| Cyclone separator has the advantages of simple structure,high separation efficiency,easy operation and maintenance,etc.It is widely used in many industries and fields,such as chemical industry,mining,metallurgy,environmental protection,etc.It is an important device for dust removal and fine particle classification.With the development of economy and science and technology,various industries have higher and higher requirements on the performance of cyclone separators.To improve the performance of cyclone separators is of great significance to promote energy conservation and emission reduction of national economy and ecological environment protection.A large number of scholars have carried out a large number of basic researches on improving the performance of cyclone separators.The researches reported in the existing literature mainly focus on two aspects: one is to improve the related configuration and geometry of cyclone separators;the other is to put additional internal components into cyclone separators.These measures have been proved to be effective in improving the separation and classification efficiency of cyclone separators.In this paper,the self-designed variable diameter guide orifice was introduced into the micro cyclone separator,in order to improve the flow field characteristics of the classification space,inhibit the gas-solid two-phase short circuit flow,and thus improve the classification accuracy of mineral powder.In this study,a self-made Stairmand cyclone separator was used as the basic device to conduct an experimental study on the effect of the built-in variable diameter guide plate on the classification effect of the cyclone separator.First by using numerical simulation method to study the built-in variable diameter diversion orifice of the micro flow field characteristic of cyclone separator,the study found that the micro internal flow field in cyclone separator are improved obviously,grey ring,on its rising phenomenon of short circuit flow in the lower end of the trachea is reduced,the cone part "vortex core swing" phenomenon is significantly weakened,secondary flow flow intensity decreased significantly.This is very beneficial to improve the classification accuracy and efficiency of cyclone separators.Meanwhile,the conclusion of numerical simulation also provides guidance for subsequentThen,several groups of self-designed variable diameter guide orifice were placed in the micro cyclone separator,and the classification test was carried out.The best operating gas velocity was 15 m/s and the best feed concentration was 41.79 g/m3.hree kinds of heavy calcium carbonate powders with different particle size range,?,?and ? were tested by using the above operating parameters.The best grading efficiency of these kinds of materials with particle size ranging from 0 to 16 ?m was obtained.?materials were selected as the research object to compare the classification effect of micro cyclone separator with or without variable diameter guide orifice plate.The test results show that the variable diameter guide orifice plate can improve the classification efficiency and classification accuracy of ultrafine powder.The structural parameters such as axial position,radius size,diameter combination and hole size were studied one by one by single factor test.The influence of each parameter on the classification efficiency and precision of ultrafine powder was clarified by taking the content of particles below 6?m in the coarse particles as the index.According to the single factor test,the optimal value range of each structural parameter was determined,and the influence significance of each structural parameter and the interaction among them were studied by using the response surface method(Box-Behnken).The results show that the improvement of the classification efficiency of ultrafine powder in the micro cyclone separator has a great correlation with the structural parameters of the variable diameter orienting plate.The size of the radius and the combination of the variable diameter have a significant influence on the classification effect of ultrafine powder,and there is a strong interaction between the axial position and the radius size.The second-order polynomial prediction model of fractional efficiency was established,and the collaborative optimization research was carried out on the fractional process.Under the optimized conditions,the fractional efficiency was all over 91%.There are 54 figures,27 tables and 107 references in this paper... |
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