Numerical Simulation Of Steam Flowing And Heat Transferring In A Superheater Of Certain Marine Boiler

Superheater is one important part of boiler setting, As a result of its bad working condition, accidents of overheating and bursting of tubes often occur. It is an emphasis to study superheater at all times. Brief analyses are made about the working condition and mechanism of overheating and bursting of the superheater in this thesis. We carry on an investigation into the superheater of certain marine boiler, build an appropriate geometry model and simulate it by adopting software FLUENT.It is difficult to simulate the all and the one, because of the large whole structure of the superheater. To reduce the size of the superheater by using reasonable scale on the base of original model and the simulant results can reflect the working characteristic of the original superheater.The rule of the various parameters'distributing are studied when the steam-gas is flowing in the inner of header and transferring heat by using Realizable k-s model, SIMPLEC arithmetic of the coupling of pressure and velocity, standard wall function near the wall and concealed format dispersing governing functions in this thesis.Three different instances are done in this numerical simulation of the superheater that is uniform distribution, uniform descending and uniform increasing of thermal load along the direction of steam flow. Through numerical simulation, the distribution nephogram of pressure, temperature and enthalpy has been gained, and also the mass flux in the tubes and various parameters of the steams in the tubes that are intercepted by sections. Then the simulation results have been analyzed.It makes known that the rules of distribution of static pressure are decided by the structures of the header, through three different numerical simulations. We can regard the superheater as two z structures in series with each other from the results of simulations. The second z structure is not as good as the first one along the direction of steam flow But the non homogeneity of fluxes have some reduces. The arrangement of the superheater is compact, and makes reparation of the single z structure. Numerical simulation can be used for providing reference plans for optimizing the safe and economical operation of superheater, at the same time it can economize large numbers of manpower and material resources. Numerical simulation methods would be extensively applied to boiler operations safely in the future.