Simulation Analysis And Management Of Large Deformation Of W Type Flame Boiler Water Wall

Based on the situation of large deformation of the front wall of 600MW "W" Flame Boiler in a Thermoelectric Corporation,the thermal analysis,stability analysis and combustion analysis were carried out by using the finite element method.According to the analysis results,the factors that lead to the deformation of the water wall are summarized,and some reasonable suggestions are put forward,which has practical significance for the safe and stable operation of the boiler.Firstly,using the APDL program method,the two-dimensional finite element numerical model of water wall was established by ANSYS software to analyze the temperature distribution law of water wall in three conditions:No scale,outer wall scaling and inner wall scaling.The difference of temperature distribution under three conditions is compared.The results show that the temperature will increase significantly in the case of inner wall scaling.Furthermore,the three-dimensional model of water wall was established.The temperature,deformation and stress distribution were analyzed under three conditions after simplifying the model and boundary conditions.The results of the temperature field agree well with the two-dimensional model.The inner wall scaling is the main factor that causes the water wall tube overheating.The results of deformation analysis show that the scaling of the inner wall will hinder the thermal deformation of the furnace wall,and the deformation of the vertical direction of the furnace wall will also increase significantly.The results of stress analysis show that the scaling of the inner wall will increase the stress in the area of the scale and cause the stress of the area above the scale layer to increase.The eigenvalue buckling analysis of the furnace wall under three conditions is carried out based on the analysis of thermal stress.Compared with the non-scaling condition,the stability coefficient and mode don't change obviously in the condition of external wall scaling.When the inner wall is scaling,the stability coefficient is reduced,and the instability mode is different.Combined with the results of previous thermal analysis,it is indicated that the possibility of deformation of the water wall is caused by inner wall scaling,so the water wall needs descaling.Finally,combustion simulation was carried out by fluent software.By analyzing the temperature field,velocity field and excess air coefficient distribution in the furnace,it is found that the combustion center is higher,and the air distribution ratio needs to be adjusted.Some reasonable suggestions are put forward to increase the air inlet velocity according to the problem.The analysis methods and conclusions of this paper provide a reference for solving similar problems in power plant boilers.