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Ji Hwan Lim

Bio: Ji Hwan Lim is an academic researcher from Yonsei University. The author has contributed to research in topics: Mach number & Shock (fluid dynamics). The author has an hindex of 1, co-authored 2 publications receiving 35 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the starting transient and plume blowback at diffuser breakdown of a straight cylindrical supersonic exhaust diffuser with no externally supplied secondary flow are numerically investigated.

36 citations


Cited by
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Journal ArticleDOI
01 Nov 2012-Energy
TL;DR: In this paper, a numerical method has been implemented to evaluate the formation of droplets due to condensation in a convergent-divergent nozzle and the verified numerical scheme has been applied to internal flow of the thermo-compressor.

32 citations

Journal ArticleDOI
15 Oct 2018-Energy
TL;DR: In this article, a low area ratio rectangular supersonic gaseous ejector is subjected to parametric evaluation to calculate the performance parameters like stagnation pressure ratio, compression ratio, entrainment ratio and the mixing parameter known as non-mixed length.

28 citations

Journal ArticleDOI
TL;DR: In this paper, an experimental investigation was conducted to study the Reynolds number influence on dual-bell transition behavior for tests inside a high-altitude simulation chamber, where the authors found that the width of the inflection region decreases with an increase in the nozzle Reynolds number.
Abstract: An experimental investigation was conducted to study the Reynolds number influence on dual-bell transition behavior for tests inside a high-altitude simulation chamber. For the range of nozzle supply pressures tested, the nozzle Reynolds number is seen to gradually decrease from a relatively high value (of the order of 107 for tests in sea-level atmospheric conditions) toward the transitional range (lower side of 106 for tests inside the high-altitude chamber). This influences the width of the inflection region, which is seen to decrease with an increase in nozzle Reynolds number. Because of the smaller negative pressure gradient experienced during sneak transition with a decrease in nozzle Reynolds number, the separation point is seen to move into the region of wall inflection much earlier and tends to stay in the region of wall inflection for a relatively longer time. Although the time duration of final transition remains more or less constant for different nozzle supply pressure values, the time durati...

24 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of essential performance parameters on the starting transient of a straight cylindrical supersonic exhaust diffuser (SED) are numerically investigated in terms of SED length and pre-evacuation configuration.

24 citations

Journal ArticleDOI
01 Jul 2010
TL;DR: In this article, the authors analyzed the transient flow through the vacuum ejector system with the help of a computational fluid dynamics method and showed that the one and only condition in which a continuous mass entrainment can be possible in such types of ejectors is the generation of a recirculation zone near the primary nozzle exit.
Abstract: The objective of the present study is to analyse the transient flow through the vacuum ejector system with the help of a computational fluid dynamics method. An attempt is made to investigate the interesting and conflicting phenomenon of the continuous entrainment into the primary stream with limited mass supply from the secondary chamber. The results obtained show that the one and only condition in which a continuous mass entrainment can be possible in such types of ejectors is the generation of a recirculation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium of pressure at the onset of the recirculation zone. A steady flow assumption in such ejector systems is valid only after the dynamic equilibrium state.

22 citations