Mathematical modelling of a dip-coating process using a generalised newtonian fluid. 2. Model validation and sensitivity analysis

Abstract

Dip coating is a simple, straightforward, and economical technique used in many food industrial applications. The objective of this work was to validate a mathematical model (presented by the authors in a companion paper as Part 1) of the fluid-dynamic variables in a dip-coating process considering that the film-forming fluid behaves as a generalized Newtonian fluid, with data obtained from literature, and to perform a sensitivity analysis. A validation process was carried out using experimental data of average film thickness of different film-forming fluids (commercial milk chocolate, commercial deep-fat frying batters, glycerol/water solutions, sugar/syrup solutions, glycerine/water solutions, mineral oil, and Carbopol solutions). On the basis of the low errors obtained, predictions were considered satisfactory. An extensive examination of the effect of the main process variables, such as t0, K, n, m, Up, rho, theta and h, on the velocity profile and the characteristics of the local and average film thickness was established.