variavel0=<b>Élcio Nogueira</b> - elcio@univap.br Universidade do Vale do Paraíba - UNIVAP
<b>Lucília Batista Dantas</b> - lucilia@univap.br Universidade do Vale do Paraiba
<b>Renato Machado Cotta</b> - cotta@serv.com.ufrj.br Universidade Federal do Rio de Janeiro
<b>Abstract.</b> Annular flow and heat transfer of immiscible liquids inside channels have several practical motivations related to pumping of very viscous fluids, heat exchange enhancement, fouling and corrosion reduction, etc. In this work, an analytical solution for the temperature field in the thermal entrance region of vertical annular undisturbed flow of two immiscible liquids is presented, taken as a limiting situation for more general stratified and/or dispersed two-phase flow modeling. The integral transform technique is used to describe the laminar flow heat transfer phenomena, under a constant heat flux boundary condition at the tube wall. To demonstrate its applicability, the theoretical model here proposed has been applied to the analysis of a situation dealing with corrosion and fouling effects reduction, by using a kerosene flow between the wall and water core inside a vertical circular duct. In this system, the heat transfer to the core is expected to be affected by the fact that kerosene has a lower thermal conductivity when compared with water, and we attempt to investigate the heat transfer rate reduction as a function of the kerosene layer relative thickness. The theoretical predictions here obtained are critically compared with previous numerical results available in the open literature.
<b>Keywords.</b> liquid-liquid annular flow, integral transforms, laminar flow, convective heat transfer, fouling reduction.