Mass transfer to fluids flowing through rotating nonaligned straight tubes.

Area of Science:

• Fluid Dynamics
• Heat and Mass Transfer
• Chemical Engineering

Background:

• Low Reynolds number flows in tubular devices exhibit inefficient heat/mass transfer.
• Transverse laminar secondary circulations can augment mass transfer by inducing fluid mixing.
• Coiled tubes offer transport advantages, but straight tubes are simpler in design.

Purpose of the Study:

• To investigate enhanced transport in rotating, nonaligned, straight tubes.
• To utilize Coriolis acceleration for creating transverse fluid mixing and improving mass transfer.
• To couple the benefits of coiled tubes with the design simplicity of straight tubes.

Main Methods:

• Numerical solution of the overall mass balance equation for steady flow.
• Third-order perturbation solution for primary and secondary flow fields under small Coriolis disturbances.
• Experimental measurements of oxygen transfer into water and blood.

Main Results:

• Bulk concentration increase is determined by a single similarity parameter for small Coriolis disturbances.
• Two additional parameters are needed for accurate characterization with increased Coriolis disturbances.
• Increasing Coriolis acceleration generally enhances mass transfer, but can decrease efficiency in specific regimens due to velocity-weighting effects.

Conclusions:

• Rotating nonaligned straight tubes effectively enhance mass transfer through Coriolis-induced mixing.
• The study provides a theoretical framework and experimental validation for this transport enhancement technique.
• Understanding the complex relationship between Coriolis acceleration and mass transfer is crucial for optimal design.