Interference effect and the working mechanism of wind loads in super-large cooling towers under typical four-tower arrangements: Fid-Bau Portal

Interference effect and the working mechanism of wind loads in super-large cooling towers under typical four-tower arrangements

Ke, Shitang / Wang, Hao / Ge, Yaojun

Abstract

AbstractGroup tower-related interference is one of the major causes of wind-induced damage of large cooling towers. The four-tower arrangements are the most common forms of the layout of group towers. In engineering practice, five arrangements are generally used, namely, single row, rectangular, rhombic, L-shaped, and oblique L-shaped. We performed wind tunnel tests on the rigid body to study the static, dynamic and extreme interference effects under these five arrangements. Then the computation formulas of interference factor that accounted for the wind directions under the five arrangements were proposed. The effects of four-tower arrangement on the distribution patterns of mean and pulsating wind pressures were discussed. The wind pressure signals at the typical measurement points of the cooling towers were subjected to decomposition and joint time-frequency analysis using mathematical statistics technique and Hilbert-Huang transform (HHT). The study shows that the maximum interference factors under the five arrangements were all higher than those under the layout of two towers. It is reasonable to use the extreme interference factor as the measure of the interference effects. The maximum positive pressure of the cooling towers was less affected by the interference effects related to four-towers, and the mean wind pressure were affected greatly in the regions of minimum negative wind pressure and leeward regions. The distribution patterns and values of pulsating wind pressures at the bottom and top of the cooling towers were significantly affected by the five arrangements of the cooling towers. Finally, based on comprehensive assessment of the interference effects of overall wind loads, arranging the four towers in a row was the best scheme, which was followed by the arrangements in oblique L-shaped pattern, L-shaped pattern, rhombic pattern and rectangular pattern successively.

Highlights•The wind tunnel test of five typical four-tower arrangements (e.g. in a row, rectangular, rhombic, in L-shaped and oblique L-shaped pattern) was carried out.•The effects of four-tower arrangement on the distribution patterns of mean, pulsating and extreme aerodynamic loads were discussed.•The typical wind pressure signals were subjected to decomposition and joint time-frequency analysis using mathematical statistics technique and HHT.•The best scheme and the arrangements optimization for the four-tower pattern were provided.