Critical Review of Fluid Flow Physics at Micro‐ to Nano‐scale Porous Media Applications in the Energy Sector

Abstract

While there is a consensus in the literature that embracing nanodevices and nanomaterials helps in improving the efficiency and performance, the reason for the better performance is mostly subscribed to the nanosized material/structure of the system without sufficiently acknowledging the role of fluid flow mechanisms in these systems. This is evident from the literature review of fluid flow modeling in various energy-related applications, which reveals that the fundamental understanding of fluid transport at micro- and nanoscale is not adequately adapted in models. Incomplete or insufficient physics for the fluid flow can lead to untapped potential of these applications that can be used to increase their performance. This paper reviews the current state of research for the physics of gas and liquid flow at micro- and nanoscale and identified critical gaps to improve fluid flow modeling in four different applications related to the energy sector. The review for gas flow focuses on fundamentals of gas flow at rarefied conditions, the velocity slip, and temperature jump conditions. The review for liquid flow provides fundamental flow regimes of liquid flow, and liquid slip models as a function of key modeling parameters. The four porous media applications from energy sector considered in this review are (i) electrokinetic energy conversion devices, (ii) membrane-based water desalination through reverse osmosis, (iii) shale reservoirs, and (iv) hydrogen storage, respectively. Review of fluid flow modeling literature from these applications reveals that further improvements can be made by (i) modeling slip length as a function of key parameters, (ii) coupling the dependency of wettability and slip, (iii) using a reservoir-on-chip approach that can enable capturing the subcontinuum effects contributing to fluid flow in shale reservoirs, and (iv) including Knudsen diffusion and slip in the governing equations of hydrogen gas storage.

Gas Hydrate Combustion in Five Method of Combustion Organization

“…In addition, the porosity inside the particles (granules) is also realized during dissociation. Regularities of gas flow through a porous medium are considered in [ 20 ]. The influence of diffusion and heat fluxes, as well as the size of granules, on the dissociation rate is given in [ 21 , 22 ].…”

Spontaneous imbibition in shale: A review of recent advances

“…To achieve this, several million gallons of fracturing liquid is injected at high pressure into shale plays (Palisch et al, 2010;Soliman et al, 2012) to create hydraulic fractures and proppants are mixed with the liquid to keep the fractures from closing The injected fracturing liquid triggers a series of liquid-shale interaction processes that are affected by the operational conditions such as injection, flowback, shut-in, and production; spontaneous imbibition is one of such key liquid-shale interactions. Although spontaneous imbibition, in other words liquid uptake by the porous medium without an enforced pressure, is a universal phenomenon in porous media and its diverse applications (Singh and Myong, 2018), its occurrence in shale rocks is understood to a relatively lesser extent because of complex pore structure and heterogeneous properties. Production data shows that, generally for high production wells only 6%-10% of injected water can be recovered during the fracturing process (Vandecasteele et al, 2015) and up to 48% in the entire production history (Nicot et al, 2012;Roychaudhuri et al, 2013).…”

Nanoscale Flow Choking at the Zero Slip Length: Universal Benchmark Data for In Silico Experiments

“…Cooper et al 19 reported that in vitro data well matched with the predicted results using the hydrodynamic Navier Stokes method with the first-order slip condition for the range of average pore diameters from 169-220 nm. Singh and Myong 36 reported that neither continuum models nor free-molecular models could be invoked for fluid flow cases when the Knudsen number falls in the intermediate range between the continuum (Kn < 0.01) and free-molecular flow regimes (Kn>10). When the Knudsen number becomes large (Kn > 0.01), the conventional assumptions of no-slip boundary condition, thermodynamic equilibrium, and linear stress-strain relationship fail.…”