Numerical Simulation And Noise Calculation Of Two-phase Flow In Ultra-High Speed Flow Field Of High-speed Blender

High-speed blender can cut food in a high speed and break the plant cell wall.In the same time,it can fully release the nutrients of food and improve the taste of the product.It also has a broad market prospect.However,the speed of high-speed blender reaches an average of 14000 rpm.Thus,the ultra-high speed causes the machine to have series problems such as unstable torque and high noise.The flow field inside the high-speed blender is very complicated.It is impossible to gain a deep understanding of the essential cause of the problem by using experimental methods.Therefore,the use of numerical methods to study the flow field inside the high-speed blender is of great concern.This thesis takes a model of the high-speed blender provided by Midea Group as the research object which study the numerical simulation method of two-phase flow field.The specific research contents are as follows:(1)Study on numerical simulation method of two-phase flow field of the highspeed blender.This thesis analyzes the convergence of the high-speed blender flow field by numerically calculating the following three turbulence models: Standard k-? model,RNG k-? model and Realizable k-? model.It studies the grid processing method of near-wall region with insufficiently developed turbulence in the two-phase flow field.Also,it analyzes the setting method of dynamic grid in the rotating two-phase flow field.In addition,this thesis studies how to divide the two-phase flow field grid quickly and efficiently.It compares the performance of different solving algorithms and parameter settings when solving the two-phase flow field.What's more,it analyzes the three commonly usage of two-phase flow models and their applicable scopes.(2)Calculation and analysis of the tool holder of high-speed blender.This thesis simplifies the geometric model of the high-speed blender and establishes the flow field calculation domain.It uses Fluent Meshing to divide the grid of the high-speed blender calculation domain.It also uses numerically calculate to analyze the transient torque fluctuation curve of the tool holder of high-speed blender.This thesis performs the convergence analysis and accuracy analysis on the numerical calculation results of the high-speed blender tool holder as well as the error analysis of the numerical calculation results of the high-speed blender tool holder torque.At the end of this part,the numerical calculation results of the two-phase flow field of the high-speed blender are studied and analyzed.(3)Research on the law of the high-speed blender noise propagation in two-phase flow field and numerical calculation of the high-speed blender noise.This thesis analyzes the noise source of the high-speed blender and determine the main types of noise.It analyzes the acoustic propagation equation of the single-phase flow field and derive the propagation formula of the high-speed blender noise in the multi-phase flow field.What's more,the near-field and far-field noises of the high-speed blender are calculated numerically and the numerical calculation results are combined with the experimental results to analyze the reference significance of the numerical calculation.