Numerical simulations for electro-osmotic flow of PTT fluids in diverging microchannel

Abstract

In the current work, the electroosmotic coupled pressure driven flow through a diverging microchannel has been numerically investigated for the simplified Phan Thien Tanner (PTT) fluids. The Debye-Hückel approximation is used for the linearization of electric potential distribution in the electric double layer and the Debye length has been kept fixed (κH = 20). The pressure and electroosmotic forces are coupled and by, Г, the forcing ratio (the ratio of pressure to the electrokinetic gradient in the direction of flow), which is varied in the range of −4 ≤ Г ≤ 4. The viscoelastic fluid rheology has been modulated by the combined effect of the characteristic Deborah number and the PTT parameter as 0.1 ≤ ε De ≤ 5. The influence divergent angle (5° ≤ α ≤ 15°) has also been demonstrated to analyze the role of channel geometry on the resulting flow kinematics. The resulting variations in the flow field have been presented and discussed in the form velocity vectors, surfaces and velocity profiles at the outlet of the channel.