J. Appl. Environ. Biol. Sci., 5(2)96-105, 2015 © 2015, TextRoad Publication ISSN: 2090-4274 Journal of Applied Environmental and Biological Sciences www.textroad.com *Corresponding Author: Zeeshan, Department of Mathematics, Abdul Wali Khan University, Mardan, KPK, Pakistan. Email: zeeshansuit@gmail.com, Exact Solution of PTT Fluid in Optical Fiber Coating Analysis using Two-layer Coating Flow Zeeshan 1 , Saeed Islam 1 , Rehan Ali Shah 2 , Ilyas Khan 3 , Taza Gul 1 1 Department of Mathematics, Abdul Wali Khan University, Mardan, KPK, Pakistan 2 Department of Mathematics, University of Engineering and Technology, Peshawar, KPK, 3 Department of Basic Sciences College of Engineering Majmaah University, P.O. Box 66, Majmaah 11952, Saudi Arabia. Received: October 22, 2014 Accepted: January 1, 2015 ABSTRACT To investigate double-layer resin coating of optical fiber glass is, hereby, conducted on the wet-on-wet process. For this purpose the PTT (phan Thien Tanner) model was adopted for this study. As a simple, the coating process in the primary and secondary coating die was taken of two immiscible Non-Newtonian viscoelastic PTT fluids of different viscosities with a signed pressure gradient. The problem of heat transfer analysis is considered in optical fiber coating analysis. Exact solution for the velocity, shear stress, volume flux and temperature distribution for the primary and secondary coating die are obtained. Thickness of coated fiber optic in both layers is also calculated. The effect of Brinkman number  1 , Deborah number  1 2 , characteristics velocity  1 and radii ratio  on the velocity, temperature, volume flow rate, shear stress and on the thickness of the coated fiber optics is discussed and sketched. It was found that velocity increases with increasing values of these parameters. The volume flow rate increases with increasing  1 2 and . The thickness of coated fiber optic increase with increasing of  1 2 and . It is found that the shear stress and force on the fiber increase with increasing 1 2 . The temperature depends upon  1 ,  1 2 and  1 , and it increases with increasing these parameters KEYWORDS: PTT fluid, Opticalfiber coating, Two-layer coating Flows, WOW coating, Pressure Gradient is constant, incompressible fluid. 1 INTRODUCTION The flow of non-Newtonian fluids has attained substantial importance owing of its applications in different branches of science and engineering: particularly in chemical industries, bio-engineering and material processing. It is a well-known reality that the characteristics of non-Newtonian fluids are relatively different when compared with the viscous liquids. Therefore, the Navier-Stokes equation is incompressible to explain the behavior of these fluids. Similar to viscous fluids, it is complicated to propose single mathematical model that possess all properties of such fluids. In view of that, various models have been planned to describe the behavior of these fluids. Amongst there are fluids of different types of grade n (Truesdell and Noll [1]), such as second grade fluid, third grade fluid, fourth grade fluid, elastic viscous fluid, Maxwell fluid, Oldroyd B fluid, Oldroyd 8-consatnt fluids, Phan Thien and Tanner fluid, Power law fluids etc, and the first grade fluid are the viscous fluid. Among many, the constitutive equation proposed by Phan-Thien Tanner (PTT) [2] has been the subject of increasingly extensive study in recent year. Oliveira and Pinho [3] studied the problem of fully developed channel and pipe flows of PTT fluids and obtained analytical expression for velocity fields and stress components in both geometries. The corresponding heat transfer problem of fully developed pipe and channel flows of such fluids was also investigated by Pinho and Oliveira [4]. Some other studies regarding PTT fluid have been carried out in [5] and [6]. An optical fiber consists of high purity Silica glass fiber, which is used to carry information in the form light wave signals. Optical fiber is produced through a series of n-line processes; through heated silica perform in a furnace, the glass fiber is drawn. Then the drawn glass fiber is cooled down in a dedicated fiber cooling system. Further this bare fiber glass is coated with polymer, and finally by ultraviolet (UV) curing. Coatings provide protection from mechanical damage. There has been several research efforts in analyzing the coating die flow in optical fiber coating process. Entrance meniscus in a pressurized optical fiber coating applicator is investigated by Revinuter and S. Polymeripoulos in [7]. Dielectric-fiber surface wave guides for optical frequencies are investigated by C. K. Kao in [8]. Stevens et al [9] gives the application of Ultraviolet (UV) coatings to glass optical fiber. T. Wei [10] examined the effect of polymer 96