Numerical Simulation of Air Purge in the Induced Draft Fan
|School||North China Electric Power University|
|Course||Thermal Power Engineering|
|Keywords||centrifugal fan numerical simulation gas-solid flow air purge|
Centrifugal fan is widely used in all aspects of industrial production, mechanical energy is changed into pressure energy and kinetic energy. The Fan of the power plants for the transmission and emission of dust-containing flue gas, due to the impact of flue gas which contains dust particles, the impeller will have the problem of dust collisions and wear, which will cause friction and ash deposition on the leaf. Because of the gathering of dust on the leaves, the aerodynamic performance becomes poor, efficiency reduces, energy consumption increases, vibration enhances, and even causes accidents. So researching on the movement of the ash particles, and the method of reducing the ash deposition, is important to the safe and economic operation of the fan.Based on computational fluid dynamics (CFD), using the method of numerical simulation to study the movement of the fluid, can combine theoretical analysis and practical research together, and is simple and accurate. So this paper uses numerical simulation to study the fouling and ash cleaning inside the fan, which has some practical significance to the problem of cleaning.Firstly, do the modeling, meshing and boundary condition setting of Y4-73Boiler Fan within the Gambit. Then, based on the three-dimensional N-S equations and RNG κ-ε two-equation turbulence model, and using the SIMPLE algorithm, imports into Fluent and has turbulent flow field numerical simulation, so to get the movement of the flow field in the fan. Then add the jet source of dispersed phase at the inlet, using the particle trajectory model to track the trajectory of solid particles, and get their movement patterns and distribution. And thus analysis the reasons for wear and fouling of the blades from theoretical, with the fouling situation of the fan site, so to explore the mechanism and impact factors of fouling of the leaf blade.Combining with the jet theory and field conditions, and the existing cleaning technologies, and considering the requirements of the fan flow, add purge gas flow within the fan using the nozzle, do the simulation of it on the basis of the gas-solid flow, so to get the conditions of the flow field and the changes of particle trajectory in the fan, and provide a theoretical reference for the air force blowing for the impeller cleaning.