caa a22 4500 463235088 CHVBK 20180405153254.0 cr unu---uuuuu 170326e20071201xx s 000 0 eng 10.1007/s10404-007-0162-7 doi (NATIONALLICENCE)springer-10.1007/s10404-007-0162-7 Single-phase laminar and turbulent heat transfer in smooth and rough microtubes [Elektronische Daten] [G. Celata, M. Cumo, S. McPhail, G. Zummo] An experimental campaign was carried out studying laminar and turbulent heat transfer in uniformly heated smooth glass and rough stainless steel microtubes from 0.5mm down to 0.12mm. Heat transfer in turbulent regime proved to be coherent—within experimental accuracy—with the classic Gnielinski correlation for the Nusselt number. For the laminar case, an anomalous drop in Nusselt number for decreasing Reynolds number was observed in the smooth glass tubes. As the stainless steel tubes manifested relatively normal diabatic behaviour in this regime (apart from the evident influence of the thermal development region that increases heat transfer above the thermally fully developed value), the explanation of this unexpected diminution of the Nusselt number must be sought in the dispersion of heat, put in externally through the thin film deposited on the glass tube outer surface, to peripheral attachments to the test section. This distorts the measured energy balance of the experiment, especially as the convective force of the fluid diminishes, resulting in lower Nusselt numbers at lower Reynolds numbers. Springer-Verlag, 2007 Microtubes nationallicence Local Nusselt number nationallicence Wall axial conduction nationallicence Peripheral heat loss nationallicence Celata G. ENEA, Institute for Thermal Fluid Dynamics, Via Anguillarese 301, 00060 S.M., Galeria, Rome, Italy aut Cumo M. University of Rome La Sapienza, Corso Vittorio Emanuele II, 244, Rome, Italy aut McPhail S. ENEA, Institute for Thermal Fluid Dynamics, Via Anguillarese 301, 00060 S.M., Galeria, Rome, Italy aut Zummo G. ENEA, Institute for Thermal Fluid Dynamics, Via Anguillarese 301, 00060 S.M., Galeria, Rome, Italy aut Microfluidics and Nanofluidics Springer-Verlag 3/6(2007-12-01), 697-707 1613-4982 3:6<697 2007 3 10404 https://doi.org/10.1007/s10404-007-0162-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10404-007-0162-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Celata G. ENEA, Institute for Thermal Fluid Dynamics, Via Anguillarese 301, 00060 S.M., Galeria, Rome, Italy aut NATIONALLICENCE 700 1- Cumo M. University of Rome La Sapienza, Corso Vittorio Emanuele II, 244, Rome, Italy aut NATIONALLICENCE 700 1- McPhail S. ENEA, Institute for Thermal Fluid Dynamics, Via Anguillarese 301, 00060 S.M., Galeria, Rome, Italy aut NATIONALLICENCE 700 1- Zummo G. ENEA, Institute for Thermal Fluid Dynamics, Via Anguillarese 301, 00060 S.M., Galeria, Rome, Italy aut NATIONALLICENCE 773 0- Microfluidics and Nanofluidics Springer-Verlag 3/6(2007-12-01), 697-707 1613-4982 3:6<697 2007 3 10404 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer