Biomass Powder Pneumatic Conveying Gas Solid Two Phase Flow Numerical Simulation

With the development of the world economy and the increase of the number of vehicles,the world's energy consumption has also increased sharply,and the energy crisis and environmental pollution problems have become increasingly serious.Practice has proved that the use of biomass energy can effectively reduce the consumption of fossil energy,which has a positive effect on solving energy problems and environmental problems.In the process of biomass energy production,powder transportation is one of the key equipment.The powder conveying and separation system with excellent performance can not only improve the production environment,but also reduce energy consumption,thus reducing the granulation cost of biomass particles and improving economic benefits.By using the basic theory and method of computational fluid dynamics,the flow field in the pipeline and cyclone separator is analyzed comprehensively by numerical simulation,and some data results are obtained.In this paper,the physical model and the mathematical model of the transport pipeline and cyclone separator are established.The internal flow field of the pipeline and cyclone separator is simulated numerically.The gas-solid two-phase vector,flow structure,flow velocity and pressure are given.By changing the flow rate of gas in the pipe,the motion track of the flow field and powder particles in the pipeline is analyzed.It is concluded that the suspended wind speed in horizontal pipe is higher than that in vertical pipe.When the wind speed is 2m/s,the powder particles are suspended.And the particles are well distributed when the wind speed is 4m/s.By changing the height of the cyclone separator's cylinder,the length of the riser pipe,the angle of the cone,an orthogonal test table was established to obtain 9 sets of related structural parameters,and 9 sets of models were established for numerical simulation.By means of range analysis,two groups of optimized structures are obtained.And the order of influence of structure on pressure drop and separation efficiency is obtained as follows:the extension length of exhaust pipe>cone Angle>cylinder height,cylinder height>exhaust pipe depth>cone Angle.But the numerical simulation has its defect,so the pressure drop measurement experiment of cyclone separator is designed.The reliability of the numerical simulation results is verified by experiments.The influence law of exhaust pipe extension amount on pressure drop index of separator is analyzed.And the experimental results show that the pressure drop of separator is the smallest when the exhaust pipe extension amount is 215mm.In this paper,the internal flow field of biomass powder was simulated and experimentally studied.The results have accumulated certain experience in studying the flow field variation of different structural parameters.It provides some guidance for the design of transportation system and the simulation analysis of flow field.