• 한국전산유체공학회지
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• 제13권3호
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• pp.8-13
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• 2008

We present a numerical simulation technique and some preliminary results of the impact and spreading of a droplet containing particles on the solid substrate in 2D. We used the 2nd-order Adams-Bashforth / Crank-Nicholson method to solve the Navier-Stokes equation and employed the level-set method with the continuous surface stress for description of droplet spreading with interfacial tension. The impact velocity has been generated by the instantaneous gravity. The distributed Lagrangian-multipliers method has been combined for the implicit treatment of rigid particles and the discontinuous Galerkin method has been used for the stabilization of the interface advection equation. We investigated the droplet spreading by the inertial force and discussed effects of the presence of particles on the spreading behavior using an example problem. We observed reduced oscillation and spread for the particulate droplet.

• 대한금속재료학회지
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• 제46권8호
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• pp.506-515
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• 2008

Recently, it is exceedingly required to produce metal powders with tailored shape and phase altogether in order to fabricate high performance functional parts such as magnetic core or electro-magnetic noise suppressor for high frequency usage. Therefore, the collision phenomena of in-flight droplets against chamber wall or neighboring in-flight droplets each other is investigated by a computational method in order to get useful information about how to design the atomizing system and how to tailor process parameters not to make irregular-shaped powders during gas atomization process. As a results, smaller powders, lower melt temperature are known to be favorable for droplets not to collide against chamber wall. In additions, powders of narrower size distribution range, lower droplet generation rate, lower melt temperature, lower gas velocity are desirable to prevent droplet-collisions against neighboring in-flight droplets.

• 한국추진공학회지
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• 제10권3호
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• pp.9-17
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• 2006

본 연구는 케로신-LOX를 추진제로 하는 액체로켓엔진용 스월 동축형 인젝터의 리세스 길이에 따른 분무특성 파악을 목표로 하였다. 리세스 길이에 따른 두 추진제의 내부충돌현상에 의한 ripple의 형성과 감쇠가 인젝터 외부의 분무안정성에 영향을 미치므로 분무특성과 큰 연관성을 가진다. 또한, 리세스 길이가 증가함에 따라 평균액적크기는 증가하였으며, 혼합효율은 증가하다가 최대값에 도달한 후 다시 감소하는 경향성을 보였다.