Effect of pressure, membrane thickness, and placement of control volumes on the flux of methane through thin silicalite membranes: A dual control volume grand canonical molecular dynamics study

2001 ◽  
Vol 114 (16) ◽  
pp. 7174-7181 ◽  
Author(s):  
Marcus G. Martin ◽  
Aidan P. Thompson ◽  
Tina M. Nenoff
Keyword(s):  
Molecular Dynamics ◽  
Control Volume ◽  
Membrane Thickness ◽  
Dual Control ◽  
Effect Of Pressure ◽  
Control Volumes ◽  
Grand Canonical

Gradient-Driven Diffusion Using Dual Control Volume Grand Canonical Molecular Dynamics (DCV-GCMD)

1995 ◽  
Vol 408 ◽  
Author(s):  
Frank Van Swol ◽  
Grant S. Heffelfinger
Keyword(s):  
Molecular Dynamics ◽  
Chemical Potential ◽  
Control Volume ◽  
Simulation Method ◽  
Steady State Mode ◽  
Transient Phenomena ◽  
Insertion And Deletion ◽  
Separate Control ◽  
Control Volumes ◽  
Grand Canonical

AbstractRecently we developed a new nonequilibrium molecular simulation method [1] that allows the direct study of interdiffusion in multicomponent mixtures. The method combines stochastic insertion and deletion moves characteristic of grand canonical (GC) simulations with molecular dynamics (MD) to control the chemical potential μi of a species i. Restricting the insertions and deletions to two separate control volumes (CV's) one can apply different μ's in distinct locations, and thus create chemical potential gradients. DCV-GCMD can be used to study transient phenomena such as the filling of micropores or used in steady-state mode to determine the diffusion coefficients in multicomponent fluid mixtures. We report on the effects of molecular interactions and demonstrate how in a sufficiently nonideal ternary mixture this can lead to up-hill or reverse diffusion. In addition we introduce a novel extension of DCV-GCMD that is specifically designed for the study of gradient-driven diffusion of molecules that are simply too large to be inserted and deleted.

Molecular Dynamics Computer Simulations of Diffusion in Porous Silicates

1994 ◽  
Vol 366 ◽  
Author(s):  
Grant S. Heffelfinger ◽  
Phillip I. Pohl ◽  
Laura J. D. Frink
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Chemical Potential ◽  
Control Volume ◽  
Dual Control ◽  
Cylindrical Pore ◽  
Knudsen Effect ◽  
State Pressure ◽  
Molecular Sieving ◽  
Grand Canonical

ABSTRACTIn this work a newly developed dual control volume grand canonical molecular dynamics technique simulates the diffusion of gas in a cylindrical pore. This allows spatial variation of chemical potential and hence an accurate simulation of steady state pressure driven diffusion. The molecular sieving nature of imicroporous imogolite models and the Knudsen effect are discussed and compared with experimental data.

Preliminary Study of the Effect of Pressure on Asphaltene Disassociation by Molecular Dynamics

2004 ◽  
Vol 22 (7-8) ◽  
pp. 927-942 ◽  
Author(s):  
J. H. Pacheco-Sánchez ◽  
I. P. Zaragoza ◽  
J. M. Martínez-Magadán
Keyword(s):  
Molecular Dynamics ◽  
Effect Of Pressure ◽  
Preliminary Study

Defining the Thermodynamic Efficiency in a Wave Rotor

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Shining Chan ◽  
Huoxing Liu ◽  
Fei Xing
Keyword(s):  
Gas Turbine ◽  
Control Volume ◽  
Thermodynamic Efficiency ◽  
Wave Rotor ◽  
Wave Rotors ◽  
Compression And Expansion ◽  
Efficiency Estimation ◽  
Parametric Analyses ◽  
Control Volumes ◽  
Thermodynamic Processes

A wave rotor enhances the performance of a gas turbine with its internal compression and expansion, yet the thermodynamic efficiency estimation has been troubling because the efficiency definition is unclear. This paper put forward three new thermodynamic efficiency definitions to overcome the trouble: the adiabatic efficiency, the weighted-pressure mixed efficiency, and the pressure pre-equilibrated efficiency. They were all derived from multistream control volumes. As a consequence, they could correct the efficiency values and make the values for compression and expansion independent. Moreover, the latter two incorporated new models of pre-equilibration inside a control volume, and modified the hypothetical “ideal” thermodynamic processes. Parametric analyses based on practical wave rotor data demonstrated that the trends of those efficiency values reflected the energy losses in wave rotors. Essentially, different thermodynamic efficiency definitions indicated different ideal thermal cycle that an optimal wave rotor can provide for a gas turbine, and they were recommended to application based on that essence.

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