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이선엽(Sun Youb Lee),하콩투(Cong-Tu Ha),이재화(Jae Hwa Lee) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
In a cooling system for thermal management of miniaturized and high-integrated electronic devices, the bubble with a phase change transports under the influence of the wall. However, although it is important to consider the influence of the wall due to the difference in flow patterns caused by the influence of the wall, most previous studies have not been studied the effect of the wall on a condensing bubble. In the present study, we perform numerical simulations for tube diameters (D<SUB>tube</SUB>) of 1.2≤D<SUB>tube</SUB>/D<SUB>0</SUB>≤3.0 based on the initial bubble diameter (D<SUB>0</SUB>) to investigate the effect of tube diameter on single bubble condensation in the subcooled flow. It is shown that as Dtube decreases, the condensation rate decreases due to the influence of the wall and the bubble moves to a higher position. Moreover, it has been found that at a small D<SUB>tube</SUB>, the reduction of heat and mass transfer is caused by the recirculation flow that occurs in the narrow gap between the bubble side and the tube wall.
직렬 배열된 두 기포의 bursting jet에 대한 수치적 연구
이창걸(Chang Geol Lee),이선엽(Sun Youb Lee),Cong-Tu Ha,이재화(Jae Hwa Lee) 한국가시화정보학회 2020 한국가시화정보학회지 Vol.18 No.3
When a bubble reaches a free surface, a bursting of the bubble produces a high speed jet. Despite its practical importance, significant effort has been devoted to investigate a bursting jet by a single bubble near a free surface. In the present study, we perform numerical simulations of bubbles in a tandem arrangement at Bo=0.05. The configuration of the tandem bubbles is systematically varied by changing a radius of a following bubble (RF) and the gap distance between two bubbles (L). Compared to a single bubble case, we show that the bursting bubble in the tandem arrangement accelerates, and the jet velocity increases. Moreover, we find that a critical gap distance at which the jet velocity unexpectedly changes exists in the tandem case.