Compartmentalized Thermal Stress Analysis of Water-cooled Wall Tubes for Supercritical CFB Boilers
In order to ensure the normal operation of water-cooled walls of CFB(circulating fluidized bed)boilers,to avoid the occurrence of creep deformation,high temperature corrosion and other production accidents.A numerical model of the water-cooled wall temperature stress field was developed for a 600 MW supercritical CFB boiler.And the wall temperature and thermal stress analysis of the water-cooled wall zoned section in the operating condition was carried out by using the theory of thermal calculation of the furnace chamber of the zoned section and the new IAPWS-IF97 formula.The results show that the distribution of wall temperature and stress field in each section is consistent,but due to the interaction of enthalpy and high-temperature flue gas,section 5 has the highest wall temperature and the maximum thermal stress.Further analysis of the heat transfer deterioration of section 5 shows that the maximum temperature of the pipe wall is shifted,and both the wall temperature and thermal stress exceed the design value,which may lead to water-cooled tube rupture or fracture.Subsequently,for safety hazards,numerical simulation methods are used to prevent boiler heat transfer deterioration from the perspectives of reducing local heat load and controlling mass flow rate,which provides effective suggestions and means of prevention and control for the safety monitoring of the boiler.
supercritical CFB boilerpartitioned segment algorithmwater-cooled wallthermal stressdeterioration of heat trans-fer
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