Pressure drop and bubble length prediction for gas-non-newtonian fluid two-phase flow in a curved microchannel.

The control mechanism of the pressure drop and bubble size has a guiding significance for selecting the micropump, the pressure resistance design, and the precise control of the microfluidics. In this study, single-phase flows and gas-non-Newtonian fluid two-phase flows are studied in a microchannel containing curved structures. Sodium carboxymethyl cellulose solutions are used as the non-Newtonian fluids; water and nitrogen are used as Newtonian fluid and gas phases, respectively. The pressure drop and the bubble length are measured. The influences of operating conditions are discussed. The non-Newtonian properties of the solutions are found to affect the parameters measured significantly. The experimental results are compared with the existing models, and the fanning friction factor is used to evaluate the pressure drop. The two-phase flow pressure drop can be predicted by the Lockhart-Martinelli method with a newly developed C-coefficient as a function of the fluid characteristic parameters and microchannel structure parameters. The new correlation for two-phase pressure drop prediction has an error within 18%, smaller than existing models. A new prediction method for the dimensionless bubble length containing the two-phase friction multiplier is also given with an error of 16%. [Display omitted] • A novel microchannel containing curved structures was studied experimentally. • Empirical models for predicting pressure drop and bubble length were developed and compared with existing models. • The prediction accuracy of the pressure drop was improved by considering structural and non-Newtonian fluid parameters. • The prediction accuracy of the bubble length was improved by considering the influence of pressure drop. [ABSTRACT FROM AUTHOR]