# Numerical Simulation for Interfacial Forces of Counter-Current Flow over an Inclined Plate

**Numerical
Simulation for Interfacial Forces of Counter-Current Flow over an Inclined
Plate**

Rajesh

K. Singh^{1,2} and Janine E. Galvin^{1},

Xin Sun^{3} and Sankaran Sundaresan^{4}

^{1}Computational Science and

Engineering Division, National Energy Technology Laboratory,

Albany, Oregon 97321, United States

^{2}ORISE Postdoc

Fellow, National Energy Technology Laboratory,

Albany, Oregon 97321, United States

^{3}Fundamental

Computational Sciences Directorate, Pacific Northwest National Laboratory,

Richland,

Washington 99352, United State

^{4
}Department

of Chemical and Biological Engineering, Princeton University,

Princeton,

New Jersey 08544, United States

CFD

modeling of solvent-based carbon capture is a complex multi-scale

problem. The detailed behavior of the liquid film on the structured

packing element and the flow distribution through the packing are key aspects

influencing the overall efficiency of the column. These scales cannot be

resolved simultaneously within a single computational model. The

two-fluid model (TFM) approach is a suitable technique for modeling large scale

systems; however, it requires closure models for unresolved scales.

Namely, the small scale structures of the interface will influence the mass,

momentum and heat transfer between the phases. The goal of this effort is

to examine the use of volume of fluid (VOF) simulations to develop an

interfacial force model for momentum transfer.

Here

turbulent multiphase flow simulations for countercurrent gas-liquid flow over

an inclined plate are carried out using volume of fluid method (VOF). The

effects of solvent properties on the hydrodynamics of gas-liquid flows are

systematically investigated. Interfacial area and film thickness have been

found to scale well with the Kapitza number.

The advantage of the Kapitza number is that it

only depends on fluid properties and therefore it is fixed for a given solvent.

The computation of the interfacial force at the solid-liquid and solid-gas

interfaces is straightforward. In contrast, computation of the force at the gas-liquid

interface is challenging due to it being a moving and flexible boundary. In

this problem the total interfacial force is computed as the sum of the force

due to shear and the interfacial surface tension force for varying gas/liquid

flow rates and solvent properties. A theory for an interfacial force is

proposed based on the CFD simulated results. The simulation results show that

the liquid-solid drag (wall shear) is always higher than the gas-liquid

interfacial force.

Multiphase

flow simulations are also conducted for countercurrent gas-liquid flow through

a packed column using the TFM approach.Â

In these simulations the packing is treated as a porous region with a

general model for the gas-liquid interaction force.Â Plans are to adopt a more appropriate

mechanism based on the detailed results from the VOF study.