Microstreaming of a Pneumatically Controlled Bubble under Hydrostatic Pressure and Crossflow.

Area of Science:

• Fluid dynamics
• Membrane science
• Bubble dynamics

Background:

• Membrane fouling significantly impacts separation efficiency and process economics.
• Traditional microstreaming bubbles are limited by gas compressibility under process conditions.
• Atmospheric gas bubbles lose effectiveness due to pressure and crossflow in membrane systems.

Purpose of the Study:

• To investigate the microstreaming effects of a pneumatically controlled bubble.
• To assess the bubble's performance under varying hydraulic pressure and crossflow.
• To determine the feasibility of pneumatic microstreaming bubbles (PMBs) for membrane fouling mitigation.

Main Methods:

• Development of a pneumatically controlled bubble system allowing adjustment of position, shape, and internal pressure.
• Testing PMB performance under hydraulic pressures up to 20 psi.
• Evaluating PMB effectiveness with crossflow velocities up to 19.3 mm/s.

Main Results:

• Pneumatic microstreaming bubbles (PMBs) generate effective bulk fluid streaming.
• PMBs maintain performance under hydraulic pressures up to 20 psi.
• Effective streaming was observed at crossflow velocities up to 19.3 mm/s, within typical membrane process ranges.

Conclusions:

• Pneumatic microstreaming bubbles offer a promising solution for membrane fouling mitigation.
• PMBs overcome the limitations of traditional gas bubbles in membrane separation processes.
• Further research is needed to address challenges for practical integration of PMBs.