Experimental Study And Numerical Simulation In Performance Of Granular Bed Filter

In the field of industry production, it always makes waste gas that most is high temperature. If these waste gases that contain dust are direct emitted into environment, it will be harmful for human being and make environment pollution. So it must be disposed by dust remover. The granular bed filtration using the materials which are wearable, acid-resistant and high temperature- resistant is considered as the most promising developmental technique.The characteristic of granular bed filter are wearable, geostatic and high temperature- resistant, its filtrate granule will not be eroded and sensitive to gas and dust. But there are some problem for the filter such as low filtration velocity, high resistance in same dust-gas quantity, more area than bag filter and low filtration efficiency to imperceptibility granule.Internal and overseas, the research for granular bed filtration is in experiment phase now. Its systemic theoretical research is also incomplete. In order to resolve these problems mentioned above, firstly the author set up the testing set of fixed granular bed filter. Then the experiment has been done under normal temperature. From the result the author analyzed the change law of filtration efficiency and pressure drop when each factor which effects filtration efficiency changed solely. In the base of this, the author using orthogonal test to experiment the filtration efficiency and pressure drop. Analyzing the experiment result, a dimensionless efficiency and pressure drop model of filtration velocity, granular bed thickness, fill ratio, granular diameter of filter bed, gas thickness and bed thickness has been obtained by multianalysis and regression method. After comparing this formula with the test data and theoretical calculation, the author draws a conclusion that this formula could be used to predict the filtration efficiency in this experiment condition. At last the author made a theoretical derivation of filtration efficiency under non-stationary condition. Based on classical filtration theory, according the characteristic of non-stationary filtration the author set up the mathematical model and obtained an efficiency formula through deduction. Compared with experiment result, the improvement of the formula should be done in future.To optimizing the inner fluid-field of granular bed filter, this thesis makes use of CFD (FLUENT numerical simulation method) numerical simulation technology, through DPM model to discuss the correlativity between filtration efficiency, the pressure drop and their each structural parameter, granular bed characteristic parameter. On the basis of the simulation conforming to the experiment result, the suggestion to optimizing the inner fluid-field of granular bed is brought forward. Associated relationship model of infiltration rate and pressure drop is advanced to be a general optimization estimate target, the higher that is, the better performance the granular bed filtration has. Optimal parameter values are obtained by adopting the optimization toolbox of MATLAB 6.5.The conclusion of this thesis, especially the dimensionless multiple-factor regression equations can offer instruction to the designers to reduce the repetitious work and enhance the performance of research. The numerical simulation method discussed in this thesis can be used in the design and research of filters, which partly replaces the experiments, largely saves the manpower and material resources, and optimizes the evaluation of bag filter's performance...