Friction Factor Determination for Horizontal Two-Phase Flow Through Fully Eccentric Annuli

Effects of the gap size on the flow pattern maps in a mini-gap annular channel

“…Metin and Ozbayoglu [11] presented correlations of friction factors for two-phase flow in a horizontal eccentric annulus where two sizes of annulus were investigated. Flow patterns in this work were stratified and intermittent.…”

The combined effect of fluid rheology, inner pipe rotation and eccentricity on the flow of Newtonian and non-Newtonian fluid through the annuli

“…However, the Caetano et al (1992) friction factors equations cannot be applied to address the effect of the inner pipe rotation on non-Newtonian annuli fluid flows. Over the years, many mathematical modelling performed for single-phase and two-phase fluid flow in the annuli, have either applied friction factor equations valid for Newtonian annuli flows when dealing with Newtonian fluids, or have applied Newtonian or non-Newtonian friction factor equations that have not taken into consideration the combined effect of the fluid rheology, the eccentricity and the effect of the inner pipe rotation when dealing with non-Newtonian fluid flow through the annuli (Fan et al, 2009;Hasan and Kabir, 1992;Kelessidis and Dukler, 1989;Metin and Ozbayoglu, 2009;Omurlu and Ozbayoglu, 2006). Due to the complexity of the solution of non-Newtonian flow in the eccentric annuli, early theoretical methods where the annulus is modelled as a slit of variable height, by an infinite number of concentric annuli with variable outer radii, or by expressing the annuli in the bi-polar coordinate system in order to derive equations for the velocity profiles and pressure gradient to flowrate relationships (Haciislamoglu and Langlinais, 1990;Iyoho and Azar, 1981;Luo and Peden, 1990;Uner et al, 1988).…”