Kröger's crosswind method on Kong's two delta rings, 3 to 15 m/s
Tier 3: CFD, co-simulation or another model.
- What was compared
- The ratio of the heat transfer rate under wind to its windless value, Q/Q0, of two natural-draft direct dry-cooling towers with vertical rings of deltas (a 60° triangular and a 180° annular arrangement), at winds of 3 to 15 m/s, with Kröger's crosswind method as printed.
- Against
- The CFD study of Kong et al. (2018, Table 3), which tabulates the air flow and the heat transfer rate per sector at each wind speed; it is a second model and not a measurement.
- The agreement
- As printed, the method over-predicts the effect of wind about twofold: the model's Q/Q0 lies 8.9 and 5.8 points below the CFD's at 6 m/s on the two rings, and 23.1 and 16.9 points below at 15 m/s. A single multiplier on the pressure coefficients (0.41 and 0.58) reproduces each series to 1.4 and 1.9 points RMS.
- What it shows
- The case shows that the dependence of Kröger's crosswind method on wind speed carries over to a vertical ring of deltas and that its magnitude does not. Fitted on the air flow, the same comparison gives multipliers of 0.46 and 0.55 and is part of the basis of the product's default of 0.5 on a vertical ring.
- Source
- Y. Kong, W. Wang, X. Huang, L. Yang, X. Du, 'Annularly arranged air-cooled condenser to improve cooling efficiency of natural draft direct dry cooling system', International Journal of Heat and Mass Transfer 118 (2018) 587-601Table 3 (per-sector air flow and heat rejection at 0-15 m/s), Eq. (8) (the wind profile, 10 m reference, exponent 0.2)