Heat Transfer from a Tube Bank in Cross Flow in a Duct

An experimental investigation on heat transfer coefficient is presented from three horizontal tubes in a vertical array in a duct for 500<ReD<6000. A mass transfer measuring technique based on psychrometry chart is used to determine heat transfer coefficient. The diameter of the tubes is 11 mm each spaced 40 mm apart and in-line pitch ratio varies in the range 0.055<D/W<0.22. The experimental results show that the Nusselt number of each tube increases by increasing D/W. Also the increase of the second tube Nusselt number is more than that of the third one.