Study On The Stress And Flow Field Characteristics Of The Separating Bowl Of The Milk Separator

The milk separator is a disc separator and is the key core equipment for dairy products processing.Its core functional part,the separating bowl,has a working speed in the range of 7500r/min to 12000r/min.It is a vertical high-speed rotor with an externally suspended external center of gravity in structure.The thin-layer separation centrifugal flow field inside the bowl and the structural stress of the rotor are the key application basic theory in the design of the milk separator.The research in this area will not only reveal the separation mechanism of milk fat,optimize the design of the separator bowl structure,and develop new products.,The strength calculation and operation safety of the separator have very important theoretical value and application value.First,establish the two-dimensional flow field calculation domain model of the milk separator and divide the structure grid.Then,perform the multiphase flow numerical simulation on the two-dimensional flow field model of the separator bowl under different speeds and disc gaps in Fluent.Analyze the velocity and pressure distribution of the flow field and the separation of light and heavy phases,and use the fat content of the cream as the characteristic parameter to verify the simulation results.Secondly,the load condition and contact relationship of the parts in the separating bowl are analyzed,the static stress analysis of the integral part structure of the separating bowl is carried out,and the actual measurement of the separating bowl shell is carried out using the binocular stereo vision non-contact strain/stress test method.However,due to the structure of the separating bowl and its connection with the vertical shaft and other assembly and vibration reasons,the test reproducibility is poor,so the key to the stress simulation of the separating bowl-the setting of the contact relationship between parts is tested and verified in the form of modal analysis.,So as to verify the reliability of stress simulation.Finally,the equivalent simplification of the inner parts of the separating bowl is carried out in the form of equivalent parts,so as to simplify the analysis of the stress distribution of the bowl shell,which is commonly used to measure the strength of the separating bowl,and to compare the path of the equivalent front and rear bowl shells.The stress situation was compared and analyzed.The specific conclusions are as follows:(1).The pressure and velocity distribution of the flow field in the separating bowl conform to the basic laws of the centrifugal force field,but there is a hysteresis phenomenon in the rotational movement of the fluid relative to the movement of the disc.(2).The feed distribution in the disc channels of each layer is uneven,and the feed volume of the low-level discs is relatively large,and this trend becomes more prominent as the speed increases.(3).At the same rotation speed,the more material is fed into the thin layer channel of the disc,the longer the channel required to separate the light and heavy phases.The increase in rotation speed can shorten the channel length required for the light and heavy phase separation of materials.(4).Within the processing capacity of the separator,increasing the processing capacity of materials will not significantly reduce the separation efficiency,but if the processing capacity of the separator continues to increase,the separation efficiency will be significantly reduced.(5).The increase of the disc gap will reduce the separation efficiency of the separator,and it will increase with the increase of the disc gap value.The feed volume of the disc channel in the lower layer(especially the first two layers)is different.The uniformity phenomenon is also more prominent.(6).Through the static analysis of the integral parts of the separating bowl,the stress distribution of the inner core part shell,disc,etc.is obtained.The stress concentration of the bowl shell is most obvious in the ribs.The stress on the two ends of the disc group is the most concentrated,and the stress on the discs in the entire disc group gradually tends to be uniform from the two end discs to the middle disc.(7).The maximum stress and maximum deformation calculated by the equivalent simplified method are both smaller than those before the equivalent,but through the comparison of the stress/strain changes of each path on the equivalent front and rear shells,it is found that the equivalent front and rear shells The stress distribution is similar,and the equivalent simplified method has certain reference significance for simplifying the finite element strength check of the separating bowl.