MAXIMUM ALLOWABLE THERMAL STRESSES CALCULATION OF WATER TUBE BOILER DURING OPERATION

Abstract

In steam boiler industrial sector, pressure and temperature of the water tube are the two main factors that affecting the safety and efficiency of a steam boiler. Explosions may be occurring because of a sudden drop in pressure without a corresponding drop in temperature. Therefore, understanding the temperature distribution of the water tube boiler is essential control the failure and explosion of the boiler. Once the temperature distribution is known then the limiting factors that affect the water tube life such as maximum allowable thermal stresses can be determined. ANSYS software will be used to determine the temperature distribution in the water tube of a utility boiler during operation at elevated inlet water and furnace temperature. The theory of axisymmetric has been utilized since water- tube is cylindrical in shape. In axisymmetric theory, a three-dimensional cylindrical problem like water tube can be reduced to two dimensional by ignoring the circumferential Ө, while r-axis and z-axis became x-axis and y-axis or Cartesian coordinate. Then two-dimensional rectangular elements meshing for the profile cross-section along the water tube in r and z axes were implemented in a computerize simulation using ANSYS 10 to find out the steady state temperature distribution of the water tube.