The Research On The Pulse Cleaning Of The Bag Filter With Unsteady Numerical Simulation And Performance Optimization

Pulse-jet cleaning in bag filter is a filter regeneration process, its performance is related to energy conservation and emission reduction efficiency directly. However, due to the characteristic of short time, many influence factors and high-speed, compressible and fast variational gas flow in the cleaning process, there is no definite conclusion on cleaning mechanisms. Meanwhile,it is difficult to find mathematical equations to describe the random deformation of flexible filter bag under the action of dust cleaning gas flow. In limited literature, numerical simulation method on cleaning process was implemented, but nearly all filter bags have been conducted as rigid medium, which was supposed not to expand and contract, there was a certain gap compared with engineering practice.Based on theories such as fluid dynamics, thermodynamics, elastic mechanics and so on, unsteady numerical simulation and computational structural dynamics(CSD) were implemented on analysis on the impact of related factors on nozzle velocity, pressure distribution, and maximum deformation of filter bags as the cleaning performance and injection eccentric angles and flow rate distribution for each nozzle of injection pipe as possibility of filter bag breakage. Then in-depth inquire into pulse-jet cleaning rules and mechanisms in bag filter, and realize its overall accurate evaluation of comprehensive performance. The main research contents and achivements were as follows:(1) According to the problem that it is very difficult to measure the pressure and velocity on the nozzle of injection pipe, the unsteady numerical simulation method to in-depth study many composite structure of injection pipe and nozzle in practical engineering was conducted. Then better combination scheme can be obtained.(2) In most literature, filter bag was conducted as rigid medium to study the cleaning process by numerical simulation. Coupling calculating method CFD/CSD was implemented on researching on the impact related factors on cleaning performance, which can provide reference for the optimization design of cleaning device. (3)The study of weather enclosure drainage influence on dust cleaning performance showed that net gas chamber drainage was beneficial for filter bag to produce greater deformation and shorten the time when maximum deformation appeared; Venturi tube was benificial to strengthen drainage, so as to obtain much more cleaning power, and it was found that cleaning performance with external venturi tube was better than built-in one.(4) All parametric design for model and condition was implemented, which can provide technical foundation for simulation design & analysis platform of the whole series products under different conditons.