The Multi-parameter Detection Method Of Gas-solid Two-phase Flow In Spouted Bed And Fluidized Bed

With the progress of science and technology prompting the multiphase flowdeveloping rapidly. Gas solid two-phase flow as one of most important multiphaseflow, the pneumatic conveying process is widely exists in the modern industrial andagricultural production,such as pulverized coal conveying and combustion, catalyticcracking and dust emissions, flour conveying and cement transportation etc. Fluidizedbed and spout bed as the typical device of pneumatic conveying process which is anonlinear transient system, there exists bubble agitation, particle motion and gas solidreaction, for such chemical object with significant multiscale characteristics, thebubbles,eddy current and agglomerates is diversity. The behavior and evolution rulesof these flow structures is the bottleneck so as to reveal the multiphase flowproperties and optimization design, therefore, measuring key parameters whichincludes speed, size and concentration of particles and bubble, then describes the flowproperties and structure has vital significance on pneumatic conveying utility andreactor design.In virtue of modern measurement technique development which gives us a solutionto detect parameters, improve monitoring level, analysis the movement mechanismand optimize related experiment device of gas solid two-phase flow. In this paper,aiming at existing shortage of measuring technology and flow structurecharacterization, depend on the self built spouted bed and fluidized bed device andmulti-phase flow characterization method measured the morphology, concentration,velocity, water distribution and flow of bubble, particles, agglomerates structure.Firstly, in the aspect of gas solid two-phase flow parameters, measuring thedifferential pressure signal in the transition state of fluidized bed, then selectedrecursive key parameters by phase space reconstruction, using recursive texturestructure achieved indirect detection of bubble, provides a new way for deeper research on mechanism of bubble behavior. In terms of particle parameters,displacement and gray parameters was extracted by image velocimetry andconcentration spectrum technology that achieved detection of velocity andconcentration, the status whose resolution is low, interference degree is high anddynamic response is slow is solved.Secondly, in the aspect of agglomerates parameters, in order to simulate theaggregation phenomenon in industry, the agglomerates was manufactured by TEBatomizing nozzle, using the cascade screening method to identifying differentagglomerates, the measurement of structure characteristics and organizationalcharacteristics was accomplished.Take advantage of multi-channel conductance circuit device, the continuousfluidized affect caused agglomerates break up so that the conductance signal recovery,implemented the particles and agglomerates moisture distribution measurement. Theelectromagnetic induction coil was located in different measuring points of the spoutbed riser. Ferromagnetic powders as tracer materials of alumina particles were added.Then agglomerates flow was measured by electromagnetic induction sound signalacquisition device.Finally,on the basis of agglomerates theory analysis and experiment research, fastforecast spouted bed particle agglomeration phenomenon was put forward which hadhigher superficial gas velocity recognition rate and less response time.