TY - JOUR

T1 - Atomistic simulation of micro-scale adiabatic piston problem

AU - Sengil, Nevsan

AU - Oguz Edis, Firat

PY - 2009/10/16

Y1 - 2009/10/16

N2 - Purpose- The purpose of this paper is to demonstrate the utilization of the direct simulation Monte Carlo (DSMC) method for moving-boundary/deforming-domain micro-scale gas flow problems. Furthermore, a hydrodynamic model, proposed in the literature, is used to compare its results with those obtained using the DSMC method.Design/methodology/approach- A micro-scale adiabatic piston problem is analyzed using a parallel DSMC implementation for deforming domains. Initially, pressures at both sides of the piston wall are different. Consequently, frictionless piston moves toward low-pressure compartment, keeps oscillating from one side to the other. Eventually, the piston reaches the “Mechanical equilibrium” state. Although the temperatures are different, pressures are equal at this state. The unsteady problem is analyzed until it reaches this state. Three test cases, all with the same initial conditions but different piston masses are analyzed. The time variation of the piston position, conditions in the compartments separated by the piston, are presented and compared with the results obtained from a hydrodynamic model proposed in the literature.Findings- The results show that the DSMC and hydrodynamic results agree for the case where the piston mass is much larger than the mass of the gas inside the cylinder. But for other two cases, where the piston mass is smaller, piston motion, and conditions in the compartments separated by the piston differ for the two methods. This is attributed to the linear velocity distribution assumption of the hydrodynamic model. The DSMC results demonstrate that this assumption is not valid for cases where the piston mass is equal or less than the mass of the gas inside the cylinder.Originality/value- Implementation of the DSMC method for problems with deforming domain is presented and a limitation for applicability of hydrodynamic model for these problems is shown.

AB - Purpose- The purpose of this paper is to demonstrate the utilization of the direct simulation Monte Carlo (DSMC) method for moving-boundary/deforming-domain micro-scale gas flow problems. Furthermore, a hydrodynamic model, proposed in the literature, is used to compare its results with those obtained using the DSMC method.Design/methodology/approach- A micro-scale adiabatic piston problem is analyzed using a parallel DSMC implementation for deforming domains. Initially, pressures at both sides of the piston wall are different. Consequently, frictionless piston moves toward low-pressure compartment, keeps oscillating from one side to the other. Eventually, the piston reaches the “Mechanical equilibrium” state. Although the temperatures are different, pressures are equal at this state. The unsteady problem is analyzed until it reaches this state. Three test cases, all with the same initial conditions but different piston masses are analyzed. The time variation of the piston position, conditions in the compartments separated by the piston, are presented and compared with the results obtained from a hydrodynamic model proposed in the literature.Findings- The results show that the DSMC and hydrodynamic results agree for the case where the piston mass is much larger than the mass of the gas inside the cylinder. But for other two cases, where the piston mass is smaller, piston motion, and conditions in the compartments separated by the piston differ for the two methods. This is attributed to the linear velocity distribution assumption of the hydrodynamic model. The DSMC results demonstrate that this assumption is not valid for cases where the piston mass is equal or less than the mass of the gas inside the cylinder.Originality/value- Implementation of the DSMC method for problems with deforming domain is presented and a limitation for applicability of hydrodynamic model for these problems is shown.

KW - Deformation

KW - Fluidics

KW - Gas flow

KW - Monte Carlo methods

UR - http://www.scopus.com/inward/record.url?scp=73849097905&partnerID=8YFLogxK

U2 - 10.1108/00022660910997793

DO - 10.1108/00022660910997793

M3 - Article

AN - SCOPUS:73849097905

SN - 0002-2667

VL - 81

SP - 499

EP - 507

JO - Aircraft Engineering and Aerospace Technology

JF - Aircraft Engineering and Aerospace Technology

IS - 6

ER -