EFFECT OF VARIOUS DESIGN PARAMETERS OF CHIMNEY UNDER WIND LOAD

Abstract

This thesis investigates the impact of wind on high-rise chimneys, focusing on predicting wind loads and analysing the effects of varying chimney dimensions. Using computational fluid dynamics (CFD) simulations, the study considers variables such as wind speed, direction, turbulence, chimney shape, size, and parameter variations. Simulations were conducted using ANSYS CFX 2022 R2 and AutoCAD, covering wind incidence angles from 0 to 180 degrees. Pressure contours and coefficient of pressure (Cp) values were analysed to understand pressure distribution and wind-induced forces. Results showed that pressure values varied with wind angle, predominantly exhibiting suction forces. Cp values were consistently negative, indicating the presence of suction forces. The findings highlight the influence of wind angle on chimney pressures, with a decrease in suction forces as the wind deviates from perpendicular. Wind velocity affects pressure variations, with higher velocities leading to intensified positive and negative pressures. Different wind zones result in varying pressure distributions, from laminar flow in low velocity regions to turbulent flow in higher wind zones. The study also explores the impact of chimney dimensions. Larger top diameters promote smoother flow transitions, reduced pressure drop, and improved flow efficiency. Smaller top diameters may cause increased turbulence and pressure fluctuations. Base diameter variations affect flow separation, windward flow deflection, and wind pressure distribution. Chimney height influences flow dynamics, with taller chimneys exhibiting more pronounced upward airflow. Chimney wall thickness affects streamlines' coherence, with thicker walls promoting laminar flow and thinner walls causing turbulence.