Study On Wind Load Characteristic Of Large HyPerbolic Cooling Tower

Hyperbolic cooling tower as a huge structure is widely used in power plants and nuclear power stations for circulating water cooling. Its height is getting higher and higher with the rapid development of the electric power, even exceeding the limiting value 165 m in China’s present cooling tower design code. Along with the extension of power plant and the increase of unit quantity, the quantity of cooling towers are becoming more and more too. Due to its large body and thin shells, wind load is the dominant load for design. It is necessary to determine the distribution of wind load on the surface and the interference effect among towers, so we can find out the approaches for wind resistance to ensure the safety and economy of this huge structure. The main research contents of this study include:(1) Firstly, a hyperbolic cooling tower is studied in whole size via the method of numerical simulation CFD, the height of which is 115 meters. The mean wind pressure coefficient of both cooling towers with smooth surface and cooling towers with different roughness heights are simulated. The results of simulation, the result of related specifications and the field test data measured by Xi’an Institute of Heat Engineering are compared. The results show that the numerical simulation CFD of cooling towers in whole size has solved the problems of Reynolds analogue criterion.The mean wind pressure coefficient of cooling towers with smooth surface is far away from the actual value. So the roughness height on the surface of cooling towers must be considered.(2) The wind tunnel test of Measuring Pressure a cooling tower model with different roughness wallpapers on their throat region is conducted to verify the reliability of numerical method. The model scale factor of the model is 1/150. The results of different conditions, the result of related specifications and the field test data measured by Xi’an Institute of Heat Engineering are compared. The target wallpaper is chosen through the comparison. Then the wind tunnel test of the whole cooling tower model with this target wallpaper is conducted. The test results arestudied deeply and are compared with the results of simulation before. The results show that the least mean wind pressure coefficient appears in the throat position along the radial direction of the cooling tower. The drag coefficient has exceeded the result of related specifications and the ends of the drag coefficient curve are larger than the middle. The same law is obtained by the two methods, and the reliability of numerical method is verified too.(3) One and four hyperbolic cooling towers in “L” type are both studied in whole size via the method of numerical simulation CFD, the height of which is 175 meters.The aerodynamic characteristics and external characteristics of the flow around are both studied. At last, these results of large cooling tower and each one of the four towers are obtained, which include the mean wind pressure coefficient and the Variation of the drag coefficient along the radial direction of the cooling tower. It is meaningful not only to the reasonable design of the practical engineering in wind resistance, but to the further improvement on related specifications.