Numerical Study On Induced Draft Fan Vibration Caused By Accumulated Dust Behind Water-film Desulfurization Dust Catcher

In our country, integrated desulfurization and dedusting device is often used inmedium and small sized coal-fired boilers, the more common one is the water-filmdesulfurization dust catcher. Behind it is induced draft fan.Because the smokecontains dust particles, induced draft fan blades will have dust depositionphenomenon which can make the dynamic-equilibrium of the induced draft fanimpeller poor. It will cause the impeller imbalance and vibration when the imbalancereaches a serious degree, which seriously affects the normal running of the induceddraft fan. This paper studies the internal flow field distribution of the induced draftfan and designs the blowing device to reduce and prevent the occurrence of heavyvibration, which has great significance on the safe and economic running of theinduced draft fan.First, it builds up the3D model of the induced drafr fan and meshes the grid withGambit. Secondly, it simulates the internal flow field of the induced drafr fan underdifferent load conditions by Fluent, analyses the internal pressure distribution andvelocity distribution of the induced draft fan, and then makes detail analysis of the fanblades alone to fine out the relationship of the internal flow field and heavy vibration.Finally, it simulates the blowing effect of the sand flow by Lagrangian particle trackmodel, finds out the sand factor of the better scavenging effect and the unseriousweared blade, makes a decomposition on the scavenging process of a blade, and thenit proved that the venting device which can realize the continuous and efficientpurging and that has unaffected running on the induced draft fan.Because the induced draft fan used widely in industry, it leads to many factors ofthe dust deposition, so the blowing device should keep pace with time and adapt tothe actual production continually. Therefore, this paper also considers the problemsunder the condition of the sand quantity increased heavily when the blowing device are deposited heavily, and proposeds the suggestion of improvement on the shape ofthe nozzle, which has a reference significance on the updates of the blowing device.