Analytical solution of micro-/nanoscale convective liquid flows in tubes and slits

Abstract

with confinement sizes for no-dissipation cases. In case of non-negligible heat dissipation, viscous heating dominated the Nu value by enhancing the heating while decreasing the heat removal in cooling cases. Implementation of proposed procedure on a micro-channel convection problem from a micro-fluidics application showed the dominant effect of the model defining the slip and jump relationship. Direct use of kinetic gas theory resulted in an increase of Nu by an increase in non-equilibrium, while models developed from published liquid slip and jump values produced an opposite behavior.

Slip Effects on Ionic Current of Viscoelectric Electroviscous Flows through Different Length Nanofluidic Channels

“…Overall, velocity slip on the wall significantly increased the ionic transport even at this moderate slip length value. 16,46 Without viscoelectric effects, ionic current continues to increase as the salt concentration increases, similar to the noslip condition. Here, velocity slip decreases with an increase in salt which also results in a decrease of electroviscous effects, such that corresponding decreasing and increasing effects on ionic current remained in balance with each other.…”

“…76,77 We also used eq 8 with L s,0 = 5 nm, which is an average value for silica/water interfaces. 46,78 The coupled behavior of the local ionic concentration in the electrolyte solution and the surface dissociation/association reactions creates the surface charge. This spontaneous phenomenon is commonly simulated by charge regulation models 26,79−85 in the literature.…”

“…10,35,40−45 Interface slip is defined as a function of two parameters: (i) slip length and (ii) velocity gradient at the interface. 46 First, slip length is proven to be a material property of the solid/liquid couple by many researchers. 46−51 Multiple studies relate the slip length to surface wetting and describe its variation by contact angle.…”

“…Multiple numerical and theoretical studies explained that the hydrodynamic slip enhances the ion transport so the efficiency of related applications such as electrokinetic energy conversion. , Researchers also presented increased conduction current opposite to ionic current direction revealing itself as increased apparent viscosity (electroviscosity) ,− in case of slip, but overall flow rate and ionic current were found to still increase. For a liquid flow, the partial slip boundary condition was described by Navier in 1823 and later acknowledged and validated by numerous researchers showing that the continuum solutions with Navier-slip condition yield accurate flow calculations for confinements as small as 3–4 nm. ,,− Interface slip is defined as a function of two parameters: (i) slip length and (ii) velocity gradient at the interface . First, slip length is proven to be a material property of the solid/liquid couple by many researchers. − Multiple studies relate the slip length to surface wetting and describe its variation by contact angle. , Surface electric condition is also found affecting the slip length, ,,, but it actually develops at high surface charge values above the natural surface charging range.…”

“…For a liquid flow, the partial slip boundary condition was described by Navier in 1823 and later acknowledged and validated by numerous researchers showing that the continuum solutions with Navier-slip condition yield accurate flow calculations for confinements as small as 3–4 nm. ,,− Interface slip is defined as a function of two parameters: (i) slip length and (ii) velocity gradient at the interface . First, slip length is proven to be a material property of the solid/liquid couple by many researchers. − Multiple studies relate the slip length to surface wetting and describe its variation by contact angle. , Surface electric condition is also found affecting the slip length, ,,, but it actually develops at high surface charge values above the natural surface charging range. Second, velocity slip also depends on the near surface hydrodynamics that earlier mentioned electroviscosity and viscoelectic effects inside the EDL are expected to strongly alter, e.g., the boundary slip.…”