Affiliations: Università degli Studi di Napoli "Federico II",
Dipartimento di Energetica, Termofluidodinamica Applicata e Condizionamenti
Ambientali (D.E.T.E.C.), P.le Tecchio 80, 80125 Napoli, Italy.
Abstract: Infrared (IR) thermography is a two-dimensional, non-contact
technique of temperature measurement which can be usefully exploited in a vast
variety of heat transfer industrial applications as well as research fields.
The present work focuses attention on thermal surface flow visualizations of
several types of fluid flow studied by means of the IR imaging system and in
particular: the flow over a delta wing at angle of attack; the flow generated
by a disk rotating in still air; air jets impinging on a flat wall; the flow
inside a 180deg turn in a static channel with, or without, turbulence
promoters; the flow inside a 180deg turn in a rotating square channel. Each
flow visualization is illustrated through thermographic images and/or Nusselt
number maps. The emphasis is on the capability of the infrared system to study:
laminar-to-turbulent transition and location of primary and secondary vortices
over the delta wing at angle of attack; the spiral vortical structure
developing at transition over the disk; azimuthal structures arising for
certain jet conditions; the influence of the channel aspect ratio (width to
height ratio) on the heat transfer coefficient distribution along the 180deg
turn, as well as the influence of ribs, in the case of static channel; the
influence of rotation for the rotating channel.
Keywords: flow visualization, infrared thermography, convective heat transfer