• Title/Summary/Keyword: 구동압력

Search Result 351, Processing Time 0.031 seconds

Numerical Study on The Pressure Drop of Immiscible Two-Phase Flow in The Pressure Driven Micro Channel Using Lattice Boltzmann Method (Lattice Boltzmann 방법을 이용한 압력구동 미세채널 내 비혼합 2상 유체 흐름의 압력강하에 대한 수치적 연구)

  • Jeong, Soo-In;Kim, Kui-Soon;Kang, Beom-Soon
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2008.03b
    • /
    • pp.436-439
    • /
    • 2008
  • Computer simulation of multiphase flows has grown dramatically in the last two decades. In this work, we have studied the flow characteristics of immiscible two fluids in a 2-D micro channel driven by pressure gradient using multi-phase lattice Boltzmann method suggested by Shan and Chen(1993) considering the fluid-surface interaction. we tried to examine the effects of parameters related to the two phase flow characteristics and pressure drop in the micro channel like contact angle and channel configuration by changing their value. The results of current study could show the lattice Boltzmann method can simulate the behaviors of two phase flow in the region of micro fluidics well.

  • PDF

High Efficiency Fuel Cell System with Air Amplifier using Waste Heat (배열이용 공기증폭기를 활용한 고효율 연료전지 시스템)

  • Jun, Jaeho;Choi, Youngjae;Jun, Joonghwan;Kim, Seontae;Kim, Seongwan
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2010.11a
    • /
    • pp.72.1-72.1
    • /
    • 2010
  • 지금까지 연료전지 시스템의 효율을 극대화시키기 위한 기술들이 개발되어 왔는데, 대표적인 방법은 CHP(Combined Heat & power)와 FCT(Fuel cell & Turbine) Hybrid 시스템이다. 그러나 본 연구의 기술은 연료전지 배열을 이용한 Coanda 공기증폭기를 장착한 새로운 개념의 고효율 연료전지 시스템이다. 원래 공기 증폭기는 완만한 곡면 주위를 흐르는 유체가 곡면의 표면을 따라 흐름의 방향이 바뀌는 원리(Coanda Effect)를 이용한 장치로서, 소량의 고압유체를 구동 에너지원으로 사용하여 최고 20배에 해당하는 많은 양의 주변 유체를 빠른 속도로 이송시키는 역할을 한다. 문제는 고압의 유체원을 만드는 것인데, 본 연구에서는 발전용 연료전지 시스템의 배기가스를 활용하여 먼저 고압의 수증기를 발생시키고, 다음으로 고압의 수증기를 공기 증폭기의 구동원으로 사용함으로써 연료전지 시스템의 Air blower를 대체하는 것이다. 이러한 개념을 검증하기 위해서 고압의 스팀작동 Coanda 공기증폭기를 제작하여 선행실험을 진행하였다. 먼저 공기증폭기의 Gap 및 스팀압력에 따른 공기유량, 압력 등의 기본특성을 조사하였고, 출력 공기의 특성을 개선하기 공기증폭기의 형상 및 재료를 새롭게 설계하였다. 그리고 실제 시스템의 적용가능성을 알아보기 위해서, 예로 300kW급 용융탄산염 연료전지 발전시스템의 Air blower 대체가능성을 확인하였고, 배열이용 Coanda 공기증폭기를 활용한 고효율 연료전지 시스템의 개념설계를 수립하였다. 결론적으로 본 기술을 활용하면 연료전지 시스템의 최종 전기효율을 향상시킬 뿐 아니라는 시스템의 장기 신뢰성을 증대시키는 효과를 기대할 수 있다.

  • PDF

Implementation of Intellectual Noninsertion Kegel Trainer (지능형 비삽입식 요실금 치료기의 구현)

  • Yoon, Dal-Hwan;Yeun, Sang-Ho;Kang, Byung-Mo
    • The Journal of the Institute of Internet, Broadcasting and Communication
    • /
    • v.13 no.1
    • /
    • pp.9-18
    • /
    • 2013
  • In this paper, we have developed the intellectual kegel trainer with the biofeedback. The pelvic muscles of female are composed of a slow twitch fiber and a fast twitch fiber. If two twitch fiber be not well done, then the urine be frequently called by nature. In order to recover the function of pelvic muscles, we use the kegel trainer with biofeedback training. Such a trainer make strengthen the weakness pelvic muscles by biofeedback training and get exercise the pelvic muscles in physical suppress of 10 kg. The biofeedback training against the physical suppress can have strengthen the pelvic muscles and can display the operation graph of strengthen movement in monitor.

CdSe/ZnS 양자점 전계발광소자에서 전하수송층인 Zinc Tin Oxide의 비저항이 소자의 발광 특성에 미치는 영향

  • Yun, Seong-Ryong;Jeon, Min-Hyeon;Lee, Jeon-Guk
    • Proceedings of the Materials Research Society of Korea Conference
    • /
    • 2011.10a
    • /
    • pp.44-44
    • /
    • 2011
  • Unipolar 구조의 양자점 발광소자는 소자에 주입되는 전자로 구동 가능하게 설계되어 bipolar 구조와 달리 직류뿐만 아니라 교류로도 구동이 가능하다. 소자의 구조는 패턴된 ITO 유리기판 위에 Radio frequency magnetron sputter로 성장시킨 투명한 금속산화층 사이에 콜로이드로 분산된 양자점이 포함되어 있다. 본 연구에서는, 전하 수송층으로 사용되는 Zinc Tin Oxide (ZTO)가 전압 인가 시 발생하는 과부하로 인해 낮은 전계발광(electroluminescence, EL)특성이 나타나는 문제점이 있다. 이를 해결하고자 ZTO층의 비저항과 EL특성 사이의 관계를 알아보고, ZTO의 비저항 값을 변화시키기 위해 sputter 공정 중 인가 전력과 작업압력, 산소 분압 등의 성장 조건을 변화시켰다. ZTO의 조성비에 따른 비저항 및 전기적 특성을 홀 측정 장비로 측정하였다. 인가전력이 낮고 작업압력이 낮을수록 비저항 값이 낮았으며, 그에 따라 소자의 동작전압이 낮아지고 EL특성 또한 우수하게 나타났다.

  • PDF

The structural characteristics of ZnO thin films for TFT driver circuit (박막트랜지스터 구동회로용 ZnO 박막의 구조적 특성에 관한 연구)

  • Son, Jihoon;Kim, Sanghyun;Kim, Hongseung;Jang, Nakwon
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.37 no.1
    • /
    • pp.72-77
    • /
    • 2013
  • The effect of sputtering condition on the structural properties of ZnO thin films grown by RF magnetron sputtering system was investigated for TFT driver circuit. ZnO thin films were grown with ZnO target varying RF power and working pressure. Structural properties were investigated by X-ray diffraction (XRD) and atomic force microscope (AFM). The ZnO thin films have sufficient crystallinity on the 100W RF power. But, the surface roughness of ZnO films was increased as increased RF power. As increased working pressure from 5 mTorr to 15 mTorr, a full width at half maximum (FWHM) of ZnO (002) peak was increased.

Seismic Qualification Test for SSDM Hydraulic System of Research Reactor (연구용 원자로 이차정지구동장치 수력시스템의 내진검증)

  • Kim, Sanghaun;Kim, Gyeong-Ho;Sun, Jong-Oh;Cho, Yeong-Garp;Jung, Taeck-Hyung;Kim, Jung-Hyun;Lee, Kwan-Hee
    • Transactions of the Korean Society of Pressure Vessels and Piping
    • /
    • v.12 no.1
    • /
    • pp.23-29
    • /
    • 2016
  • The Second Shutdown Drive Mechanism (SSDM) provides an alternate and independent means of reactor shutdown. The Second Shutdown Rods (SSRs) of SSDMs are poised at the top of the core by the hydraulic force driven from a hydraulic system during normal operation. The rods drop by gravity when a trip is commended by a Reactor Protection System, Alternate Protection System, Automatic Seismic Trip System or operator by means of power off solenoid valves of hydraulic system. This paper describes the test results of seismic qualification of a prototype SSDM hydraulic system to demonstrate that its structural integrity and operability (functionality) are maintained during and after seismic excitations, that is, an adequacy of the SSDM design. From the results, this paper shows that the SSDM hydraulic system satisfies all its design requirements without any malfunctions during and after seismic excitations.

Improving Stability of Motor Generator Set of the Power Supply System for CEDM in Korean Standard Nuclear Power Plants (한국표준형 원전 제어봉구동장치 전원공급계통의 전동발전기 세트 안정성 개선)

  • Choi, Il Young;Kim, Jin Weon
    • Transactions of the Korean Society of Pressure Vessels and Piping
    • /
    • v.12 no.1
    • /
    • pp.49-55
    • /
    • 2016
  • This paper analyzed a root cause of abnormality in the temperature and vibration at generator-side bearing of motor generator set (MG Set), which is a power supply system to control element drive mechanism (CEDM) of nuclear power plants (NPPs), and modified the design of roller-type and sealing method to improve the abnormalities. From the inspection of MG Set and analysis of temperature variation during service, it was found that the abnormal temperature transition was basically associated with original design of generator-side bearing, whose roller was axially restrained by inner race, and that the abnormal vibration level was caused by inserting small chips of cage and V-ring, which were generated due to the abnormal temperature transition at roller bearing. Type of bearing and sealing method were modified based on these analyses. The temperature and vibration level measured at roller bearing showed that the modifications clearly improved the operational stability of MG Set.

A Study on Optimal Design of Direct Needle-driven Piezo Injector for Accomplishing Injection Pressure of 1800 bar (분사압력 1800 bar 실현을 위한 직접 니들구동방식 피에조 인젝터 설계 최적화 연구)

  • Han, Sangik;Kim, Juhwan;Ji, Hyungsun;Go, Junchae;Kim, Jinsu;Lee, Jinwook
    • Journal of ILASS-Korea
    • /
    • v.21 no.3
    • /
    • pp.121-129
    • /
    • 2016
  • The advantages of the common rail fuel injection system architecture have been recognized since the development of the diesel engine. In common rail systems, a high-pressure pump stores a reservoir of fuel at high pressure up to and above 2000 bar. And solenoid or piezoelectric valves make possible fine electronic control over the fuel injection time and quantity, and the higher pressure that the common rail technology makes available provides better fuel atomization. In this study, the direct needle-driven piezo injector was investigated for accomplishing injection pressure of 1800 bar by optimal design by simplification of component and changing number of springs and plates of DPI. It was found that a direct needle-driven piezo injection system features the prototype DPI for passenger vehicle to operate at 1800 bar of injection pressure.

Microchannels for the Flow Control of Two Fluids with Different Volumes (부피가 다른 두 유체의 효과적인 유동제어를 위한 미세채널)

  • La, Moon-Woo;Ho, Jae-Yun;Kim, Dong-Sung
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.36 no.1
    • /
    • pp.89-95
    • /
    • 2012
  • In this paper, microchannels for the flow control of two fluids with different volumes have been designed, fabricated, and verified. The dimensions of the inlets were determined based on the Stokes equation in order to realize that the flow of the two fluids meet at the same time, and to maintain a certain configuration when the flows passed through each inlet channel. The designed microchannels were confirmed using computational fluid dynamics simulation for the incompressible, Newtonian, and transient flows. In addition, a microfluidic system containing the designed microchannels was fabricated by soft lithography, and the pressure-driven flows of the two fluids were characterized by microfluidic experiments.

A Study on the Stability of Torque for Compressing-Cutting Device of Nano Tube Manufacturing System Using DC Servo Motor (DC 서보모터를 이용한 나노튜브 제조용 압축-절단 장치의 토크 안전성에 관한 연구)

  • Choi, Kab-Yong;Oh, Tae-Il
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.12 no.12
    • /
    • pp.5393-5397
    • /
    • 2011
  • The compressing-cutting device is used for manufacturing nano tube. the purpose of this study is to design and manufacture the compressing-cutting device witch has safety and stable performance. The most important core technology, in nano tube manufacturing, is to seam the each end of tube with appropriate pressure and to cut it off into the two part safely not to leak injected medium. Since the compressing pressure and the cutoff speed make the quality of nano tube, they are very important. This study will show the processes of design and manufacturing of compressing-cutting device.