| At present, the electricity produced by thermal power plants, the main way of electricity production in China, basically takes up to 80% of the national electricity consumption. The chimney, the significant structure of a coal-burning power plant, is the key factor of the power plant design, construction and project control. Compared with single chimney, two or more chimneys are adopted widely in large power plants and results in more likely aerodynamic interference effects. The collapse accident of Ferry Bridge power plant occurred in 1965 is a typical example. According to the failure investigation, it was aerodynamic interference caused by the adverse consequences. So it is necessary to study aerodynamic interference of chimney group for all kinds of arrangement, which makes sense in engineering practice.By referring to the chimneys of an actual engineering, a scaled aeroelastic model of the chimney is designed and manufactured. In boundary layer flow (type B) simulated in wind tunnel, the tests are conducted for the single chimney (smooth surface) and the chimney (rough surface, equivalent higher effective Reynolds number) by measuring the mean displacement of the along wind at the top of the chimney model, observing the difference of chimney in a critical and supercritical regimes. The test results of the single chimney (rough surface) are also taken as the reference of other tests. A series of wind tunnel tests are carried out for twin chimneys with three kinds of arrangements, i.e. tandem, side by side and diagonal, and different spacing ratio L/D (L for distance between the bottom of two chimney, D for chimney bottom diameter). The mean responses are measured and compared with the ones of the single chimney.Based on the results of mean wind displacement responses, a threshold parameter of dimensionless spacing between two chimneys is proposed to assess the aerodynamic interference, which is easy to be used in the similar structure design. |
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