| With the rapid development of China’s economy,energy consumption and environmental pollution have become major challenges facing us.In order to reduce the "wet smoke plume"generated when the boiler emits flue gas,in recent years,with the advocacy of relevant departments and the support of enterprises,many power plants have carried out renovation projects to install smoke plume removal equipment.However,due to the large number of equipment and the large space occupied,the flue flow field is not uniform,which not only affects the efficiency of the installed equipment,but also causes problems such as wear and leakage of the flue due to scouring.And the problem must be solved.This article relies on the actual engineering project of a certain thermal power plant in Shaanxi Province,and optimizes the design of the flue duct from the boiler tail to the dust collector section based on the data obtained from the field survey,measurement and initial design data.This section of flue is equipped with a flue gas cooler,and the installation space is relatively compact,so the uniformity of the flue flow field is difficult to meet.Therefore,the uniformity of the flue flow field is difficult to be satisfied.Therefore,this article uses Fluent software for physical modeling and numerical simulation of the pipe section.First,by changing the form of the flue bend,the suitable bend plan for this project is selected.Then,by changing the installation method of the deflectors and whether the inlet and outlet of the bend are changed,a further optimization analysis is made to determine the most suitable flue scheme for this project.Finally,the scheme is verified by simulating different flue gas inlet speeds.The research results show that the flow field distribution of the round bend in the four bend forms is relatively uniform.The deviation coefficients of the velocity distribution of the 45 °section of the two bends and the section of the equipment inlet section have reached 17.6%,20.2%and 15.2%,with high optimization potential;Through simulation analysis of the influence of the installation method and number of deflectors on the flue flow field,it was found that when the three deflectors are unevenly distributed in the round bend,the pressure drop of the flue main pipe section and the equipment section is the smallest,and the flow field is uniform good performance,which is conducive to saving energy and reducing the erosion and wear of the deflectors by the flue gas;Compared with the scheme that the inlet and outlet of the bend are not installed with a reduced diameter,the flow field pressure and velocity distribution inside the bend with a reduced diameter is significantly reduced,which suppresses the occurrence of secondary flow and can effectively reduce the wear of the bend;In order to reduce the structural resistance caused by the excessive length of the deflectors,the inner and outer radius of the bend are adjusted to reduce the pressure loss generated at the bend;Finally,the deviation coefficients of the velocity distribution of the three research sections of the selected flue scheme are 9.7%,12.7%and 8.3%,which fully meet the specifications.When the boiler bears different loads,it has different flue inlet speeds.After verification,this scheme can still meet the requirements.This article provides technical support and theoretical guidance for the optimization of the homogeneity of complex flues in the transformation of such engineering projects.The research methods and conclusions can be used for similar engineering projects as a reference. |
