Numerical Research On Effect Of Separation Efficiency For Blade Structure Of Rotating Pulverized-Coal Classifier

Rotating pulverized-coal classifier is an important part of pulverizing system and more and more to be applied to pulverizing system in recent years, which comprehensive separation efficiency, export pulverized coal fineness and air resistance of two-phase flow and other property index will directly affect safety, economy and stable operation of pulverizing system, boiler and the unit. Numerical simulation technology is an effective method to analyze, compute and predict the flow field, so applying this technology to analyze separation efficiency, export pulverized coal fineness and other performance index will can better understand the internal flow field flow and running character of classifier and improve economy and efficiency of the pulverizing system.The computational fluid dynamics (CFD) has been used in this thesis, based on the investigation of straight blade classifier, the internal flow field of rotating pulverized-coal classifier has been simulated under different structure of twisted moving blade, and the best blade structure of rotating pulverized-coal classifier was gained.First of all, the RNG k-ε turbulence model is adopted to simulate the gas phase of straight blade rotating pulverized-coal classifier, which the regularity of flow field distribution of model section was obtained. The two-phase flow of straight blade rotating pulverized-coal classifier has been simulated, which the regularity of comprehensive separation efficiency, export pulverized coal fineness and internal air resistance with the rotor speed or system ventilation changing were gained.Second, in order to improve the property of rotating pulverized-coal classifier, a new type rotating classifier with variable cross section and twisted moving blade was given. The Fluent software is adopted to simulate two-phase flow of rotating pulverized-coal classifier with van different section and twisted moving blade under different structure, which the regularity of flow field distribution of van classifier section was gained. The two-phase flow of van rotating pulverized-coal classifier has been simulated, which the best structure of van rotating classifier moving blade was found with having the highest comprehensive separation efficiency by the trend of export pulverized coal fineness, comprehensive separation efficiency and two-phase flow air resistance with twist angle of moving blade changing were analyzed under different installation angle of rotor blade.So, the internal fluid regularity of rotating pulverized-coal classifier has been studied by numerical simulation which can better understand the internal flow field running character of rotating pulverized-coal classifier and give theoretical basis for making and reforming of rotating pulverized-coal classifier.