Numerical Simulation Of The Process Of The Pulse Cleaning Of Injection Pipe Of Entrained Type With Velocity Difference

After several decades of development, the pulse bag filters have been used in dedusting field widely. This technology is becoming more and more mature, but there still exists many problems, such as the technology of filter media is not good enough, the airflow organization is uneven, the design of dust-cleaning is unreasonable and the pulse tube installation does not reach the designated position. The poor dust-cleaning technology or poor regeneration of the filter bag and the difficult to remove the dust covered or penetrated into the fiber layer result in filtration performance fell sharply and the running resistance of the system is too large. Above these will affect the system's security and normal operation. Therefore, the study of the cleaning system of bag filter plays an important role in optimal design and ensuring the using life of filter media.This article relies on the National High Technology Research and Development Program "Research on Key Technology of Removal Fine Particles and Heavy Method" and a Invention and Patent:a Method of pulse cleaning injection pipe of entrained type with velocity difference. This article uses the Gambit software to mode geometric and a relatively mature computational fluid dynamics software FLUENT to make the numerical simulation. Then it analysis the feasibility of the pulse cleaning injection pipe of entrained type with velocity difference in the design and debug and calculate various parameters of the model. It finds out the factors which influence the cleaning ability and provides theory basis for cleaning system of pulse bag filters, which can lay the foundation for future optimization of bag filter and more excellent cleaning technology.Firstly, this article studies the air-distribution uniformity and application of pulse cleaning injection pipe of entrained type with velocity difference. As the resistance of the pulse tube with the branch pipe and casing pipe is much bigger than the traditional tube, which makes the gas flow pulse pressure nosedived, static pressure increases and the dynamic pressure and static pressure of each injection differs slightly, so there is no need to adjust the diameter of the injection.Then, this article focuses on the pulse cleaning process. Through the research by induction and simplification of conditions, the high-pressure pulse cleaning process will be simplified into two-dimensional unsteady axisymmetric compressible turbulent process. It simplifies the outlet pulse jet air mass flow (flux) as a linear curve and selects theκ-ε numerical model. Through the simulation of pulse cleaning of pulse cleaning injection pipe of entrained type with velocity difference and by adding a simulation of cleaning process, this process is much closer to the actual cleaning process. Because the velocity around the mouth of the jet is relative small to the central jet, when the pulse begins, the pulse valve is open and the compressed air shoot towards the bag. The flush of the airflow to the wall of the inlet of the bag is relative small, which can increase the life of the filter bag. In the premise of the same mass flow of compressed air conditions, through the comparison of the simulation results of the pulse cleaning injection pipe of entrained type with velocity difference and the traditional mouth-line pulse jet, the results show that the pulse cleaning injection pipe of entrained type with velocity difference can spew more clean air into the filter bag and improve the cleaning effect.The article also studies the cleaning effect of these two pulse cleaning injection pipe of entrained type with velocity difference by adjusting the relative length of the center jet tube and around jet tube of the pulse cleaning injection pipe of entrained type with velocity difference. It also compares the simulation results with the initial design of pulse cleaning injection pipe of entrained type with velocity difference and optimizes the further design.Finally, this simulation research shows that pulse cleaning injection pipe of entrained type with velocity difference has obvious improvement compared to the conventional pulse cleaning injection pipe in the flow uniformity of the pulse jet and the effect of pulse flushing of the mouth of the bag. It has also increased the second introduction of clean air greatly. In summary, the pulse cleaning injection pipe of entrained type with velocity difference can be applied to practical production after further simulation and experimental study.