Zhao's Heller tower under crosswind at constant load
A third family, and a third multiplier
Tier 3: CFD, co-simulation or another model.
System: Indirect dry cooling, natural draft, vertical bundles
- What was compared
- The rise in the water entry temperature of a 172 m indirect natural-draft dry cooling tower with vertical delta radiators, held at a heat load of 870.1 MW under a crosswind of 0 to 20 m/s, on Kröger's crosswind method as printed.
- Against
- The CFD study of the same tower by Zhao et al. (2015, Section 4.2 and Fig. 10), whose CFD was validated against a scale model of the radiator annulus; another model and not a measurement on the tower.
- The agreement
- The model under-predicts the rise by 2.2 to 3.2 K up to 8 m/s, about a quarter of a 5 to 12 K rise, comes within 0.3 to 1.2 K at 12 and 16 m/s, and over-predicts by 1.7 K at 20 m/s, where the CFD recovers. A multiplier of 1.48 on the crosswind pressure coefficients reproduces the rise from 2 to 8 m/s to 0.88 K RMS.
- What it shows
- The case measures how far Kröger's crosswind method, fitted on horizontal bundles, departs from one CFD study of a ring of vertical deltas, and it carries no model-form uncertainty. Its multiplier of 1.48 differs from those of the other two CFD families (0.3 to 0.6 and 1.1 to 1.2), and no tower ratio in the catalogue orders the three.
- Source
- Y. Zhao, F. Sun, Y. Li, G. Long, Z. Yang, 'Numerical study on the cooling performance of natural draft dry cooling tower with vertical delta radiators under constant heat load', Applied Energy 149 (2015) 225-237Section 2 (the tower and its radiators), Eqs. (5) and (8), section 3.6 (the profile index), section 4.2 and Fig. 10 (the water entry and exit temperatures against crosswind at the rated load)