| The flue gas turbine undertakes the task of recovering the energy of flue gas.The microparticles carried by the flue gas deposit on the flue gas turbine wall surface,which can easily cause unplanned shutdown and huge economic losses.In order to accurately study the gas-solid flow characteristics in the flue gas turbine,in consideration of the entire movement process of the particles and the non-spherical characteristics of catalyst particles,the User Defined Function(UDF),including particle desorption and deposition model,is established to replace the Fluent deposition model.This paper,focuses on the desorption behavior of particles in dynamic deposition,is to study the influence of inlet flow,particle diameters,blade roughness,and particle adhesion coefficient on particle desorption.Firstly,the gas phase distribution characteristics of the flue gas turbine is simulated by using the RNG k-ε model,and then combines the particle bumpy model with the rolling desorption model and the kinetic energy deposition model to track the entire trajectory of particles.Grid independence and turbulence model independence ensure the correctness of the Fluent calculation scheme.Secondly,this paper studies the effects of different inlet flow rates and different blade roughness on the gas phase flow field,desorption mass flow rate,and desorption rate.Increased flue gas velocity strengthen the velocity gradient of the near-wall fluid.Because the high shear stress promotes the desorption of the initially adhered particles,so the particle desorption mass flow rate keeps increasing.As the flow rate increases,the frequency of particle collisions with blades per unit time and the catalyst concentration near the wall increase,which promotes particle deposition.The increase of inlet flow leads to a higher proportion of initially adhered particles desorption.With the increase of wall surface roughness,the particle desorption mass flow rate and desorption rate of the static blade’s suction surface and the rotating blade surface first decrease and then increase,and the deposition mass flow rate first increases and then decreases.The desorption mass flow rate of the static blade’s pressure surface changes as "Wave" shape,the deposition mass flow first increases and then decreases,while the desorption rate shows an "increase-decrease-increase" change.At last,The effect of particle size and adhesion coefficient on particle desorption are studied.Particles below 1μm cannot be desorbed by the static blade and the rotating blade,with the increase of particle diameter,the desorption mass flow rate gradually decreases,but the desorption rate increases rapidly.The particle desorption area of the static blade is at the rear end and gradually increases,except for the 1-3μm particle desorption area of the static blade’s suction on the side of the central hub;the particle desorption area of the rotating blade’s pressure surface increases from the front and rear edges to the entire pressure surface,and then the area slowly decreases;the desorption area of the suction surface of the rotating blade is concentrated on the side of the hub and there is a tendency to shift in the middle of the blade.When the particle adhesion coefficient increases,the particle desorption mass flow rate increases and the desorption rate decreases. |
