Parametric Analysis of Hyperbolic Cooling Tower under Seismic Loads, Wind Loads and Dead Load through Staad. Pro
Abstract
Hyperbolic cooling towers are large, thin shell reinforced concrete structures which contribute to environmental protection and to power generation efficiency and reliability. The safety of hyperbolic cooling towers is important to the continuous operation of a power plant. It is observed from the analysis that maximum displacement, support reactions, support moments, stresses and bending moments in plates due to seismic loading, wind loading and dead load i.e. its self weight on a hyperbolic cooling tower is continuous function of geometry (top diameter, throat diameter and height). Earthquake zone plays the important role in analysis. So from this work it can be observed that 300 mm thickness, throat diameter 60m and height 250m is much efficient among all but if height is mandatory to extent than height should not be more than 159m (height taken from actual work) and 170 m height is critical.
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Introduction
Cooling tower is a tall cylindrical concrete tower used for cooling water or condensing steam from an industrial process. It is a heat rejection device which extracts waste heat to the atmosphere through the cooling of a water stream to a lower temperature. It is generally of 2 shapes, hyperboloid or hyperbolic and rectangular. Hyperboloid cooling towers will be around 130-200m tall and 100 mm in diameter while the rectangular cooling towers will be around 40m tall and 80m long. Cooling tower is generally made of concrete and rebar. The type of foundation required for each cooling tower, e.g. individual foundations, ring foundation or piling, is determined according to the ground conditions. Applications of cooling tower include Oil refineries, petrochemical and other chemical plants, thermal power stations and HVAC systems for cooling buildings. The safety of hyperbolic cooling towers is important to the continuous operation of a power plant. Depending upon the site, earthquake may govern the design of the tower.
Conclusion
From the analysis results, it can be concluded that
The nodal displacement of the structure increases by 30% as the height of the Cooling tower is increased while the nodal displacement can be reduced by around 20-25 % by increasing the thickness of the plate used for modelling the cooling tower.
Mass participation of more than 75% is obtained for all the dominant modes.
The variation in plate stress was found to be minimum (5%) with the increase in height of the model and thickness of the plate. The CQC shear of the increased by around 35% as the height of the tower and thickness of the plate is increased.
From the above results taking cost effectiveness into consideration, the optimum height for a cooling tower can be considered as 250m, optimum plate thickness as 300mm and optimum throat diameter as 60m.