NATURAL-CONVECTION OF OPPOSING ASSISTING FLOWS IN VERTICAL CHANNELS WITH ASYMMETRICALLY DISCRETE HEATED RIBS

Both qualitative flow visualization as well as laser holographic interferometry and quantitative temperature measurement are presented for natural convection of air layers in vertical channels (channels A and B) with asymmetrically discrete heated ribs wherein the opposing flow is in channel A and the assisting flow is in channel B. Based on the analyses of the photographs and interferograms, it is suggested that the turbulent flow should be expected when the local modified Rayleigh number is in the range of 1.29 × 107-9.43 × 109 for both channels. The heat transfer data and flow visualization photographs indicate that the present rib geometry and the stratification are two major reasons influencing the temperature of the heated ribs. Average Nusselt number correlations are established in the form {A figure is presented} for channels A and B, respectively. The power dependence strongly indicates that the flow in channel A is turbulent while the flow channel B is laminar. © 1990.