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| {\rm Nu}=3.66 + \frac{ 0.065 \cdot {\rm Re} \cdot {\rm Pr} \cdot {D/L} }{ 1 + 0.04 \cdot ({\rm Re} \cdot {\rm Pr} \cdot {D/L})^{2/3} } |
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Laminar flow in pipeline with diameter and length . |
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| {\rm Nu}=0.023 \cdot \mbox{Re}_D^{3/4} \cdot \mbox{Pr}^{0.4} |
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Turbulent flow in pipeline LaTeX Math Inline |
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body | --uriencoded--\mbox%7BRe%7D \geq 10,000 |
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| {\rm Nu}=\frac{ (f/8) \, ({\rm Re} - 1000) {\rm Pr} }{ 1 + 12.7 \, (f/8)^{1/2} \, ({\rm Pr}^{2/3} -1) } |
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body | --uriencoded--%7B\displaystyle 3000\leq \mathrm %7BRe%7D\leq 5\cdot 10%5e%7B6%7D%7D |
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body | --uriencoded--0.5\leq \mathrm %7BPr%7D \leq 2000 |
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| is Darcy friction factor |
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| {\rm Nu}=0.3 + \frac{0.62 \, \mbox{Re}^{1/2} \, \mbox{Pr}^{1/3} }
{\left[ 1+ (0.4/\mbox{Pr})^{2/3} \right]^{1/4}}
\left[ 1 + \left( \frac{\mbox{Re}}{282000} \right)^{5/8}\right]^{4/5} |
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body | --uriencoded--\mbox %7BRe%7D \cdot \mbox %7BPr%7D \geq 0.2 |
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Accuracy LaTeX Math Inline |
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body | --uriencoded--\sim 20 \%25 |
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Relation to Bio number
The real difference betweeh the two are;
Nusselt number confirms whether conductive or convective heat transfer dominates across the fluid-solid interface while Biot number, whether significant thermal gradients will develop inside a solid by the ratio of heat transfer away from the surface of a solid to heat transfer within the solid.
See also
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Physics / Thermodynamics / Heat Transfer
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[ Prandtl number ] [ Rayleigh number ] [ Reynolds number ] [ Biot Number ]
References
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