Analytical Solution of Viscous Dissipation Effects of SPTT Viscoelastic Fluids for Purely Tangential Annuli Flow
Advancing the chemical engineering fundamentals
Rheology (T2-4)
Keywords: viscoelastic, analytical, Annuli, viscous dissipation, Simplified Phan-Thien Tanner (SPTT)
Abstract: The flow in a very thin annulus where the gap between two cylinders is much smaller than the inner cylinder radius has been studied while outer cylinder rotates and inner cylinder is stationary. Effects of viscous dissipation of Simplified Phan-Thien Tanner (SPTT) viscoelastic fluid on velocity and temperature profiles have been investigated analytically. Exponential dependence of viscosity and relaxation time on temperature is modeled through Nahme Law. Inner cylinder is in constant temperature but the outer cylinder is subjected to two different thermal boundary conditions, constant temperature and insulated cylinder. Momentum and energy equations are solved by perturbation method and Nahme-Griffith number is considered as a perturbation parameter. The Results show while viscous dissipation increases for both boundary conditions, velocity profiles become nonlinear. For two constant temperature cylinders, increasing of viscous dissipation Na, causes a maximum temperature between two cylinders. While the outer cylinder is insulated, maximum temperature is placed near the insulated wall and increasing of viscous dissipation leads to increment of temperature. The results show, effects of viscous dissipation on temperature and velocity profiles are more considerable while physical properties of fluid depend on temperature.
Presented Thursday 20, 16:20 to 16:40, in session Rheology (T2-4).
