The Optimization Design Of Boiler Impellor Induced Draft Fan

In boiler system, the boiler is an energy conversion device of chemical energy,electric energy consumption. And the steam which has a certain energy, thehigh-temperature water or the organic heat transfer fluid are output from it. The deviceis used for the heavy enterprises such as the thermal power station, shipping, engineand industrial and mining enterprises and so on. Therefore the boiler is an importantenergy conversion device or even a "energy equipment". But in the actual workingconditions, boiler induced-draft fan is in a relatively harsh operating conditions such asthe large granular medium like smoke dust and the unstable air current. These willcause the badly abrasion of the induced draft fan impellor and reduce the structuralperformance of the impeller greatly. And these will shorten the operating cycles ofinduced draft fan and affect the normal production of industry and agriculture seriously.Therefore it is very important to the structure optimization of the induced draft fan. Theimpeller is known as an important component and a easy to wear part of induced draftfan. So the optimized design of the impeller is made in the paper which are based uponthe research object of Wuyang cogeneration power plant’s boiler induced draft fanwhich used model AYX75-1No22D.This will improve the structure performance andoperating cycles of impeller and provide the reference for further optimization designof induced draft fan impeller and achieve the cost savings and improve economicbenefits for the enterprise.This paper has the following several main points:(1) The paper is concerned above the AYX75-1No22D boiler induced draft fanand using Pro/E to establish the three-dimensional model of the impeller and its partsaccording to the structure of the induced draft fan impeller.(2) Finite element analysis on the impeller is completed with the finite elementanalysis software ANSYS Workbench and gain the stress nephogram and the totaldeformation stress nephogram of the impeller. Comparing the analysis results with thetraditional calculation method, the shortcomings of the latter are pointed out. Two methods of calculation show that the fan impeller meet the strength conditions, but thefinite element analysis results can reflect the actual stress distributions and be moreclose to the actual situation.(3) The modal analysis of induced draft fan impeller is given by using ANSYSWorkbench and get the first six natural frequencies and corresponding mode ofvibration.And the results show that resonant frequency of the impeller is far less thanits each order natural frequency. Therefore, the impeller does not appear resonance innormal circumstances.(4) Optimal design of structure parameters(rotary table thickness,vane thickness)of the induced draft fan impellor are made using the Design Explorer module ofANSYS Workbench.The optimization results show that it can increase the vane’scompression strength, abrasion resistance ability and its operating cycles when therotary table thickness decreased near4mm, vane thickness increased2mm and the totalmass were hardly changed.And it can also make the maximum equivalent stress reducefrom163.46Mpa to157.59Mpa when the maximum total deformation was almostunchanged.Therefore,the application of parameter optimization design method in theoptimization design of boiler induced draft fan impeller can improve the structureperformance of impeller and its operating cycles effectively.