| Whether or not the de-enzyming and carding process is effective and ideal will directly affect the shape and quality of tea leaves.To address the problems of uneven strip shape and low efficiency in the working process,this thesis takes the 6CSL-800 gas type tea deenzyming and carding machine as the research object,and analyses the trajectory and force of tea particles in the groove of the pot of the tea de-enzyming and carding machine in terms of the height of the convex bar in the groove,the inclination angle of the groove and the number of grooves.In addition,a numerical study of the working process of the 6CSL-800gas-fired tea de-enzyming and carding was carried out by means of computational fluid dynamics and discrete element coupling.In the numerical model,Rocky-dem software was used to simulate the discrete phase of tea particles and ANSYS Fluent software to describe the gas phase.A mathematical model of the movement characteristics of tea particles in air was studied and based on the principles of fluid dynamics,which was used to carry out a kinetic analysis of the movement process of tea particles and to analyse the movement patterns of the gas and tea particles.The above work is used to improve the efficiency of the tea de-enzyming and carding machine,which is important to achieve cost reduction and efficiency of the enterprise.The main research of this thesis is as follows:1)Research on the structure and working principle of the prototype machine.The threedimensional geometric model of the 6CSL-800 gas-fired tea de-enzyming and carding machine was drawn up using UG software.The existing tea de-enzyming and carding equipment was studied to determine the functions that can be achieved by the tea deenzyming and carding machine,and the rationality of the design of the multi-slot pot structure of the de-enzyming and carding machine was studied to determine the best design parameters of the prototype.2)Research on the force model and motion process of raw materials.By understanding the structure of the prototype and its working principle,and combining with the actual production situation,the trajectory of the tea particles in the pot groove was analysed and the force model and trajectory equations of the tea particles in the pot groove were established;by studying and establishing the mathematical model of the movement characteristics of the tea particles in the air according to the principle of fluid mechanics,the kinetic analysis of the movement process of the tea particles was carried out,and the movement law of the gas and the tea particles during the working process of the tea deenzyming and carding machine was analysed.The kinetic analysis of the movement of tea particles is carried out by using the mathematical model of the movement of tea particles in air based on the principle of fluid dynamics.3)Structural design and analysis of key components of the prototype machine.The key components of the 6CSL-800 gas-fired tea de-enzyming and carding machine,including the multi-slot pot,the crank slider mechanism,the gas device,the hot air structure of the groove and other components,were designed to determine the relevant structure and specific parameters.The structural design and analysis of the key components of the tea de-enzyming and carding machine is completed,and the optimisation of the U-slot structure of the tea deenzyming and carding machine is studied.4)Simulation analysis and performance test of the prototype machine.The simulation model of tea particles was established using Rocky-dem software,with the aim of improving the rate of forming tea leaves and reducing the rate of broken tea in the de-enzyming and carding machine,and the movement of tea particles in the pot groove was simulated by Rocky-dem software under different convex bar height,groove inclination angle and groove number,and the average velocity of tea particles and the curve of interaction force were obtained.The results show that: the hourly output of the test machine is 3.89 kg/h,the rate of bar-type tea leaves is 89.14%,and the moderate rate of de-enzyming is 91.67%,and the effective operating temperature of the pot was 189°C.The performance of the test machine was tested and analysed on the basis of the above.The tea organoleptic evaluation indexes were found to be in line with the requirements of the tea organoleptic evaluation experts,and all the indexes were better than those of the traditional de-enzyming and carding machine,and the quality of the finished tea met the agronomic standards and the working requirements of the de-enzyming and carding machine.5)Three-factor,three-level orthogonal optimization test.In order to further verify the effects of the number of grooves,grooves inclination angle and convex bar height of the model 6CSL-800 gas-fired tea de-enzyming and carding machine on the de-enzyming and carding effect of tea leaves,a three-factor,three-level test was carried out according to a quadratic regression orthogonal combination rotation test,and a response surface optimization and regression model analysis were conducted using Design-Expert 11 software.Six sets of validation tests were carried out using the 6CSL-800 tea de-enzyming and carding machine as the validation test prototype,taking the maximum value of the bartype rate index and the minimum value of the broken tea rate index.When the convex bar height is 10 mm,the inclination angle of the groove is 90° and the number of grooves is 12,the bar-type rate is 89.45% and the broken tea rate is 1.63%,which means that the optimised machine has better de-enzyming and carding efficiency and quality.In this thesis,the geometrical model of the prototype of the tea de-enzyming and carding machine drawn by UG software and the simulation model of tea particles constructed by Rocky-dem software can accurately analyse the movement of tea leaves in the pot groove,which can provide theoretical reference for the subsequent design of the tea de-enzyming and carding machine and similar tea machine equipment.Using the coupled simulation method of Rocky-dem and ANSYS Fluent,the continuous phase and discrete phase models were established respectively to verify the feasibility of determining the movement of tea leaves in the pot groove based on the gas-solid coupling simulation.It can provide a theoretical reference for the design of the subsequent tea de-enzyming and carding machine and similar tea machine equipment,and also for the numerical simulation of similar tea processing equipment. |
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