Three-dimensional simulation of rivulet and film flows over an inclined plate: Effects of solvent properties and contact angle

• Film and Rivulet flows over an inclined plate for a wide range of solvents used in the industrial carbon capture process.
• Correlation established for interfacial area of rivulet with Kapitza number, Reynolds number, contact angle and inclination angle.
• Developed rivulet’s width is independent of inlet size at a fixed flow rate.
• Demarcation of two regimes for variation of interfacial area with contact angle.

We numerically investigated the film flow down an inclined plate using the volume of fluid (VOF) method. The flow simulations have been systematically carried out for a wide range of parameters, such as inlet size, inclination angle, contact angle, flow rates and solvent properties (viscosity and surface tension). Based on the simulation results, scaling theory is proposed for both interfacial area and for film thickness in terms of the Kapitza number (Ka).The Kapitza number is advantageous because it depends only on solvent properties. The Kapitza number decreases with increased solvent viscosity and is fixed for a given fluid. To investigate the effects of solvent properties on interfacial area a small inlet cross-section was used. The interfacial area decreases with increased value of Ka. The time to reach pseudo-steady state of rivulet is also observed to increase with decreasing Ka. For a fixed flow rate, the inlet cross-section has marginal effect on the interfacial area; however, the developed width of the rivulet remains unchanged. In addition to inlet size, flow rate and solvent properties, the impact of contact angle on film thickness and interfacial area was also investigated. The contact angle has negligible effect for a fully wetted plate, but it significantly affects the interfacial area of the rivulet. A scaling theory for interfacial area in terms of the contact angle and Ka is presented.