• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.751-756
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• 2001

An experimental model of the advanced mixing control in the parallel supersonic-subsonic mixing jet (M$_1$=1.78 and M$_2$=0.30) is numerically simulated. An oscillating wall boundary condition is used as the modeling of a wall cavity for mixing enhancement. The obtained pitot pressure distributions along cross sections at the developing region of the turbulent jets are validated from the good agreement with equivalent experimental data. The similarity solution of dimensional analysis also coincides with this numerical result at the self-similar region sufficiently far from the jet exit.

• 한국막학회:학술대회논문집
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• 한국막학회 1995년도 추계 총회 및 학술발표회
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• pp.5-9
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• 1995

In the dry-jet-wet-spinning process of a hollow fiber membrane, the polymer solution is pumped into a coaxial tube, jet spinneret. The threadline emerging from the spinneret is stabilized by an internal coagulating medium(liquid or gas) as it emerges from the jet orifice. The nascent hollow thread is further stabilized in a quench bath as shown in Fig. 1. In this scheme, three mechanism of formatiota(temperature gradient, solvent evaporation, and solvent-nonsotvent exchange) can be combined. The changes which promote stabilization often play a dominant role in determining the ultimate fiber wall structure as well. Hence, in pratice, hollow fiber stabilization and development of membrane structure are commonly inseparable. However, fiber dimension(the inside diameter and wall thickness of the hollow fiber) is mainly a rheological problem and is determined by dope pumping rate, spinneret diatance from the coagulation bath, inner coagulant flow rate, and fiber draw-rate. Besides rheological phenomena play a prominent part in the final properties of the hollow fiber.

• International Journal of Advanced Culture Technology
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• 제3권2호
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• pp.171-178
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• 2015

In this work, mixing processes of hot and cold fluids of three different jet types are predicted by large-eddy simulation (LES) on FLUENT platform. Temperature at different positions of internal wall and mixing conditions of T-junctions at different times are obtained, then the simulated normalized mean and root-mean square (RMS) temperature, temperature contour and velocity vector of every case are compared. The results indicate that, the mixing regions in the tee junction is related to the jet type, and temperature fluctuations on the pipe wall in the type of the deflecting jet is the least.

• 한국화재소방학회논문지
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• 제18권4호
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• pp.27-34
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• 2004

CO₂소화장치의 CO₂노즐과 방호공간 내 벽 사이의 거리변화에 따른 유동 및 CO₂질량전달효과를 분석하기 위하여 CO₂노즐과 후측 벽 사이의 거리를 변화시키면서 전산모이실험을 3차원 비정상상태로 수행하였다. 유동장과 CO₂소화제 농도장을 계산하였다. CO₂노즐과 후측 벽 사이의 거리 증가에 따라 다른 재 순환 유동형태와 벽면제트기류가 형성되었다. CO₂ 소화제 질량전달은 모든 경우에서 각 벽으로부터 방호공간의 중앙으로 일어나지만 CO₂소화제 노즐의 전 후 영역의 CO₂질량분율은 CO₂노즐과 벽 사이의 거리 증가에 따라 높거나 낮게 나타났다.

• International Journal of Automotive Technology
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• 제3권1호
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• pp.9-16
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• 2002

In plasma jet ignition, combustion enhancement effects occur toward the plasma jet issuing direction. Therefore, when the igniter is attached at the center of a cylindrically shaped combustion chamber, plasma jet should issue toward the round combustion chamber wall. The plasma jet igniter that had an annular circular orifice has been developed. The purpose of this study is to elucidate the relationship between the newly developed plasma Jet igniter configuration and combustion enhancement effects. In this newly developed plasma Jet igniter, flame front wrinkle appears on the flame front and flame propagates rapidly. Plasma Jet influences on the flame propagation far long period when the plasma jet igniter has issuing angle 90 degrees and large cavity volume, because the plasma jet only lasts several ms. However, in the early stage of combustion, flame front area of issuing angle 45 degrees is larger than that of 90 degrees, because the initial flame kernel is formed by the plasma jet.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.100-109
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• 2006

구리합금을 연소실 내벽으로 사용하고 탄화수소계 연료를 추진제로 사용하는 재생냉각 연소기에서 냉각채널 벽면온도가 상승함에 따라 냉각채널에 반응물이 침착되는 코킹현상이 일어난다. 이러한 현상은 냉각채널을 흐르는 연료에 의한 냉각효과를 감소시키게 되고, 높은 열유속으로 운영되는 연소기 내부벽면을 과열시켜 손상에 이르게 한다. 본 논문에서는 구성된 전기가열장치에 대해 소개하고 연소실 재질로 사용되고 있는 구리합금과 추진제로 사용되는 탄화수소계 연료 Jet A-1에 대해 가열시험 결과를 제시한다. 시험결과에 따라 각 조건에서의 구리합금과 Jet A-1의 적합성을 평가하였다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.53-54
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• 2006

Experimental analyses on the Hydroelastic Flow-Structure Interactions on pulsed impinged jet is measured with the FSIMS(Flow-Structure Interaction Measurement System. The nozzle diameter is D=15mm and two major experiments have been carried out for the cases of the distance between the nozzle tip to the elastic wall is 6.0. The pulsed jets were controlled by a solenoid valve and were impinged onto an elastic plate (material: silicon, diameter: 350mm, thickness: 0.5mm, hardness: 15). The Reynolds numbers were 20,000 and 24,000 when the jets were impinged with the volume velocities. The results showed that the elastic plate moved slightly to the opposite direction of the jet direction at the time of valve opening. It has been shown that the vortices travelling over the surface of the wall made the elastic wall distorted locally due to a vector forces between rotating forces of the vortex and a newly-incoming flow.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.241-242
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• 2013

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1845-1850
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• 2004

The laminar impinging jet flow fields were investigated with or without magnetic fields. The transient phenomenon from steady to unsteady flow was founded at specific Reynolds number ranges. In unsteady flow region, the magnetic fields make flow stable. So the characteristics of fluid flow at impingement wall are changed

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1447-1451
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• 2004

The laminar impinging jet thermal fields were investigated with or without magnetic fields. The transient phenomenon from steady to unsteady flow was founded at specific Reynolds number ranges. In unsteady flow region, the magnetic fields make flow stable. So the characteristics of heat transfer at impingement wall are changed