Design of Improved Flow-Focusing Microchannel with Constricted Continuous Phase Inlet and Study of Fluid Flow Characteristics

Abstract

This paper proposed an improved flow-focusing microchannel with a constricted continuous phase inlet to increase microbubble generation frequency and reduce microbubbles’ diameter. The design variables were obtained by Latin hypercube sampling, and the radial basis function (RBF) surrogate model was used to establish the relationship between the objective function (microbubble diameter and generation frequency) and the design variables. Moreover, the optimized design of the nondominated sorting genetic algorithm II (NSGA-II) algorithm was carried out. Finally, the optimization results were verified by numerical simulations and compared with those of traditional microchannels. The results showed that dripping and squeezing regimes existed in the two microchannels. The constricted continuous phase inlet enhanced the flow-focusing effect of the improved microchannel. The diameter of microbubbles obtained from the improved microchannel was reduced from 2.8141 to 1.6949 μm, and the generation frequency was increased from 64.077 to 175.438 kHz at the same capillary numbers (Ca) compared with the traditional microchannel. According to the fitted linear function, it is known that the slope of decreasing microbubble diameter with increasing Ca number and the slope of increasing generation frequency with increasing Ca number are greater in the improved microchannel compared with those in the traditional microchannel.

Advances in Thermal Process Engineering and Simulation

“…In [4], the authors optimize the structural parameters of a multi-stage Tesla valve battery thermal management system using the neighborhood cultivation genetic algorithm (NCGA) and the Kriging approximation model to find the optimal values of the cooling plate by considering different design parameters.…”

Microbubble formation by flow focusing: role of gas and liquid properties, and channel geometry

“…Numerical studies are mainly available for the squeezing regime (mostly Taylor bubbles, i.e. bullet-shaped bubbles filling almost the entire channel cross-section) and besides liquid viscosity (Jia & Zhang 2020;Chekifi, Boukraa & Aissani 2021) and surface tension (Chekifi et al 2021), they focus on the role and optimization of the channel geometry (Dietrich et al 2008;Wang et al 2022).…”