Periodic Open Cellular Structures with Streamlined Elliptical Struts for the Intensification of Mass Transfer-Limited Catalytic Reactors

We envision periodic
open cellular structures (POCS) with streamlined
elliptical struts as potential intensified structured catalytic supports.
Streamlined elliptical struts aligned to the flow direction substitute
conventional cylindrical ones, aiming at reducing the pressure drop
while increasing the surface area for catalyst deposition. Reactive
computational fluid dynamics simulations are employed for the fundamental
investigation of mass transfer coefficients and friction factors.
The effects of the design parameters (i.e., porosity ε, angle
between the struts’ axis and the streamwise direction α
and elliptical strut elongation R) are evaluated.
The POCS transport properties are significantly affected by increasing
ellipse elongation R and decreasing the angle α.
For low R, the same Sherwood number and friction
factor are obtained as those for the regular diamond lattice with
circular struts. For high elongation, the geometry approaches a honeycomb-like
shape, and the properties of the honeycomb are recovered as asymptotic
conditions. Decreasing α results in a streamlined structure
with a reduced friction factor and a reduced transport coefficient,
consistent with previous observations for POCS with circular struts.
The effects of α and R on the transport coefficient
and friction factor cannot be decoupled from individual contributions.
To address this complexity, a machine learning-aided approach was
proposed for the prediction of the mass transfer coefficients and
friction factors of the POCS as a function of the design parameters.
POCS with intensified properties are characterized by a 2-fold larger
trade-off index between transport coefficient and pressure drop than
the state-of-the-art honeycomb. These advantages are manifested across
various operating conditions and design parameters of the POCS, showcasing
its high flexibility in manufacturing.