• 2002

폴리머 애자는 여러 가지의 외부환경에 의하여 시간의 경과에 따라서 재료의 열화가 진행된다. 폴리머 애자를 평가하는 방법으로 기계적 특성, 전기적 특성, 환경적 특성 등의 평가방법이 있으나 각각의 특성평가에 있어서 국제, 국가 및 단체에 따라서 서로 다르다. 신뢰성 평가기준도 서로 달라 국내 실정에 맞는 폴리머 애자의 신뢰성 향상에 어려움이 있었다. 이러한 문제를 해결하기 위하여 폴리머 애자의 신뢰성 평가기준을 표준화할 필요성이 있다. 본 원고에서는 특고압 가공배전선로에 사용하는 폴리머 현수애자의 신뢰성 평가기준에 대하여 설명하였다. 장기신뢰성 평가를 위하여 다양한 외부환경을 모의하여 복합적인 스트레스를 가할 수 있는 복합가속열화설비에 대하여 설명하고 복합가속열화시험법을 결정하였다.