The Research On The Turbine Classifier And The System Properties As Well As The Numerical Simulation Of Classification Flow Field

Because of its large proportional surface area, high surface activation, quick chemical reaction speed, strong sinter obdurability as well as its unique electric, magnetic, optic characteristics, ultrafine powder is widely applied to many industries such as micro-electronics, newly architectural material, chemicals, medicines, foodstuff, etc. The development of modern technology demands that the powdery raw materials and products possess the specialties as thin granularity, narrow distribution, uniform quality, pure material, etc, which more strictly requires the main technique in the preparing process of ultrafine powder - ultrafine crush and accurate classification. Turbine air classifier is one of the most important types among many accurate classification facilities.Scanning the current research and development situation of turbine air classifier, especially domestic work, it is found that most of it focuses on the application and exploitation of the classification equipment, or investigates the influences of various operating parameters to classification properties in the condition that the classifier's formal and structural parameters had decided, and then confirms the optimum operating parameters for the classifier. However, the study on the classification system, the classifier's working principle and the specific properties of classification flow field is still immature, especially there is few research on the motion rules of particles and the result of which has big error to the real situation. If there is any breakthrough of these basic studies, it will be possible to make some significant reformation or innovation on the form of the existing turbine air classifier, to develop more advanced classifying equipment, to improve the classifying performance greatly and to push the ultrafine accurate classification technique to a higher level.This paper begins from the dynamic theory of gas-solid tow-phase flow, deduces a differential equation of calculating separation particle diameter, uses the numerical calculating method of Runge-kutta, programs the calculating procedures to obtain thevalue of separation particle diameter in certain condition and analyses from the theory the influence of pressure to the cut size. Then it analyses the separating process of the ultrafine particles, deduces a calculating method of separation function; meanwhile it also analyses the influences of the unsteady variable and the crushing effect in the classifying process of turbine classifier to the separation function. The important section of this thesis is the numerical simulation to the property of flow field between two classifying blades in classifier, especially the motion trajectory of particles between two classifying blades. These study methods avoid the difficult experimental analyses and the results will be directly applied to the design for turbine classifier's structure and shape. Finally, the author himself, as the core member, cultivated the FW-Φ 150 horizontal turbine classifier, set up a complete ultrafine system, had a large amount of practical work for the classifier and the design, manufacture and debugging of the system and proved part of the conclusions of the theoretic study with the developed system and the existing condition.