Viscoelastic Fluid Flow in the Entrance of A Tube

by Iraj Zandi,
Abdol R. Razaghi,

Serial Information: Journal of the Engineering Mechanics Division, 1967, Vol. 93, Issue 4, Pg. 117-138

Document Type: Journal Paper


A semi-empirical method is presented which permits the prediction of the entrance length and entrance pressure drop of laminar flow of non-Newtonian viscoelastic fluid into the entrance of a circular tube. The only information required for this calculation is the knowledge of pipe diameter, mean velocity, and rheological parameters of the fluid. In addition, data are presented concerning the laminar flow of aqueous solutions of ET-597, a Dow Chemical long-chain polymer, both in the entrance region and in the established zone. Data for laminar flow in the established zone indicate that the Fanning friction factor, f, and the generalized non-Newtonian Reynolds number, R', have the relationship f = 16/R'. Also, it is found that above a certain mean velocity, which is a function of polymer concentration and pipe diameter, the pressure losses become less for polymeric solutions than for water.

Subject Headings: Fluid flow | Fluid velocity | Laminar flow | Polymer | Viscoelasticity | Dynamic pressure | Pressure pipes | Permits

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