• Journal of the Korean Society of Propulsion Engineers
• /
• v.21 no.6
• /
• pp.91-102
• /
• 2017

The early basic studies on RDE has been surveyed in the previous paper. Recently active researches are carrying on for the application to the power plant and aerospace propulsion systems. Collaboration researches are going on for the application of RDE for the gas turbine, liquid rocket and combined cycle engines in many countries. Following the previous Part 1 paper, present paper is intended to provide the comprehensive survey of recent worldwide efforts on the realistic application of RDE.

• Journal of the Society of Naval Architects of Korea
• /
• v.35 no.1
• /
• pp.98-106
• /
• 1998

This paper shows the temperature distribution of double hull compartment and of cofferdam in a large LNG Carrier. In LNG Carrier, due to the lower cargo temperature($-163^{\circ}C$), structures are forced to lose their strength if additional heat is not supplied. So it is very important to estimate the temperature distribution and the heat flux needed to maintain the structure properly. The temperature of each compartment is obtained using 2-dimensional model analysis and compared with 3-dimensional results. And also this paper gives preliminary estimation of pipe length to supply necessary heat flux in bare pipe and finned pipe.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.160-162
• /
• 2017

When rubber elastomer has contact with fuel, since the component and additive having low molecular weight can flow out, the physical properties of both elastomer and fuel could be hindered. In order to predict the life of the rubber elastomer, this study is to determine the change of weight, thickness, hardness, strain, and compression set as mechanical properties of the sealant rubber O-ring, which was dependent on volume, temperature, and storage time of the contacted fuel. We also determined purity of fuel via GC analysis and measured gross heat of combution. The results could be used as a reference to evaluate the life of the rubber elastomer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.05a
• /
• pp.206-209
• /
• 2002

본 논문에서는 폴리실리콘의 재결정화 공정에서 발생하기 쉬운 폴리실리콘의 엉김현상, 슬립, 부분적인 실리콘 기판의 녹음현상 등을 방지하기 위한 방법을 제시한다. 그리고 재결정화 된 박막의 질을 향상시키기 위한 폴리실리콘과 보호 산화막(capping oxide)의 두께 변화에 따른 실험 결과를 살펴본다. 폴리실리콘의 엉김현상은 매몰 산화막(buried oxide)과 액체 상태의 실리콘 사이의 wetting angle과 관계되는데, 이를-방지하기 위해서는 재결정화할 폴리실리콘과 산화막의 계면에 질소를 주입시켜주면 되는데, 이는 재결정화할 시료를 암모니아 가스 분위기에서 열처리를 통하여 해결할 수 있다. 그러고 실러콘 기판의 국부적 녹음 현상 및 슬립은 실리콘 기판의 윗면을 mechanical damage에 의해서 약 $20{\mu}m$ 정도의 거칠기를 가지도록 하면 이러한 현상을 방지할 수 있다. 그러고 폴리실리콘이 재결정활 될 때 부피의 변화가 발생하며, 이로 인하여 재결정화된 박막의 두께는 위치에 따라 변화한다. 재결정화된 박막 두께의 균일도를 유지하기 위해서는 재결정화할 폴리실리콘 두께의 3배 이상이 되는 보호 산화막을 사용하였을 때 원하는 균일도를 얻을 수 있었다.

• 월간 기계설비
• /
• s.266
• /
• pp.49-57
• /
• 2012

지난 8월 13일 서울 종로구 소격동 국립현대미술관 서울관 공사현장에서 화재 발생으로 4명이 숨지고 18명이 중경상을 입는 등 많은 인명피해를 냈다. 이처럼 인명피해가 컸던 것은 우레탄 공사를 하던 밀폐공간에서 불이 나면서 발생한 유독가스 때문에 사람들이 제대로 대피하지 못했기 때문이다. 사고발생 원인으로 '용접공사' 여부를 놓고 공방을 벌였으나 경찰은 '전기합선'이라는 잠정 결론을 내렸다. 지난 2008년 1월에 발생한 경기도 이천 냉동창고 화재는 40명의 목숨을 앗아갔다. 화재 원인은 냉동배관을 설치하면서 전기 용접을 하기 위해 불을 붙였다가 이것이 공기 중에 차 있던 유증기(기름증기)와 만나면서 폭발이 일어난 것이었다. 올 여름처럼 기온이 높고 건조한 날이 지속되면서 인화성 액체(유기용제)를 취급하는 건설현장에서는 다량의 유증기가 발생할 수 있을 뿐만 아니라 건조한 조건에서 정전기에 의한 화재 폭발 누출사고의 발생 위험이 높아지고 있다. 기계설비공사에서 화재, 폭발 위험성이 가장 큰 공사는 용접공사이기에 용접공사를 할 때 화재, 감전의 위험성을 배제한 후 공사에 들어간다. 용접으로 인한 사망사고의 유형으로는 용접 중 추락사고와 더불어 용접 불꽃이 가연성 물질에 옮겨 붙어 화재 발생으로 인한 질식사, 용접작업 중 절연체가 파손된 용접기 홀더 충전부의 접촉으로 인한 감전사 등이 있다. 본지는 용접으로 인한 화재 감전 등의 사고발생을 미연에 방지하기 위해 안전작업 수칙 및 안전수칙 체크리스트, 재해사례를 시리즈로 연재한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.10a
• /
• pp.121-125
• /
• 2004

The effectiveness of the pogo suppression device (PSD) installed at the piping system simulating the fuel supply lines of the rocket engines was investigated. The system response defined as the ratio of the flow rate to the pressure in the main tube was obtained for various PSD gas volumes $(0,\;0.5,\;1,\;2\times10^{-6}\;m^3)$. Existence of a gas volume in the PSD reduced the system resonance frequency. With a larger gas volume, the resonance frequency became lower, but only slightly, though the fluctuations of the main tube pressure and the flow rate damped down considerably

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.153-156
• /
• 2008

Ignition and combustion performance of a gas-turbine engine were changed by various high-altitude condition. A goal of this study is to make the small test facility to simulate high-altitude condition. To perform the low pressure condition, a diffuser was used in various diffuser front of primary nozzle pressure. To perform the low temperature, heat exchanger was used in various mixture ratio of cryogenic air and ambient temperature air. The experimental result shows that high-altitude conditions can be controled by diffuser front of primary nozzle pressure and mixture ratio of cryogenic air and ambient temperature air.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.175-178
• /
• 2008

Spray characteristics for the simplex atomizer are investigated. The atomizer was tested with kerosene which is generally used as a fuel for gas turbine engines. But it is very difficult and dangerous to measure spray performance. So water is used as a working fluid for measuring the droplet information. In this study, spray visualization was performed by using ND-Yag Laser and droplet size was measured by using PDPA system by using two different working fluid such as water and test fluid # 2 which has similar characteristics of the kerosene. The test results show that SMD of water bigger than test fluid # 2 about 5$\sim$15 mm because surface tension of water is higher by a factor of 3. But the spray angles and the spray shapes have similarity

• Journal of the Society of Naval Architects of Korea
• /
• v.46 no.6
• /
• pp.650-658
• /
• 2009

Two dimensional sloshing phenomena in regularly excited liquid cargo tank are numerically simulated with finite difference method. Navier-Stokes equations and continuity equation are computed for this study. The free-surface is determined every time step satisfying kinematic boundary condition using marker-density method. And the exciting force is treated by adding the acceleration of the tank to source term. The results are compared with other existing experiment results. And the comparison results show a good agreement. The sloshing phenomena in the tank of the 138K LNG carrier in sway motion is simulated with present calculation methods in low filling level. To find the relations between impact pressure and excitation condition, the calculations are performed in various amplitudes and periods. The averaged maximum pressures are compared each other.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.24 no.6
• /
• pp.108-119
• /
• 2020

Dynamic pressure sensor used in liquid rocket engine combustor and gas turbine is recess-mounted usually because it should work in high temperature environment. Although recess-mounted method can protect it from combustion gas in high temperature, tube resonance occurs in a tube-cavity system. To reduce it, the infinite tube probe(ITP) was introduced in this study. The ITP model suggested in previous literature was validated with experimental data and frequency response characteristics were analyzed. Guidelines for designing the ITP were suggested as frequency response profiles varied with geometric information and physical properties using this model.