Experimental and numerical investigation of the influence of nozzle design on the industrial convection drying of thin films

Abstract

Analytical simulation is a powerful tool for the optimization of the convective drying of continuous thin film coatings. Knowledge of the heat transfer coefficient is a prerequisite for applying such simulations. In this work, the heat transfer coefficient distributions in industrial dryers with oblique twin nozzles is investigated. Convergent nozzles show higher heat transfer than divergent nozzles. The results are used as boundary condition for a dryer simulation, which is in good agreement with experimental data. An alternative nozzle design, using a wider outlet area and a lower velocity is also investigated. A more homogeneous local Nusselt number is observed.

Keywords:

• Drying
• thin film
• CFD
• heat transfer
• nozzle design

Declaration of interest

No potential competing interest was reported by the authors.