Nu = 0.023 Re⁰·⁸ Prⁿ — standard correlation for turbulent forced convection in smooth pipes. Results are shown alongside the more accurate Gnielinski correlation for comparison.
Heat Transfer · Pipe ConvectionHeat transfer direction (sets Pr exponent n):
Fluid preset (fills Re, Pr, k):
Valid range: Re > 10 000 (turbulent, fully developed)
Valid range: 0.6 ≤ Pr ≤ 160 · Air ≈ 0.71 · Water ≈ 7
Dittus-Boelter correlation:
Gnielinski correlation (more accurate):
Gnielinski is preferred for design work — it covers the transitional regime and gives ±10% accuracy vs ±25% for Dittus-Boelter, particularly at moderate Re.
Correlation comparison:
| Correlation | Re range | Pr range | Accuracy |
|---|---|---|---|
| Dittus-Boelter | > 10 000 | 0.6 – 160 | ±25% |
| Gnielinski | 3 000 – 5×10⁶ | 0.5 – 2 000 | ±10% |
| Sieder-Tate | > 10 000 | 0.7 – 16 700 | ±20% (high ΔT) |
| Petukhov | 10⁴ – 5×10⁶ | 0.5 – 2 000 | ±6% |
From Nu to heat transfer coefficient h: