We study explosive gasliquid flows caused by rapid depressurization using a molecular dynamics model of Lennard-Jones particle systems. A unique feature of our model is that it consists of two types of particles: liquid particles, which tend to form liquid droplets, and gas particles, which remain supercritical gaseous states under the depressurization realized by simulations. The system has a pipe-like structure similar to the model of a shock tube. We observed physical quantities and flow regimes in systems with various combinations of initial particle number densities and initial temperatures. It is observed that a physical quantity Q, such as pressure, at position z measured along a pipe-like system at time t follows a scaling relation Q(z,t)=Q(zt) with a scaling function Q(ζ). A similar scaling relation holds for time evolution of flow regimes in a system. These scaling relations lead to a regime map of explosive flows in parameter spaces of local physical quantities. The validity of the scaling relations of physical quantities means that physics of equilibrium systems, such as an equation of state, is applicable to explosive flows in our simulations, though the explosive flows involve highly nonequilibrium processes. In other words, if the breaking of the scaling relations is observed, it means that the explosive flows cannot be fully described by physics of equilibrium systems. We show the possibility of breaking of the scaling relations and discuss its implications in the last section. © 2011 Elsevier B.V. All rights reserved.
|Original language||English (US)|
|Number of pages||16|
|Journal||Physica A: Statistical Mechanics and its Applications|
|State||Published - Feb 2012|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUK-I1-005-04
Acknowledgements: This work has been partly supported by Award No. KUK-I1-005-04 granted by King Abdullah University of Science and Technology (KAUST) and Grant-in-Aid for Young Scientists (B) No. 19740238 from the Ministry of Education, Culture, Sports, Science, and Technology. A part of the numerical simulations in this paper was carried out by the use of the Plasma Simulator at the National Institute for Fusion Science under the support of the NIFS Collaboration Research programs (NIFS10KTBS006).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.