Kröger Example 9.3.1
The six-bay bank under a 3 m/s crosswind
Tier T: a textbook worked example - a published answer, not a measurement.
- What was compared
- The heat transfer rate of the six-bay forced-draft bank of Kröger's Example 8.3.1 under a crosswind of 3 m/s at 5.7 m across its long axis, with the mean fan flow ratio and the recirculation effectiveness under that wind.
- Against
- Kröger's worked Example 9.3.1 (Kröger, Vol. 2, Section 9.3), which reads its factors from the CFD study of Duvenhage and Kröger (1996); a published calculation and not a measurement.
- The agreement
- The model gives a mean fan flow ratio of 0.917 against Kröger's 0.9 and a recirculation effectiveness of 0.967 against his 0.97, and the heat transfer rate of the bank comes out 1.5% above his 65.355 MW. The differences are Kröger's rounding of his figure readings, and every row lies within its tolerance: 2% on the heat transfer rate, 3% on the flow ratio and 1% on the effectiveness.
- What it shows
- The agreement verifies that the model implements Kröger's crosswind procedure for a fan-driven bank, reading the factors of Duvenhage and Kröger as he does. The factors come from a CFD study of a smaller bank applied beyond its range, and the case says nothing about the procedure's accuracy against a measured bank.
- Source
- Kröger, D.G., Air-Cooled Heat Exchangers and Cooling Towers: Thermal-Flow Performance Evaluation and Design (PennWell, 2004)Vol. 2, Example 9.3.1 (extending Example 8.3.1), Figs. 9.3.6-9.3.11 after Duvenhage and Kröger (1996)