Wang's plain-fin relations against Zhu's small-tube plate-fin air cooler
Tier 2: measurement on a controlled rig.
- What was compared
- The air-side Nusselt number and friction factor of the plain-fin relations of Wang et al. (2000) on a small-tube plate-fin air cooler of 5.15 mm tubes in seven rows, at air Reynolds numbers of 560 to 2250.
- Against
- The fits to wind-tunnel measurements with hot water in the tubes by Zhu et al. (2025, Table 2, Eq. 36 and Fig. 5b), 24 runs with a stated uncertainty of 7.47% on the Nusselt number and 6.03% on the friction factor; a measurement on a rig.
- The agreement
- Wang's Nusselt number is 18.5 to 44.4% above the measured fit (30.9% on average), the excess falling with the Reynolds number, and Wang's friction factor is 21.6 to 26.5% below it (24.6% on average). Both deviations are outside the measurement uncertainty.
- What it shows
- The cooler is outside Wang's declared domain on four of six bounds, so the case measures Wang's relations extrapolated to a small-tube coil and gives them no accuracy. It says nothing about a dry cooler's fan or plenum.
- Source
- S.-Q. Zhu, L.-B. Wang, X. Na, Z.-M. Lin, X.-E. Zhang, 'Experimental study of the condensing heat transfer characteristics in a circular tube bank fin air cooler and the comparison to a flat tube bank fin air cooler', International Journal of Heat and Mass Transfer 244 (2025) 126974Table 2 (CTBFAC geometry), section 2.3 (data reduction), Table 5 (uncertainties), Eq. 36 and Fig. 5 (the air side's fits and data span)