Numerical Simulation Study On Filtration Performance Of Microfluidic Impactor

When the integrity of a nuclear power plant is destroyed,radioactive substances such as fissile debris and decay products are released into the containment.Therefore,the concentration of aerosols particles in the containment will increase.The radioactive material will be in the form of aerosol to the atmosphere when the pressure flow needs to be quickly released to the outside.At present,domestic and foreign nuclear power plant for aerosol filtration device is mainly mesh structure.Aerosol particles adsorbed on the mesh structure will increase the pressure drop,thereby reducing the pressure rate,and causing threat to the safety of nuclear power plant.Adsorption of radioactive material filter media will bring the problem of secondary radioactive treatment.Microfluidic inertial impactors are currently used primarily for atmospheric particulate sampling and automotive exhaust filters without the need to replace the filter media and therefore do not cause secondary radioactive solid waste treatment problems.In addition,it overcomes the effect of particle size up to three orders of magnitude of the aerosol particle diameter.Therefore,the collected particles will not block the flow of air,and the aerosol filtration for nuclear power plants can be used to filter the radioactive material without obstructing the release of containment pressure.The inertial impactor studied in this article is based on the principle of inertia,which can realize simultaneous filtering of multiple channels.The existing inertial filters are mostly single or dual flow channels,and there is no precedent for the application of inertial impactors to aerosol filtration in nuclear power plants.Therefore,the inertial impactors studied in this article are innovative in technology and concept.This paper studies the aerosol filtration performance of inertial impactors.This article analyzes the filtering principle of the microfluidic inertial impactor model by using the ICEM software to perform mixed meshing of the model and simulating the air flow field in the inertial impactor with FLUENT software.The distribution of motion trajectories in the flow field is calculated by DPM(Discrete Phrase Model).The influencing factors of the filtering performance of the inertial impactor are analyzed based on the simulation calculation results.By comparing the simulation calculation results with the experimental results,adjusting the simulation calculation method and model,a simulation calculation method suitable for calculating the filtering performance of the microfluidic inertial impactor is founded.The research purpose of this paper is to research the filtering efficiency and pressure drop of inertial impactor,and to study the main factors affecting its filtering performance.By simulating the effects of gas volume flow,aerosol particle size,channel length,and channel turning angle on the filtering performance of microfluidic inertial impactors,a model with the best filtering performance and model optimization suggestions are proposed.The simulation calculation results of the inertial impactor studied in this paper can provide references for the verification of subsequent experimental results.