Spontaneous Imbibition Into Hele-Shaw Cells Under Temperature Differences

Volume 1 ◽  
2004 ◽  
Author(s):  
M. Sa´nchez ◽  
A. Medina ◽  
F. J. Higuera ◽  
J. L. Montanes
Keyword(s):  
Surface Tension ◽  
Temperature Gradient ◽  
Temperature Dependence ◽  
Lubrication Theory ◽  
Spontaneous Imbibition ◽  
Longitudinal Temperature Gradient ◽  
Longitudinal Temperature

In this work has been analyzed theoretically and experimentally imbibition under the influence of a longitudinal temperature gradient. Imbibition into vertical and circular cells was analyzed using the lubrication theory. The temperature-dependence of viscosity and surface tension were included in the lubrication equations. In both cases was found that theory describes very well the experimental trends. Moreover, experiments using glycerol show a notable acceleration of the fronts under positive gradients.

scholarly journals Heat and Mass Transport in Carbon Nantubes

2010 ◽  
Author(s):  
Junichiro Shiomi ◽  
Carl Fredrik Carlborg ◽  
Shigeo Maruyama
Keyword(s):  
Molecular Dynamics ◽  
Temperature Gradient ◽  
Mass Transport ◽  
Small Diameter ◽  
Elastic Interaction ◽  
Heat And Mass Transport ◽  
Longitudinal Temperature Gradient ◽  
Longitudinal Temperature ◽  
Argon Matrices ◽  
Dynamics Simulations

We have investigated heat and mass transport in single-walled carbon nanotubes (SWNTs) using molecular dynamics methods. Particular attention was paid on the non-equilibrium dynamics at the interface between SWNT and other materials, which strongly manifests in nanoscale. In the first part, we have investigated the heat transport through the interface between SWNTs and surrounding argon matrices in liquid and solid phases. By analyzing the energy relaxation from SWNT to the matrices using non-stationary molecular dynamics simulations, elastic and inelastic thermal energy transports across the interface were separately quantified. The result reveals that the elastic interaction transports energy much faster than the inelastic one, but carries much smaller energy due to slow intra-SWNT phonon relaxation. In the second part, we have investigated a possibility to utilize nonequilibrium thermal interface to transport water through an SWNT. By applying the longitudinal temperature gradient to the SWNT, it is demonstrated that the water cluster is efficiently driven at average acceleration proportional to the temperature gradient. However, the transport simulations with a junction of two different SWNTs suggest that an angstrom diameter difference may result in a significant drag for small diameter SWNTs.

Thermal Instability in Plane Poiseuille Flow

1970 ◽  
Vol 92 (1) ◽  
pp. 61-68 ◽  
Author(s):  
W. Nakayama ◽  
G. J. Hwang ◽  
K. C. Cheng
Keyword(s):  
Temperature Gradient ◽  
Flow Direction ◽  
Characteristic Parameter ◽  
Parallel Plates ◽  
Longitudinal Temperature Gradient ◽  
Longitudinal Temperature ◽  
Longitudinal Wall ◽  
Tollmien Schlichting ◽  
Prandtl Numbers ◽  
Basic Temperature

The conditions marking the onset of longitudinal columnar vortices due to buoyant forces are studied for fully developed laminar flow between two infinite horizontal parallel plates with nonlinear basic temperature profile. The wall temperatures at the bottom and top plates, T1 and T2, respectively, are assumed to vary linearly in the main flow direction. The nonlinear basic temperature distribution and connective motion due to longitudinal disturbance component give rise to the influence on stability criteria: This influence may be expressed by a characteristic parameter representing the effect of longitudinal temperature gradient. Numerical values for critical Rayleigh numbers based on temperature difference, T1 − T2, are found for various Prandtl numbers and the parameter μ characterizing the effect of longitudinal wall temperature gradient. An increase in value for μ reduces the critical Ra further to a value less than 1708 when T1 > T2, and this tendency becomes pronounced as Pr increases. Results for the cases T1 ≦ T2 also show that the vortex rolls can be caused by the effect of longitudinal temperature gradient. Tentative discussion in terms of Richardson number is made to define the region where columnar vortices have priority of appearance over two-dimensional Tollmien-Schlichting waves. The computed secondary flow streamlines and perturbation temperatures show that the mode of convection motion is also affected by the parameter μ.

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