| Soybean milk machine is mainly through the high-speed rotating blade to crush the particles such as soybean,and then after boiling and other processes to produce sweet and delicious soybean milk.Workers in the traditional soybean milk machine industry mainly employ experiments and experience to ensure various parameters of soybean milk machine,without considering the effect of internal flow field of the machine on its work productiveness.With the popularization of CFD technology,some research workers have studied the internal flow field of the soybean milk machine via CFD,and found that the internal flow field characteristics of soybean milk machine impact its productiveness directly.Nevertheless,most these studies were confined to the simulation study of single-phase media,which is at variance with the physical situation.It is extraordinary sophisticated for internal flow field of the soybean milk machine,and its flow mechanism is still hazy.Consequently,it is of hug practical and engineering meaning to discuss the flow characteristics of multiphase flow in the machine.In this study,the internal flow field of a certain type soybean milk machine from Joyoung company was simulated by CFD,and the effects of different rotation speeds,blade inclination angles and blade installation heights on the internal flow were studied.The critical rotation speed of soymilk vortex break,the best blade inclination combination and blade installation height are obtained,which provides a reference for the design of soymilk in terms of fluid mechanics.By contrasting the flow fields of different rotation rates,it can be discovered that around 1500 rpm is the critical value for the vortex rupture inside the soymilk machine.At this time,the vortex dissipation reaches the maximum,and the position where the vortex breaks first is on central axis of the cup and 0.01 m away from the axis with a height of y/h=0.242.With the rotation speed raise,the pressure difference between the upper and lower blades surfaces will also magnify rapidly,and the gas holdup below blade will also increase.By analyzing some characteristics of the flow field,the question why the increase of rotation speed can improve the crushing effect of the soybean milk machine is expounded from the point of fluid mechanics.The blade of the soybean milk machine is a key component,and it has a bearing on crushing efficiency of the soybean milk machine directly.Numerical calculations are carried out for different sets of upper and lower blade inclination angles.The results indicate that blade A has a remarkable influence on the flow field inside soybean milk machine,while blade B has no influence on the flow field nearly.With the raise of |?_A|,the crest value of radial velocity lessens and shifts to central axis of the cup,and the total pressure also reduces.When ?_A changes from-24° to-26°,the velocity streamline at the bottom of the cup changes from connected state to separated state,and pressure difference of the upper and lower surfaces of blade A enlarges.When?_A=-24°,the flow field has the strongest turbulent energy and eddy dissipation.When?B=28°,the pressure difference reaches the maximum.Overall,the optimal combination of inclination angles of the blades of the soybean milk machine is?_Aopt=-24°?26° and ?Bopt=28°.The flow field of 6 different soymilk blade installation heights has been numerically studied in this study.The results make known that the blade installation height has a tremendous influence on the distribution of gas-liquid two-phase,pressure and streamline inside the cavity.As increase of blade installation height,the pressure difference nearby blade A decreases,but the connectivity of flow field will become better.At about hs=16.3 mm,the flow field characteristics such as velocity vector and pressure distribution are most conducive to the efficient operation of the soybean milk machine. |
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