Numerical Simulation Study Of Wind Load On Large Hyperbolic Cooling Tower

Large air funnel cooling tower usually formed by thin and elastic hyperbolic shells is an important cooling equipment in thermal power station. Due to its large body, complex shape and thin shells, this kind of structure is sensitive to wind load which is the dominant load for design. It is necessary to determine the distribution of wind load on the surface and the interference effect between towers, so we can find out the approaches for wind resistance.In this paper, numerical simulation method was employed to study the distribution of wind-induced pressure both on the inner surface and the outside surface of a single tower, the distribution of pressure on the inner surface induced by natural convection, airflow interference between double towers and among three towers, and the flow feature for circle section with different superficial roughness. Firstly, the fundamental turbulent flow equations on the basis of the Navier-Stokes Equations and the k-εturbulence models, numerical discretization and the solution method are anlyzed, then the flow field of single tower model is computed and the result is compared with that of the code in order to validate the availability and rationality of numerical simulation. On the basis of the research of single tower, the interference effects between double towers and among three towers via computing and obtaining the average wind pressure for the fixed distance towers under various wind directions are anlyzed. In the end, the effects of various superficial roughness on the circle section and the distribution of pressure on the inner surface induced by natural convection are studied. Three different regions according to different wind azimuths are classified. According to the analysis of the distance among towers, the drag coefficient under various wind directions and the average wind pressure, the zero wind azimuth is the most disadvantage under the condition of fixed distance between double towers. The worst interference effect occurs when the distance between double towers is shorter than 1.5 diameter of the cooling tower under the condition of zero wind azimuth, to which we should pay attention. Under the condition of ninety wind azimuth, the block effects to the tower behind present three phases and disappear after the distance beyond 5.0 diameter of the cooling tower. By changing the amount, width and length of the ribs, the influence to the flow feature outside of the circle section is studied. Establishing multiphase flow natural convection model of the cooling tower, it is found that the pressure induced by natural convection on the inner surface can be ignored. All the above research is meaning to establish rational and useful engineering method and constitute correlative codes and regulations.