Loading...

CFD Simulation of a Polymeric Solution Flow in Doctor Blade Film Coating Process for Pruducing Desirable Thin Film

Mollataheri, Mehdi | 2015

689 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50275 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Mohammadi, Ali Asghar; Musavi, Abbas
  7. Abstract:
  8. Lately, some investigators of polymer engineering group are working to do continuous polymer solution casting process, rather than batch process for flat sheet membrane production. For this, they use a doctor blade system but, they faced some problems during coating process. From experimental observations of the studied system, some inappropriate vorticities were seen. That’s why the system forms a non-uniform film of the solution. Air bubbling occurs at system exit which is undesirable as well. In this study simulation and optimization has been done for forming thin film in doctor blade system. COMSOL Multiphysics 4.3b was used in purpose of simulating which works on numerical finite element method. The case study solution was 17% wt polysulfone in DMF. By using the rheology resulted from experiments, the solution behavior under various transformations acts like pseudoplastic solutions, which based on Ostwald-de Waele power-law equation, its viscosity is modelled in terms of rate of strain. The flow in main system was simulated with available parameters and big vorticities was observed which corresponds to experimental results. Although, it was observed by checking pressure changes in the channel under doctor blade, exit flow and free surface along the web that the downstream pressure reaches negative values which could be the reason for air intake and bubbling in the thin film. To check various parameters of system on solution flow, statistical analysis was made by using Design Expert 7.0 software and box-behnken method. Several experiments was obtained through the method and 43 simulations was done for 5 effective parameters. The results of these simulations was defined to the software which finally led to good models for considered responses. By analyzing the models, recommended conditions were obtained for these 5 parameters
  9. Keywords:
  10. Surface Tension ; Fluid Dynamics ; COMSOL Software ; Computational Fluid Dynamics (CFD) ; Polymeric Solution ; Operating Condition ; Film Coating ; Doctor Blade

 Digital Object List

 Bookmark

No TOC