Mechanical Engineering, University of Tabriz
The purpose of the study is to investigate average and local surface heat transfer coefficients in a cylinder packed with spheres. Here the term «local» applies to a single sphere within the bed. Averages are derived from the sixteen different spheres that were instrumented and distributed throughout the bed. The experimental technique consisted of introducing a step - wise change in the temperature of air flowing through the bed and recording the resulting air and ball temperature transients within the bed over a range of Reynolds numbers. An overall correlation of heat transfer with Reynolds number is derived and compared to others available in the literature, and comment is given on the observed patterns in the local coefficients. Comparison is made to theoretical transients.