Wall heat transfer in static and rotating 180 degrees turn channels by quantitative infrared thermography

The aim of the present study is to develop a new experimental methodology that allows one to perform accurate measurements of the local heat transfer distribution before, in, and after a 180 degrees sharp turn in static and rotating channels. Preliminary measurements of convective heat transfer coefficients are performed by means of infrared thermography applied to the steady state 'heated-thin-foil' technique. Some preliminary results in terms of Nusselt number Mu distributions and profile, as well as averaged Nu profiles along the channel axis, are presented. Results prove that infrared thermography is capable of measuring heat flux coefficients and detecting particular phenomena linked to the fluid flaw configuration such as location of separation bubbles, influence of the channel aspect ratio as well as the influence of the channel rotation. (C) Elsevier, Paris.