Effect of microbubble-containing two-phase feed flow on the performance of an ultrasonic-assisted non-contact membrane distillation process

초록

The effect of a microbubble-containing two-phase flow on the performance of the ultrasonic-assisted non-contact membrane distillation (NCMD) process was experimentally investigated using seawater as the feed solution. A microbubble generator (MBG) was employed to produce the two-phase flow, and the performances of the ultrasonic-assisted NCMD process with and without the MBG were compared. The heat and mass transfer characteristics were analytically evaluated with respect to the air flow rate (10–100 cc/min) supplied to the MBG. The presence of microbubbles facilitated the formation of a mist of droplets within the air gap, thereby reducing the mass transfer resistance imposed by the air gap and enhancing the permeate flux. The extent of mass transfer enhancement induced by the air flow rate was highly dependent on the applied ultrasonic power. Under specific operating conditions, the permeate flux increased with increasing air flow rate up to 40 cc/min. At an air flow rate of 40 cc/min, feed temperature of 50 °C, and ultrasonic current of 400 mA, the permeate flux reached 2.54 kg/m2∙h, representing an approximately 22% increase compared to the case without microbubbles, accompanied by a reduction in mass transfer resistance from 1.5 × 107 to 1.1 × 107 Pa∙m2∙s/kg. © 2026 Elsevier B.V.

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