  The thermo-fluidic transport characteristics of ferrofluids can be influenced
by the application of a magnetic field. The magnetic manipulations of
ferrofluids have been useful in augmenting heat transfer, as evident from
recent investigations. In the present study, we examine a novel strategy for
augmenting two-phase heat transfer and show that the magnetic manipulation of
non-boiling Taylor bubble flow (TBF) of ferrofluids can provide on-demand
augmentation. In an earlier investigation (DOI:10.1016/j.colsurfa.2020.124589),
we had shown that the characteristics of the TBF of ferrofluids could be
altered through external magnetic manipulations. As transport characteristics
of TBFs primarily depend on their flow morphology, it was anticipated that such
alteration would affect their thermal transport characteristics, which are
examined in the present work. The generation of smaller bubbles and unit-cells
through magnetic manipulations decreases the void fraction of the resulting
TBF. In addition, a greater number of units participated in the heat exchange
process compared to larger bubble-slug systems at any time instance. Such flow
modifications cause considerable augmentation (which can go up to 100%) in
two-phase heat transfer. The extent of augmentation depends on the applied
magnetic field and induced magnetic force, homogeneous gas fraction, liquid
film thickness/void fraction and flow morphology of the resulting TBF, which
are examined in the present study. The application of ferrofluids in TBFs
provides multiple benefits, such as suspension of nanoparticles with better
thermal properties and additional functionality of the flow manipulations
through external means. The proposed application with the suggested
manipulation technique provides an effective alternative for an on-demand
augmentation in two-phase heat transfer in low Reynolds number flows.
