Numerical Investigation On Mean Wind Loads For Interference Of Twin Chimney Stacks

Chimney stacks are the significant structures for a thermal power plant, they have the characteristics of great height and large investment, and they play a major role in controlling power plant design, construction and construction schedule. China has built a number of thermal power plant, wherein the height of chimney stacks are more than200meters. Layout of chimney stacks are generally for both two side by side, it may lead to significant aerodynamic interference effects. For example, when the two chimneys are in tandem arrangement, the aerodynamic interference between the upwind chimney and the downwind chimney will become the main control factor of the chimney design, if one ignores this factor, it might lead to disastrous consequence.This thesis studies the aerodynamic interference effects between the two chimneys for high Reynolds number by using computational fluid dynamics software FLUENT. Since most of the chimney are similar in structure of cylinder, therefore, two-dimensional numerical simulation of flow around a chimney can be simplified as the flow around a cylinder.This thesis first briefly introduces the basic principle of computational wind engineering and the use of FLUENT software. An optimized turbulence model is chosen by conducting two-dimensional numerical simulation of flow around a cylinder and comparing the results of the single cylinder model in two Reynolds numbers and six different turbulence models. Then this thesis further studies flow around two cylinders in tandem arrangement and in side-by-side arrangement, by comparing the calculation results in two Reynolds numbers and eleven different cylindrical center distances, the changes of mean drag coefficients and mean pressure coefficients are discussed. At last, this thesis briefly introduces the wind tunnel test of the two chimneys of WPCPL4x135MW Power Plant Project, then, a three-dimensional numerical simulation is performed to study the mean wind pressure characteristics of flow around two chimneys in tandem arrangement.