Deposition of spherical particles onto cylindrical solid surfaces. I. Numerical simulations

Area of Science:

• Colloid and Surface Science
• Mass Transfer Phenomena
• Computational Fluid Dynamics

Background:

• Particle deposition is crucial in various industrial and environmental processes.
• Understanding the interplay of colloidal forces is key to predicting deposition rates.
• Existing models often simplify the complex interactions involved.

Purpose of the Study:

• To provide analytical and numerical solutions for spherical particle deposition onto cylindrical surfaces.
• To investigate the influence of van der Waals (vdW) and electrical double-layer (EDL) forces on deposition.
• To examine the effects of gravity and external electrical forces on the deposition process.

Main Methods:

• Development of analytical and numerical solutions for a 1D mass transfer equation.
• Parametric study of vdW (adhesion number Ad) and EDL forces (EDL parameter Dl, reduced radius tau).
• Numerical solution of a 2D boundary value problem using the implicit Crank-Nicolson method for external forces.

Main Results:

• The attractive vdW force is essential for deposition but has a limited effect on mass transfer rate.
• The 1D deposition process is predominantly controlled by the EDL force, with tau being a critical factor.
• External forces like gravity and electrical fields introduce 2D effects, altering deposition dynamics.

Conclusions:

• The EDL force is the dominant factor in 1D particle deposition on cylindrical surfaces.
• The adhesion number (Ad) is necessary but not sufficient for significant deposition.
• Gravity and electrical forces introduce complexities requiring 2D modeling for accurate prediction.