Evaluation of the thermal boundary layer in the plate of a heat exchanger and the error estimate

In earlier articles a thermal problem of a periodically perforated plate of a heat exchanger has been presented. This model shows five reduced paramet ers: the period epsilon of the distribution of the holes, the relative thic kness e of the plate, and the three numbers of Blot B+, B-, B-c. Different situations according to the order of magnitudes of these parameters have be en examined save those that present a phenomenon of "thermal boundary layer " which is developed in this paper. (C) 1999 Elsevier Science S.A. All righ ts reserved.