Dongari, Nishanth and Zhang, Yonghao and Reese, Jason (2010) Molecular dynamics studies of anomalous transport in rarefied gas flows. In: 2nd European Conference on Microfluidics, 2010-12-08 - 2010-12-10.
Zhang_YH_Reese_JM_Pure_Molecular_dynamics_studies_of_anomalous_transport_in_rarefied_gases_Dec_2010.pdf - Preprint
We investigate the thermodynamically non-equilibrium gas dynamics by measuring molecular free path distribution functions, inter-molecular collision rates and wall dependent mean free path (MFP) profiles using the molecular dynamics (MD) method. The simulations cover a wide range of fluid densities for single-wall case, parallel walls cases and a cube with all periodic walls. The simulations are validated by deducing the theoretical unconfined MFP values at standardpressure and temperature conditions. The free path MD measurements of individual molecules convey that conventional exponential distribution function is not valid under rarefied conditions and molecules follow L´evy type flights, irrespective of the presence of a wall. MFP profile measurements for confined planar surfaces in the transition flow regime show sharp gradients close to the wall, while theoretical models predict shallower gradients. As gas transport properties can be related to the MFP through kinetic theory, our MD data may help to modify the constitutive relationships, which may then be fed into the Navier-Stokes equations for better effective modeling of micro gas flows in the transition flow regime.
|Item type:||Conference or Workshop Item (Paper)|
|Notes:||Published on CD-ROM|
|Keywords:||rarefied gas flows, free path distribution, L´evy flights, mean free path , molecular dynamics, Mechanical engineering and machinery, Mechanical Engineering, Atomic and Molecular Physics, and Optics|
|Subjects:||Technology > Mechanical engineering and machinery|
|Department:||Faculty of Engineering > Mechanical and Aerospace Engineering|
|Depositing user:||Pure Administrator|
|Date Deposited:||13 Jul 2011 09:07|
|Last modified:||06 Mar 2017 14:18|