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statistical-fluctuations
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DSMC simulation of heat transfer in subsonic rarefied gas flows through micro/nanochannels imposing a constant inflow/wall temperature difference
, Article 41st AIAA Fluid Dynamics Conference and Exhibit ; 2011 ; 9781600869471 (ISBN) ; Karchani, A ; Akhlaghi, H ; Mosayebi, G ; Schneider, G. E ; Sharif University of Technology
Abstract
We use the direct simulation Monte Carlo (DSMC) method and investigate the subsonic rarefied gas flow through micro/nanochannels, imposing a constant pressure ratio and a constant temperature difference between the inflow and wall temperature. We further study the heat transfer characteristics of subsonic nitrogen gas flow under this imposed temperature difference. We show that, specifying a higher temperature magnitude would lead to more rarefactions even imposing a fixed temperature difference. This consequently results in a higher wall heat flux rate for a fixed inflow-wall temperature difference. Our investigating shows that the number of simulated particles need to increase suitably if...
Rarefaction effects on gas mixing in micro- and nanoscales
, Article ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2016, 4 January 2016 through 6 January 2016 ; Volume 1 , 2016 ; 9780791849651 (ISBN) ; Sabouri, M ; Heat Transfer Division ; Sharif University of Technology
American Society of Mechanical Engineers
2016
Abstract
We present the rarefaction effects on diffusive mass transport in micro- and nanoscales using the results of direct simulation Monte Carlo DSMC method. Unlike the previous investigations, the momentum and heat contributions are eliminated from the computations via uniform velocity, pressure, and temperature field considerations. The effects of global Knudsen number on the diffusion phenomenon are studied for the same Peclet number and a unique mixer shape. The results indicate that there is considerable weakening in diffusion mechanism for high Knudsen number cases. As a result, the non-dimensional diffusive mass fluxes would decrease and the non-dimensional mixing length would increase as...
Extending a hybrid continuum-molecular simulation method to solve the micro/nanoscale gas mixing problems
, Article ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting, FEDSM 2018, 15 July 2018 through 20 July 2018 ; Volume 3 , 2018 ; 08888116 (ISSN); 9780791851579 (ISBN) ; Darbandi, M ; Schneider, G. E ; Fluids Engineering Division ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2018
Abstract
Despite vast efforts in developing hybrid continuum-molecular methods, there has been no specific work focused on the gas mixture flow simulations including the mixing and/or separation of species. In present study, we extend a hybrid method to analyze such phenomena suitably and study the gas mixing problems in micro/nano length scales reliably. The results of current hybrid simulations are compared against the results of full-molecular simulations to evaluate the physical accuracy of developed hybrid method. The effect of continuum breakdown criterion is investigated to find out the achieved accuracy of developed hybrid simulation method from different perspectives. The current results...