Experimental And Numerical Study On The Flue Gas Velocity Deviation In 600MW Unite Boiler Model

The development of electric power have an influence on the development of the national economy directly, Tangential firing boiler is main type of burn way in our country power station boiler. In power plant , safety and economy have been the targets that the electric power profession persue, Gas temperature deviation, that is, non-uniform gas temperature distribution, has been a long time problem in tangentially fired furnace that sometimes results in pipe explosion of super-heaters and re-heaters. Research of this kind of burning way boiler has very far-reaching meaning . There are a lot of factors that influence the flue gas imbalance , mainly includes in –boiler process and in –furnace process. as for in-boiler process, influencing steam temperature deviation is as follows, heat-absorption deviation, flow deviation, structure deviation, and inlet flue steam temperature deviation; In furnace process ,many experts thought that residual swirl in furnace outlet is the root cause of flue gas velocity deviation, an flue gas corridor aggravates velocity deviation in flue gas channel. The contents of this thesis include :Analyzing the gas flow velocity distribution in the horizontal flue and the influencing factors, how to reduce the impact on boiler of the imbalance. Based on the experimental platform according to the proportion of 1:20 for the 600MW unit boiler ,this paper did a thoroughly research in the upper part of the furnace ,adopting methods of simulating tests in cold condition combined with the numerical simulation of the turbulence fluid of the gas fluid .The distribution of the gas velocity in the outlet of the furnace was obtained through the cold condition simulating test .The result of the test was consistent with the result of numerical simulation very well .This shows that numerical method is viable to the tangentially fired boiler using the commercial software FLUENT . Research indicated that the reverse swirl air can effectively weaken residual swirl at furnace and then decrease flue gas imbalance in horizontal gas –pass to a certain extent ,reducing suitably the supposed diameter can decrease flue gas imbalance, the optimum arch structure, such as lengthening its altitude ,changing angel depth ,may obviously meliorate non –uniformity of flow field in flue gas channel ,increasing chamber altitude can lengthen the weaken course , the specific screen arrangement of heating surface can accelerate its weaken .