Based on the biochemical theory of multiple ligand-receptor complexes (Klotz (1946)) a sigmoidal proceeding adsorption isotherm is derived. The special case of an arbitrarily large number of equal interaction sites and a separate one yields an equation which corresponds to the ζ-isotherm, disparately derived by Ward et al. (2007) for surface tension of solid-fluid interfaces. From the mathematical point of view it is analogous to the BET-isotherm for a limited number of adsorption layers (1938). It is shown that the isotherm maps type IV and V isotherms. The isotherm is compared with others including the type IV isotherm of Do and Do (2009). The present isotherm is unified in contrast to existing hybrid models. It is successfully applied to numerous literature data concerning the adsorption of water on microporous carbon and aluminophosphate molecular sieves.

https://pubs.rsc.org/en/content/articlepdf/2019/cp/c8cp07751g

Modeling of type IV and V sigmoidal adsorption isotherms

The flow in a completely filled rotating cylinder driven by the counter-rotation of the top endwall is investigated both numerically and experimentally. The basic state of this system is steady and axisymmetric, but has a rich structure in the radial and axial directions. The most striking feature, when the counter-rotation is sufficiently large, is the separation of the Ekman layer on the top endwall, producing a free shear layer that separates regions of flow with opposite senses of azimuthal velocity. This shear layer is unstable to azimuthal disturbances and a supercritical symmetry-breaking Hopf bifurcation to a rotating wave state results. For height-to-radius ratio of 0.5 and Reynolds number (based on cylinder radius and base rotation) of 1000, rotating waves with azimuthal wavenumbers 4 and 5 co-exist and are stable over an extensive range of the ratio of top to base rotation. Mixed modes and period doublings are also found, and a bifurcation diagram is determined. The agreement between the Navier–Stokes computations and the experimental measurements is excellent. The simulations not only capture the qualitative features of the multiple states observed in the laboratory, but also quantitatively replicate the parameter values over which they are stable, and produce accurate precession frequencies of the various rotating waves.

Instability and mode interactions in a differentially-driven rotating cylinder

Numerical study on combined buoyancy–Marangoni convection heat and mass transfer of power-law nanofluids in a cubic cavity filled with a heterogeneous porous medium

Entropy generation and natural convection of nanoparticle-water mixture (nanofluid) near water density inversion in an enclosure with various patterns of vertical wavy walls

Review article: Microscale evaporative cooling technologies for high heat flux microelectronics devices: Background and recent advances

Effect of surface heat dissipation on thermocapillary convection of moderate Prandtl number fluid in a shallow annular pool

Experimental study on the flow instability of a binary mixture driven by rotation and surface-tension gradient in a shallow Czochralski configuration

Aspect ratio and capillary ratio dependence of thermal-solutal capillary-buoyancy flow of a binary mixture in an annular pool

In order to investigate the energy transfer mechanism and the nonequilibrium effect during water evaporation in its own pure vapor at low pressures, a series of precise measurements are conducted to obtain the temperature profile near the liquid-vapor interface and the evaporation rates in an annular pool in a closed chamber. The results show that the interface temperature of the vapor side is higher than that of the liquid side when water evaporates in its own pure vapor at low pressures (ranging from 394 to 1467 Pa), the temperature discontinuity across the interface exists in all experimental conditions. The magnitude of the temperature discontinuity is strongly affected by the vapor pressure. A uniform temperature layer with a thickness of about 2 mm is found below the evaporating interface because of the coupling effect of evaporation cooling and thermocapillary convection. The energy required for evaporation is mainly transferred by thermocapillary convection in the uniform temperature layer. Furthermore, the numerical simulation results confirm that the evaporation flux near the cylinders is much larger than that at the middle region, which implies that most of the latent heat required for evaporation is transferred to the interface near the cylinders.

Study on Evaporation Characteristics of Water in Annular Liquid Pool at Low Pressures.

This paper presented a series of numerical simulations on thermocapillary convection for mixed toluene/hexane solution with mass fraction of $c_{0}= 26.27$
 % in a shallow annular pool. The Prandtl number of the binary solution is 5.54. Results indicate that when the annular pool subjects to a radial temperature gradient, the solute shifts toward the inner wall under the Soret effect, which leads to a concentration gradient with the opposite direction to the temperature gradient. With the increase of surface heat dissipation, thermocapillary convection is enhanced and the flow is more prone to destabilization. Therefore, the critical thermocapillary Reynolds number of the flow destabilization and the corresponding critical oscillation frequency all decrease, but the critical wave number increases. After flow destabilization, the concentration fluctuation similar to the temperature fluctuation on the free surface appears. No matter the free surface is adiabatic or not, the flow always undergoes a transition from two-dimensional steady axisymmetric flow to the hydrothermal waves, and then to chaos with the increase of thermocapillary Reynolds number.

Chun-Mei Wu

Papers

Effect of surface heat dissipation on thermocapillary convection of moderate Prandtl number fluid in a shallow annular pool

Experimental study on the flow instability of a binary mixture driven by rotation and surface-tension gradient in a shallow Czochralski configuration

Aspect ratio and capillary ratio dependence of thermal-solutal capillary-buoyancy flow of a binary mixture in an annular pool

Study on Evaporation Characteristics of Water in Annular Liquid Pool at Low Pressures.

Thermocapillary Convection in a Binary Mixture with Moderate Prandtl Number in a Shallow Annular Pool