CONVECTION HEAT-TRANSFER DISTRIBUTIONS OVER PLATES WITH SQUARE RIBS FROM INFRARED THERMOGRAPHY MEASUREMENTS

Heat transfer measurements were performed on two ribbed plates, with constant heat flux surfaces, using an infrared (IR) thermography technique. The tests were conducted in a turbulent flow wind tunnel (0.5 x 10(6) < Re < 1.5 x 10(6)) at two roughness heights (e/D(h) = 0.052 and 0.093). The transverse ribs on the plates had a square cross section. The experimental technique provided local variations of heat transfer coefficients not only between ribs but also surrounding the ribs, with better resolution than techniques currently used. The results suggested a separation-reattachment flow distribution over the plate with a pitch ratio (p/e) of 12 and a trapped vortex flow between ribs for a p/e of 5.