Analyse expérimentale des transferts de chaleur en espace annulaire étroit et rainuré avec cylindre intérieur tournant

A review of heat transfer between concentric rotating cylinders with or without axial flow

“…Becker and Kaye [36] observed a second, less pronounced transition (simple modification of slope) for Ta ¼ 10 4 . The results were confirmed in the respective works of Nijaguna and Mathiprakasam [37] as well as Bouafia et al [12,14]. There would appear to exist another dynamic transition or differing flow behavior altering the evolution of convective heat transfer.…”

“…Moreover, Nijaguna and Mathiprakasam [37] provide no explanation as to the significance of the critical s value assumed at 4.817. This value may perhaps be linked to the «transition» observed by Becker and Kaye [36] and by Bouafia et al [12,14] for Ta ¼ 10 4 in a case without axial flow (Fig. 8).…”

“…Most authors have formulated the Nusselt number through experimental correlations of the aspect Nu ¼ ATa n with A and n of the constants depending a priori on the aspect ratio of the cylindrical gap. Several precise correlations have been put forward by different authors, among whom we wish to cite Becker and Kaye [36], Tachibana and Fukui [35] and Bouafia et al [12,14]. These correlations and the conditions of use are reported in Table 1.…”

“…The Nusselt number thereby deduced serves as a translation of the efficiency of heat transfer from one wall to the other by means of the fluid. As for the heat transfer surface S, it is often defined as the surface of the heating wall (S ¼ 2$pLR 1 or S ¼ 2$pLR 2 [13]) Sometimes this surface is considered as intermediate with regard to the walls, and its exact definition differs from one author to the next (generally S ¼ 2$pLðe=lnð1=hÞÞ [14]). The more narrow the cylindrical gap, the smaller the differences between the definitions of S. Some authors do not use the hydraulic diameter as the characteristic length, but rather prefer the thickness of the annular gap:…”

“…Becker and Kaye [36] decided to maintain the distinction between the two walls, but they could compare their results only to the temperature at entrance of a given fluid; they could not dissociate the heat transfer on each one of the walls. The mean temperature calculated from the enthalpy assessment utilized by Bouafia et al [14] in particular seems to be the most physically accurate, but also the most difficult to obtain experimentally. An intermediate solution occasionally adopted (by Grosgeorge [45] for instance) involves calculation of the mean value between entrance and exit temperature.…”