• Title, Summary, Keyword: Propulsion control device

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Development of an Underwater Rope-cutter Device and Controller for Removal of Propeller and Shaft Foreign Material for Small Vessel (소형선박용 프로펠러 및 샤프트 이물질 제거를 위한 수중절단기 기구 설계 및 제어기 개발)

  • Lee, Hunseok;Oh, Jin-Seok;Choi, Sun-Hong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.7
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    • pp.927-935
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    • 2019
  • Screw-failure accidents in small ships frequently occur in coastal waters. In particular, vessels' propulsion systems are frequently coiled due to objects such as fish-nets and ropes that float on the sea. The failure of the ship's propulsion system can cause primary accidents such as ship operation delays and drifting due to loss of power; furthermore, the possibility of secondary accidents such as those involving operators in the underwater removal of rope stuck in a propeller. Ships that do not have the proper tools to solve these problems must be either lifted onto land to be repaired or divers must dive directly under the ship to solve the problem. Accordingly, some small vessels have been equipped with rope-cutter devices on the propeller shaft to prevent ship propeller system accidents in recent years; however, they are not being applied efficiently due to the cost and time of installation. To solve these problems, this study develops an underwater rope-cutter device and controller for the removal of propeller and shaft foreign material in small vessels. This device has simple structures that use the principle of a saw. Meteor gears and crank pins were used for the straight-line rotation of saw blades of the underwater rope-cutters to allow for long strokes. Furthermore, the underwater rope-cutting machines can be operated by being connected to the ship battery. The user, a non-professional, can ensure convenience and stability by applying reverse current prevention and a speed control circuit so that it can be used more conveniently and safely.

Spray Characteristics of a Modulated Liquid Jet through 2nd Pulsed Control (2차 가진 제어 변조분사 특성 및 액체제트의 분무특성)

  • Kang, Young-Su;Lee, In-Chul;Koo, Ja-Ye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.672-675
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    • 2010
  • Spray characteristics for the modulation with a pulsed spray in low-frequency region were investigted by performing with additional internal pulsed injection. The 1st perturbative flow was generated by rotating-type pulsed device and the 2nd pulse source generated by the magnetic valve was used to modulate the 1st flow. A pattern of the modulated spray was observed through FFT result and visualization. In case of modulated spray with the 2nd pulse control, the width of up and down motion of the modulated spray is smaller than that of the spray without the 2nd pulse. Also, the depth of penetration of the down stream is higher than that of spray without the 2nd pulse.

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A Study on Dynamic Performance and Response of Turbo Shaft Engine for SUAV (스마트 무인항공기용 터보축 엔진의 동적성능과 응답성에 관한 연구)

  • Park J. C.;Lee D. W.;Roh T. S.;Choi D. W.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.201-204
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    • 2004
  • In this study, the GSP and in-house numerical codes have been used for analyses of the on-design, static off-design and dynamic off-design performances. Through the various missions including altitude, velocity, and power variations static engine performance have been investigated. The dynamic engine performances based on these complicated variations have been also analysed. Especially, the power, engine rpm and heat overload characteristics of a turbine have been estimated with the response time through the control of a throttle setting rather than a power setting. It could be applied to the FADEC system as an engine control device.

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A Study on Dynamic Performance and Response of Turbo Shaft Engine for SUAV (스마트 무인항공기용 터보축 엔진의 동적성능과 응답성에 관한 연구)

  • Park Jun-Cheol;Roh Tae-Seong;Choi Dong-Whan;Yang Soo-Seok
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.2
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    • pp.17-24
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    • 2005
  • In this study, the GSP and in-house numerical codes have been used for analyses of the on-design, static off-design and dynamic off-design performances. Through the various missions including altitude, velocity, and power variations the static engine performance have been investigated. The dynamic engine performances based on these complicated variations have been also analyzed. Especially, the power, engine rpm and heat overload characteristics of the turbine have been estimated with the response time through the control of the throttle setting rather than the power setting. It could be applied to the FADEC system as an engine control device.

Performance and Sensitivity Analysis of Disk-type Fluidic Control System (디스크형 유체역학적 방향제어 시스템 성능해석 및 설계 인자 민감도 분석)

  • Cho, Mingyoung;Han, Doohee;Sung, Hong-Gye;Choi, Hyun Yung
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.3
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    • pp.103-110
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    • 2016
  • A performance analysis program of a disk type fluidic valve was developed to predict a chamber pressure and a response time. A parametric study of this device was performed by using scattering plot method. A sensitivity of Mach number at a nozzle outlet showed the highest value about a outlet diameter of nozzle. An inlet flow rate is the most important parameter to design the fluidic valve because it has high sensitivity value both a outlet velocity and a response time.

Rupture Prediction of the Rupture Disk Using Elasto-Plastic Analysis (탄소성해석을 이용한 파열판의 파열예측)

  • Han, Houk-Seop;Lee, Won-Bok;Koo, Song-Hoe;Lee, Bang-Eop
    • Journal of the Korean Society of Propulsion Engineers
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    • v.16 no.3
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    • pp.49-56
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    • 2012
  • Rupture disks are a kind of safety device in high pressure equipment and they are used to control rupture pressure in the solid rocket motor. In this paper, a series of rupture experiments was performed using rupture disks made of AISI 316L and rupture pressure of rupture disks was calculated through various assumptions in relation between elasto-plastic material properties and true stress-strain curve. Experiment and FEA indicated rupture pressure is determined by size of rupture disks. As a result of elasto-plastic analysis, only multi-linear stress-strain curve was able to calculate meaningful estimations. Experimental results also showed rupture location are decided by the size of rupture disks. Experimental and FEA results will be applied to control rupture pressure of disks.

Operation and Result Analysis of Hydraulic Vehicle Holding Device (발사체 지상고정장치 유압시스템 작동 시험 및 결과 분석)

  • Kim, Dae Rae;Yang, Seong Pil;Lee, Jae Jun;Song, Oh-Seob;Lee, Young-Shin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.1
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    • pp.80-88
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    • 2018
  • The function of a vehicle holding device (VHD) is to securely hold a launch vehicle on the launch pad and release the launch vehicle at maximum thrust after engine ignition to allow lift-off of the launch vehicle. During the release of the launch vehicle, to prevent the Ka doing a doing a doing mode, which is the vertical oscillation of the entire liquid propellant, the release of the launch vehicle should be gradual. In this study, for the gradual release of a launch vehicle, a hydraulic system comprising an accumulator and pyro valve to operate a hydraulic cylinder and control the speed of the cylinder with an orifice is introduced. Through a test, the influence of design variables on the cylinder speed is analyzed. Based on this, the design values of the hydraulic cylinder are determined. Through this study, the engineering basis for developing a VHD releasing a launch vehicle at maximum thrust is provided.

A Development of Integrated Control System for Platform Equipments of Unmanned Surface Vehicle (USV) (무인수상정 플랫폼 장비의 통합 제어 시스템 개발)

  • Hwang, Hun-Gyu;Kim, Hyun-Woo;Kim, Bae-Sung;Woo, Yun-Tae;Shin, Il-Sik;Shin, Ji-Hwan;Lee, Young-Jin;Choi, Byung-Woong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.8
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    • pp.1611-1618
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    • 2017
  • Recently, the development for USV-related technologies are actively growing up in military domain. The USV (unmanned surface vehicle) conducts various missions for national defense at maritime environment. For succeed the missions, the USV essentially needs an automatic and remote control platform which includes propulsion system, steering system, control system, power system and so on. In this paper, we developed an integrated control system for the platform equipments and verified effectiveness of the developed system. To do this, we designed a system architecture and implemented a main control system that processes and controls platform equipments by received command. Also we developed components of designed architecture such as engine control device, water-jet control device and power control device. For test and verify the developed system, we designed and made a test-bed of engine and water-jet with related parts, and proceeded a basin test for verifying the developed system based on the test-bed.

Experimental/ Computational Study on the Passive Control of Supersonic Cavity Flow using a Sub-Cavity (Sub-cavity를 이용한 초음속 cavity 유동의 피동제어에 대한 실험 및 수치해석적 연구)

  • Lim, Chae-Min;Lee, Young-Ki;Kim, Heuy-Dong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.295-298
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    • 2007
  • The effectiveness of passive control techniques for reducing the pressure oscillation generated in a supersonic cavity flow was investigated numerically and experimentally, respectively. The control device includes a sub-cavity installed in the upstream edge of a rectangular cavity. Time-dependent supersonic cavity flow characteristics with turbulent features were examined by using the three-dimensional, mass-averaged Navier-Stokes computation based on a finite volume scheme and large eddy simulation. The results show that the pressure oscillation near the trailing edge dominates overall time-dependent cavity pressure variations. Such an oscillation can be attenuated more significantly in the presence of the sub-cavity compared with the cavity without sub-cavity, and a larger sub-cavity leads to better control performance.

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Reliability Prediction of Electronic Arm Fire Device Applying Sensitivity Analysis (민감도 해석을 적용한 전자식 점화안전장치의 신뢰도 추정)

  • Kim, Dong-seong;Jang, Seung-gyo;Lee, Hyo-Nam;Son, Young Kap
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.5
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    • pp.393-401
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    • 2018
  • Reliability prediction of an electronic arm fire device(EAFD) was studied which is applied to prevent accidental ignition in a solid rocket motor. For predicting the reliability, the main components of the EAFD were first defined(Control unit, LEEFI, TBI) and the operating principle of each component was analyzed. Performance modeling of each part is established using selected input variables through system analysis. When complex analysis is required, we approximated it with polynomial equation using response surface method. Monte-Carlo simulation is applied to performance modeling to estimate the design reliability.