
Conductive sublayer of turbulent heat transfer for heating of water in a circular tubeConductive sublayer of turbulent heat transfer for heating of water in a circular tube 
"/Hata, Koichi/"Hata, Koichi ,
"/Fukuda, Katsuya/"Fukuda, Katsuya ,
"/Masuzaki, Suguru/"Masuzaki, Suguru
53
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8
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, pp.2559

2576 , 201708 , Springer Verlag
ISSN:0947741114321181
Description
The steadystate and transient turbulent heat transfer coefficients in circular platinum (Pt) test tubes (inner diameters: 3 and 6 mm; heated lengths: 66.5 and 100 mm and 69.6 mm, respectively) were systematically measured using an experimental water loop for a wide range of flow velocities, inlet liquid temperatures, Prandtl numbers, inlet pressures, and exponentially increasing heat inputs (Q (0) exp(t/tau), tau: exponential period). The Reynoldsaveraged NavierStokes equations and the kepsilon turbulence model for unsteady turbulent heat transfer in circular test sections were numerically solved for heating of water with heated sections of diameter 3 and 6 mm and length 67 and 100 mm and 70 mm, respectively, by using computational fluid dynamics code under the same conditions as those in the experiment and with temperaturedependent thermophysical fluid properties. The thickness of the conductive sublayer, delta (CSL,st) and delta (CSL) [=(Delta r) (out) /2], and the nondimensional thickness of the conductive sublayer, (y (CSL,st) (+) ) (TEM) [=(f (F) /2)(0.5) rho (l) u delta (CSL,st) /mu (l) ] and (y (CSL) (+) ) (TEM) [=(f (F) /2)(0.5) rho (l) u delta (CSL) /mu (l) ], for steadystate and transient turbulent heat transfer at various heated lengthtoinner diameter ratios, inlet liquid temperatures, and exponential periods were measured on the basis of the numerical solutions. The correlations of the thickness of the conductive sublayer, delta (CSL,st) , and nondimensional thickness of the conductive sublayer, (y (CSL,st) (+) ) (TEM) , for steadystate turbulent heat transfer and those of the thickness of the conductive sublayer, delta (CSL) , and nondimensional thickness of the conductive sublayer, (y (CSL) (+) ) (TEM) , for transient turbulent heat transfer in a circular tube were derived.
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