Flow Characteristics of Power-Law Fluids in Coiled Flow Inverter

A novel device coiled flow inverter (CFI) has shown great potential as a heat exchanger and inline mixer.(1-3) The device offers negligible thermal and concentration gradient in the radial direction. CFI may find potential applications in food industry for different processes such as pasteurization and sterilization, due to its ideal characteristic. Therefore, in the present study, the hydrodynamic of single and two-phase non-Newtonian fluid flow in CFI have been investigated experimentally and numerically. The experiments have been performed in three different CFI geometries. The aqueous solution of carboxymethyl cellulose (CMC) of three different concentrations has been used as a working fluid. The single-phase Reynolds number ranged from 100 to 10000, while the two-phase liquid and gas Reynolds numbers ranged from 100 to 10000 and 100 to 8500, respectively. The various flow patterns for two-phase non-Newtonian fluid flow in CFI have been observed during experimental investigation. The effects of the gas and liquid flow rates, curvature ratio and concentration of non-Newtonian fluid on frictional pressure drop have been investigated. The correlation for the friction factor in CFI has been developed for single and two-phase air non-Newtonian fluid flow under laminar condition. The development of velocity fields has been demonstrated for single and two-phase non-Newtonian fluid flow in CFI. The contours of the volume fraction are plotted at different axial length and after each 90 bend. The contour plots bring about an understanding of flow inversion and flow distribution of pseudoplastic fluids after each 90 bend in CFI.