Effecitve heat transfer in oscillating flows
S.R. Perez-Becker , S. Celis , S. Cuevas , J.A. del Río

Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico

Abstract: Previous studies of axial heat transport in a laminary oscillatory flow, with no net mass flow, have shown that an effective thermal diffusivity could be achieved, and it was several orders of magnitude larger than the molecular thermal diffusivity. These studies were mostly theoretical and an experimental corroboration was needed. In this poster we analyze the effective thermal diffusivity in a series of experiments. We study the axial heat transfer in a circular tube with a constant cross section using an oscillating Newtonian fluid under thermal conducting and insulating tubes. The experiments show that, in spite of complying with almost all of the theoretical assumptions, no substantial increase of the effective thermal diffusivity could be observed when compared to the molecular thermal diffusivity present in another reference tube. An explanation of these results is proposed via the introduction of the concept of tidal displacement. Calculations for a group of Newtonian and Maxwellian Fluids were made with the purpose of finding suitable parameters for which an actual improvement on the axial heat transport could be observed.