Gas-liquid Interaction Research Articles

Modeling of wavy flow in inclined thin films in the presence of interfacial shear

A physical model is presented for predicting the various roll-waves characteristics in inclined thin films and in the presence of various distributions of interfacial shear and external pressure drop. The model is based on a periodical distortion of the hydrodynamic boundary layer in the wave front, followed by a recovery process in the wave trail. The solution is a closed form at the inception or at the well-developed regions, where the frequency is also predicted. For the developing region, one input (frequency) is required. A satisfactory agreement between predicted wave characteristics and experimental data is obtained, particularly at the low-intermediate interfacial shear range. With increasing the interfacial shear, both the wave frequency and wave velocity increase, while the wave amplitude decreases, independently with the mode of interfacial shear distribution. Applying the present model for various prescribed shear distributions, while comparing with available data of measurable wave characteristics, stimulates some thoughts on the unresolved gas-liquid interactions.

Interfacial area and liquid side mass transfer coefficient in trickle bed reactors operating with organic liquids

Interfacial area and liquid-side mass transfer coefficients measured in a 5cm diameter trickle-bed reactor operating with organic liquids are presented d p≤ 2.4 mm and cylindrical catalyst of size 0.9 mm × 5 mm. A few data concern also 5.9 and 6.4 mm Raschig rings. Gas and liquid flowrates a Mass transfer parameters have been determined by the chemical technique using the carbamation of the reactants cyclohexylamine, monoethanolamine or die results obtained at low gas-liquid interaction with low liquid flowrate are reported for the ionic aqueous systems CO 2-NaOH and O 2-Na 2SO 3. The variation of the mass transfer data, the gas pressure drop and the liquid holdup with the gas and liquid flowrates show that there exists a strong connection between these parameters. This has led to correlate the with the liquid-solid friction factor within a + 30% accuracy.

Stability of a coupled reaction diffusion system

This note is concerned with the stability property of positive steady-state solutions of a coupled reaction-diffusion system which is motivated by the problem of gas-liquid interaction. It is shown that for any non-negative initial function the corresponding time-dependent solution converges to a unique steady-state solution, and for a certain class of initial functions the convergence of the time-dependent solution is monotone in time.

Axial dispersion processes in liquid trickle flow through packed beds

The axial dispersion in the liquid phase of a trickle-bed column is mainly affected by velocity distributions appearing at the particle and bed scales. At the particle scale, this phenomenon is respresented by a laminar pore flow model (regime of low gas-liquid interactions). At the bed scale, the axial dispersion is analyzed using a lattice approach based on the percolation theory. We propose a theoretical expression for the axial dispersion coefficient evidencing the influence of the fluid flow hydrodynamics and, more specifically, of the particle irrigation rate. A decrease of this parameter leads to an increase of the dispersion coefficient. The model is compared with various experimental data. Good agreement is obtained for the influence of the liquid viscosity and the particle wettability.

A mathematical model for gas-liquid interaction in the turbulent reacting flows

A mathematical model for gas-liquid interaction in the turbulent reacting flows

Hydrodynamic and Hydraulic Studies on Void Fractions in Two-Phase Flow

For gas-liquid two-phase flow, two kinds of fundamental equations have been proposed by the methods of hydrodynamics and hydraulics. The hydrodynamic equation, to avoid analytical difficulties, does not deal with two-phase flow itself, but with a hypothetical liquid flow which has actual physical quantities in the region where the liquid phase really exists and has the imaginary physical quantities of liquid in the region where the gas exists, for each instant, and with a hypothetical gas flow similarly. The hydraulic equation differs from the usual form in the treatment of friction term or interaction, and has better physical insight. These equations are analyzed mathematically and some relationship between physical quantities centering void fraction are discussed. Hydrodynamic equation shows the void fraction distribution to have relation to pressure loss and velocity distributions, and, for the case of laminar two-phase flow with axial symmetry, explicit expression is presented. By hydraulic equation, the relation between void fraction and other variables are discussed. For the upward two-phase flow with constant flow area, gas-liquid interaction force is discussed theoretically and experimentally.

Pressure drop and liquid holdup for two phase concurrent flow in packed beds

Pressure drop and liquid holdup for two-phase concurrent downward flow in packed beds were correlated for various types of packings by taking into account two hydrodynamic regimes: a poor and a high gas-liquid interaction regime. Foaming and non-foaming systems have been considered. In the poor interaction regime, the pressure drop was calculated as due to the gas flowing in a bed restricted by the presence of the liquid. A correlation valid for a free liquid trickling, modified in order to take into account the effect of the pressure drop, is proposed and used to correlate liquid holdup in the presence of a concurrent gas flow. In the high interaction regime, empirical correlations were proposed for both foaming and non-foaming systems. All the employed correlations fit experimental results from several authors better than those proposed in the literature.

Liquid droplets vaporization under free molecule gas beam conditions

The present piece of research studies the vaporization of liquid droplets under rarefied gas beam conditions. The time dependent aspect of the phenomenon has been taken into account. In fact, during the vaporization, variations of the droplet's temperature, with influence upon the diameter's reduction rate, can occur. Numerical calculations relating to water droplets' vaporization have been made taking into account various values of the incident energy flux. The study should be considered as a theoretical approach to the analysis of the gas-liquid surface interaction phenomena. Moreover, according to C. S. Kurzius and F. H. Raab [1], the work can find its application in the study of the blackout suppressant methods in re-entry space vehicles.