Laminar heat transfer to Newtonian and non-Newtonian fluids in tubes

✍ Scribed by F. Popovska; W.L. Wilkinson

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 888 KB
• Volume: 32
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(77)80047-x

✦ Synopsis

A theoretical treatment IS presented which allows radml temperature and velocity profiles and the axial pressure profile to be pre&cted when VLSCOUS Newtoman and non-Newtonian flmds are heated or cooled m lammar flow m cucular tubes The overall heat transfer rate can also be pre&cted m the form of a mean Nusselt number Particular attention has been grven to the effect of temperature on the rheologzil propertres and a polynonual expression has been used to descnbe tlus effect The theoretical predictions have been conlirmed by comparmg them urlth expenmental temperature and velocity profiles obtamed for a Newtoman ol and non-Newtoman polymer solutions Both heatmg and coohng expenments have been carned out for a range of Reynolds numbers from Z-700 The Graetz number vanahon was from 80-1600 The experlmental Nussek numbers were also compared with the theoretlcal predIctIons and with those calculated from the generally accepted design correlations of the LeviZque form Whereas the agreement between the theoretical predictions and the expenmental results was good, empvlcal design correlations gave values wluch were senously m error, particularly for the case of coolmg They should therefore be used vvlth caution d the rheolomcal behavlour of the thud IS sensitive to temperature Empmcal methods for predrctmg the overall pressure drop can also gwe nse to large errors 1155