• 제목/요약/키워드: polyethylene gas pipe

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Study of Thrust Control Performance Improvement for Hybrid Rocket Applications (하이브리드 로켓의 추력제어 성능 향상에 관한 연구)

  • Choi, Jae-Sung;Kang, Wan-Kyu;Huh, Hwan-Il
    • Journal of the Korean Society of Propulsion Engineers
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    • v.15 no.1
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    • pp.55-62
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    • 2011
  • In this study, we tried to improve the thrust control performance through the thrust control combustion experiment of the hybrid rocket. We constructed the system which controls the oxidizer flow by combining a needle valve with a stepping motor and controlling the stepping motor drive according to the thrust control command order. Gas oxygen was used as the oxidizer for two different propellants, PE(Polyethylene), PC(Polycarbonate), respectively. To improve the slow response time and the oscillation phenomenon in the beginning stage of the thrust control combustion experiment, we measured and analyzed the change of the flow speed of the propellant pipe. The revised thrust control combustion experiment showed that the thrust was stably controlled with the margin or error from the thrust command within ${\pm}1$ N.

Experimental Study on Elastic Response of Circular Cross-section Slender Body to Forced Oscillation, Waves, and Current (복합 외력환경 중 원형 단면 세장체의 탄성응답에 관한 실험적 연구)

  • Park, Ji-won;Lee, Seung-Jae;Jo, Hyo-Jae;Hwang, Jae-Hyuk;Han, Sung-Hoon
    • Journal of Ocean Engineering and Technology
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    • v.30 no.2
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    • pp.91-99
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    • 2016
  • The global demand for oil and natural gas has increased, and resource development is moving to the deep sea. Floating and flexible offshore structures such as semi-submersible, spar, and FPSO structures have been widely used. The major equipment of floating structures is always exposed to waves, currents, and other marine environmental factors, which cause structural damage. Moreover, flexible risers are susceptible to an exciting force due to the motion of the floating body. The inline and transverse responses from the three-dimensional behavior of a floating structure occur because of various forces. Typical risers are made of steel pipe and applied in the oil and gas development field, but flexible materials such as polyethylene are suitable for OTEC risers. Consequently, the optimal design of a flexible offshore plant requires a dynamic behavior analysis of slender bodies made of the different materials commonly used for offshore flexible risers. In this study, a three-dimensional motion measurement device was used to analyze the displacements of riser models induced by external force factors, and forced oscillation of a riser was linked to forced oscillation under a steady flow and regular wave condition.