The Study On Thermodynamic Properties And The Analysis Of Tube Rupture In The Superheater Of Supercharged Boiler

The superheater is the most important part of the boiler, which will directly affect thethermal efficiency and security of the entire boiler. It is of great importance to study thesuperheater. This paper takes the Supercharged Boiler General Test Stand’s superheater as themain object of study, and the check calculation of the the superheater thermodynamicproperties at the test data which based on the73Standard Calculation Method. In addition,the selection of some coefficients has been described in the paper. The results show that the73Standard Calculation Method can meet the design of the small supercharged boiler.The superheater overall1:1model is established with the Pro/E software, and dividedgird with Gambit software. The numerical simulation of flow and heat transfer at thesuperheater flue gas and steam side is taken by Fluent with the test data, and the distributionof temperature field and flow field are analyzed from the flue gas, the wall and the steam side.The results show that the relative error was within5%between the numerical simulation andtest data or the thermal calculation values of the flue gas outlet temperature and speed, thetransfer coefficient of the wall and steam outlet temperature and speed. It shows that thenumerical simulation method in the paper can well predict the superheater flow fielddistribution. By considering the heat load, the wall temperature, the steam flow in tube, theheat deviation and other factors, the most dangerous tube in superheater is the third row oftwelfth tube when running. If there is fouling on the superheater wall, the heat transferperformance will be reduced. The more fouling exists, the worse of the effect of heat transfer.The grime makes the wall temperature decreases, while the furring makes it rises.When the superheater tube cracked as overheating, the flow field will change. Thedifferent flow fields at the flue gas and steam side after the tube cracking are analyzed. It isfounded that the temperature of flue gas and steam outlet are increased, the heat transfer, heatload. The transfer coefficient and the wall temperature are also increased. The more steamleakage, the more increased. When the tube cracking occurred in the third process, the steamflow in other tubes of this process is dramatic declined. The more loss, the more decrease. Itincreases the possibility of the other tubes cracking. In addition, the steam leakage increasesthe humidity of the flue gas, and increases the dew point. This increases the possibility ofcorrosion at the flue gas outlet.