| At present,in order to satisfy the continuous flow of the processing industry chain,most of the large-scale corn cooking processing equipment is used for processing.According to the principle of "hourglass timing",the inside of the continuous cooking device is composed of multiple layers of funnel superposition,but the device has some defects when cooking corn.It is difficult to control the cooking time because of the inhomogeneous flow of corn grains in the funnel type device.The water content of corn grains is higher because of insufficient cooking time or too long cooking.For this reason,it is of great significance to ensure the uniform flow and heating of the particles in the cooking device for the further development of the steam-corn tablet industry.Steam corn pressing technology can be briefly summarized as follows: after soaking the corn with high temperature steam,starch inside the corn will undergo gelatinization reaction,with the purpose of enhancing the digestibility of animals.In the process of cooking corn,the cooking time and heating state of each grain affect the subsequent process of production chain.At present,it is difficult for the cooking devices in the market to ensure the relatively uniform flow of internal particles,which leads to a large difference in the control of cooking time of corn particles.In this thesis,the flow characteristics of the internal particles in the unloading process are analyzed by simulating the traditional funnel cooking device.To solve the problem of uneven heating and flow of particles in the cooking device and the large difference in the outflow time of particles.Through grooving treatment at the wall surface of the funnel,the lower steam flows upward through the groove holes on the wall of the funnel,penetrating the corn pile from the pores of the corn pile,so that the corn particles inside the silo are heated evenly.A shunt is added into the newly designed device,and the flow state of particles in the design device is analyzed through the discharge of the device.By changing the half top Angle of the funnel and the diverter,the change of the flow state of the internal particles is studied,so that the final device not only needs to solve the common funnel flow phenomenon,but also solve the particle retention phenomenon,so that the corn particles basically reach the whole flow discharge state.In a large population of particles,the discontinuity of particles is difficult to test the velocity of each particle experimentally.As for how to get the flow state of the particles inside the silo,experiments can be carried out according to the discrete element simulation software currently used by scholars.The discrete element simulation software can capture the flow state and flow velocity of each particle and comprehensively analyze the flow velocity and flow trajectory of particles at different levels in the discharge process.It is more advantageous for the measurement of multi-scale devices and multi-target particles,without investing more manpower and financial resources.According to the actual shape and size of corn particles and the design specification of silo,the mathematical model of the cooking device that can produce 1 ton of corn per hour is constructed.The physical model of the device is established by using UG three-dimensional modeling software,and the model is imported into EDEM discrete element simulation software.The model is analyzed and selected according to the accumulation of particles,and the iterative calculation of torque and force in the process of particle unloading is conducted through Newton’s second Law.The results show that the discharge device with funnel half top Angle of55° and shitter half top Angle of 30° can solve the particle retention phenomenon in silo and make the corn particles flow evenly inside the silo. |
PDF Full Text Request