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DTP 시스템에서의 전단형 피에조 잉크젯 프린트헤드의 액적거동 해석
김길동(Gildong Kim),박종훈(Jonghoon Park),신경(Kyung Shin),홍철호(Chol-Ho Hong),박경우(Kyoungwoo Park) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
In DTP(digital textile printing) system, the selection of inkjet printhead is one of the core technologies. The printing quality such as the volume and velocity of droplets as well as the formation of satellite droplets is known to be closely related to the injection behaviors of the ink droplet. In the present work, we investigate the droplet behavior of micro-inkjet for a shear-mode piezoelectric(PZT) actuators numerically. The transient three-dimensional conservation equations of mass and momentum are solved by the computational fluid dynamics(CFD). The continuous surface force(CFS) model is used in order to predict the effect of surface tension force in the free surface flow. The volume-of-fluid(VOF) method with the piecewise linear interface construction(PLIC) scheme is employed for tracking the interfacial movement and reconstructing the interface between liquids and gas (ink and air). This study predict the droplet formation characteristics for the given properties of ink and geometry of printhead and the effects of thermal properties of ink and nozzle shape on the droplet quality are also investigated.
김길동(Gildong Kim),이한민(Hanmin Lee),이장무(Changmu Lee),오세찬(Sehchan Oh),정의진(Euijin Joung) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.5월
As a drive system for next generation train, we have been making research and development of a direct drive traction motor system without the conventional reduction gear. This traction motor is expected to have many advantages such as low noise, reduced maintenance, and energy saving. Due to the demand for high-output motors in the limited space between the wheels, open-ventilating traction motors with gear box have been widely used for many years. However, a conventional open-ventilating traction motor is necessary periodical disassembly to remove the accumulated dust from open-air ventilation. Reducing this burden, as well as increasing energy efficiency and reducing noise, would benefit the next generation of traction motors. To address these needs, KRRI have been developing a fully enclosed type direct drive motor(DDM) with high-efficiency permanent magnet for the next generation train.
김길동(Kim Gildong),이한민(Lee Hanmin) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-
The control method of programmable dynamometer for overall test of machine is to load the reference torque which is computed from torque transducer into motor under test. But the torque information detected from torque transducer have a lot of noise when the load torque of moter is a small quantity or changing. Thus, torque transducer must have a low pass filter to detect a definite torque information. But The torque delay generated by filter with torque transducer occur a torque trouble for moter torque of programmable dynamometer. Therefore, this kind of system could not perform dynamic and nonlinear load. In this paper, the control method using the load torque observer without a measure for torque transducer is proposed. The proposed system improved the problem of the torque measuring delay with torque transducer, and the load torque is estimated by the minimal order state observer based on the torque component of the vector control induction moter. Therefore, the torque controller is not affected by a load torque disturbance.
에너지저장시스템의 전기철도적용에 의한 온실가스 저감에 관한 연구
김길동(Gildong Kim),이한민(Hanmin Lee) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.4
The ESS(energy storage system, here after) is considered for saving energy and cutting Co₂. Therefore, this paper presents effects of Co₂-cut obtained by applying the ESS in Korean urban transit system.
전동차 회생에너지 활용을 위한 저장시스템 적용기술 연구
김길동(Gildong Kim),이한민(Hammin Lee),오세찬(Sechan Oh),이장무(Changmu Lee) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.4
There are operated the six thousand train in the interior of a country. 95% of them are possible usage of resuscitation. Especially, Among them VVVF-Inverter vehicle has a merit of the highest recycle rate, but we don't use a apt recycled energy. Although the existing recycle energy used inverter method supply with electric power, it is decided in accordance with the state of sources. So efficiency of recycled electric power is of poor quality and catenary-voltage-fluctuation be generate because of recycled electric power, and it is able to affect system of safety train service. We'll research the method of supply according to wire condition after storing recycle energy made during train's stopping relation to Advanced EMU Research. Those methods are divided SMES, Fly-Wheel and Supercapacitor, and Considering the both economical efficiency and system application, we'll develop recycle energy storage system suitable our country condition.