A semi-empirical model of the forward roll coating flow of newtonian fluids

✍ Scribed by H. Benkreira; M.F. Edwards; W.L. Wilkinson

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 412 KB
• Volume: 36
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(81)85024-5

✦ Synopsis

Ah&art--A theory of the forward roll coating Row of Newtonian fluids has been developed recently by Greener and Middleman [I] utilizing the usual lubrication approximations and some very simple physical notions regarding the region in which the total flux through the nip splits into two films. These basic notions restricted the validity of their model to the simple case of two rolls of equal rotational speeds and equal radii. Their analysis resulted in an expression for the dimensionless total flux through the nip A as a weak function of a modified capillary number N. The aim of this paper is to extend the model presented by these workers [II by introducing to it experimental evidence of the flux distribution[2] and thus generalizing its applicability to operations involving rolls of different diameters rotating at different speeds. The results of this extended model give the dimensionless total flux A as a function of the modified capillary number N, the speed ratio rs and the radius ratio r, This function is a weak one over the range of N, r. and r, normallv encountered in forward roll coating operations and is in good agreement with experi&ental data-[2].