Flow and Heat Transfer of Microfoams in Horizontal Minichannels

Colloidal gas aphrons (CGA) consists of closely packed minute gas bubbles with diameter ranging from 10 to 100 microns. It is produced by stirring a surfactant solution at high speed in a fully baffled beaker. CGA can be used in various applications such as bioremediation, bioreactors, oil recovery, and fire fighting. This paper reports experimental data for (1) adiabatic flow and (2) convective heat transfer of CGA into five 1.58 × 0.76 mm² mini-rectangular channels. First, it is shown that CGA is a shear thinning fluid. Correlation for the Fanning friction factor as a function of Reynolds number is compared with that of water and macrofoams. Then, the local temperature and heat transfer coefficient along the minichannels are reported as a function of the mass flow rates and imposed heat flux. The heat transfer coefficients for CGA appears to be constant and independent of mass flow rate and imposed heat flux as well known in the case of single phase laminar flow.