Double-layer Optical Fiber Coating Analysis by Withdrawal from a Bath of Oldroyd 8-constant Fluid

In the present work we explore an approximate solution of the Navier-Stokes equations for optical fiber coating in a pressure type die by withdrawal from a bath of two immiscible Oldroyd 8-conatant fluid under constant pressure gradient in the axial direction using two-layer coating flow. The constitutive equation of motion has been solved by using optimal homotopy asymptotic method (OHAM) for velocity fields. The theoretical analysis of flow rate, thickness of coated fiber optics and shear stress on surface of fiber optics were also derived. Moreover, the flow phenomenon has been studied under the influence of dilatant constant α, the pseudoplastic constant β, constant pressure gradient Ω, viscosity parameter η1, and radii ratio δ. We noticed that with the increase in dilatant constant α the velocity and volume flow rate decrease whereas the thickness of coated fiber optics increases. Further, it is found that the velocity profile increases with increasing in pseudoplastic constant β and pressure gradient Ω. Also, the profile of shear stress decreases with increase of α and increases with increase of viscosity parameter η1 and pseudoplastic constant β. Further, we noticed that the flow rate increases with increase in pseudo plastic constant β and pressure gradient Ω. The behavior of radii ratio δ on coated fiber optics is similar to that of α.