Laminar convective heat transfer with twisted tape inserts in a tube

A new method is postulated to predict heat transfer coefficients with twisted tape inserts in a tube, in which the wall shear and the temperature gradients are properly modified through friction coefficient correlation leading to heat transfer augmentation from the tube wall. The eddy diffusivity expression of van Driest is modified to respond to the case of the internal flows in a tube with twisted tapes for ranges of Reynolds number corresponding to the laminar flow in tubes. The predictions from the present theory are compared with some correlations available in literature for twisted tape inserts. The present theoretical results are rendered in the form of a correlation equation. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.