Abstract:
This study concernsanumerical simulationofthree-dimensionalconjugateheat transferin ahorizontal
pipe heatedby Joulean effectthroughits entire thickness.The mixed convection in the fluid domain is
combined with heat conduction in the thickness of the solid duct.The physical propertiesof the
fluidare heatdependent andthermal losses,the outer surfaceofthe conduit tothe environment,
aretaken into consideration. At the entranceof the pipe,the fluidispresentedwitha constant
temperatureequal to 15C°andaparabolicvelocity profile. The numerical methodoffinite volumeis
used forsolving the equationsofconservation ofmass,momentum and energy. The resultsof this study
areperformedfor fourdifferent fluids (water, Butanol, Syltherm800, Ethylene
Glycol)whichcorrespond to thePrandtl, ReynoldsandGrashof numberswhich arecalculatedfrom
thetemperature entrance(Pr= 8.0820, 80.5, 140, 305), (Re=143.2836, 39, 128.6, 20 ),
(Gr=257534, 102336, 47802, 9300) respectively.Theelectric intensityisconsidered I = 40
Amperes, and thegeometricaspect ratiois equal to 104.17. The results producedwere conductedsoas
to showthe influenceof the Prandtl numberonthe dynamic fieldsandtheNusselt numberinforced
convectionmodes(Gr =0)andmixed convection. An empirical correlationexpressing theNusselt
numberdepending onthenumber ofthePrandtl and thenumber of theRichardson Numoy = f (Pr, Ri),Numoy=19.543 * Ri 0.1598* Pr - 0.0539
