| Chinese tea industry is booming and prospering,and it is an ecological and healthy agricultural industry in the Healthy China 2030 strategy.As the first process of green tea processing,green tea processing is of great significance in the whole process of tea processing.The quality of green tea processing directly affects the quality of finished tea.Due to the single process,low efficiency and inconsistent quality of the traditional green machine,the quality of tea has been greatly affected,and the development of my country’s tea industry has been severely restricted.Therefore,this paper proposes the coupled greening process of superheated steam,high temperature hot air and hot drum,and designs a steam-heat-air coupled drum-type tea fixation machine.Based on the finite element and discrete element coupling simulation methods,the greening process is numerically simulated and analyzed The superiority of the superheated steam,high temperature hot air and hot roller coupling fixing process is discussed,and the rationality of each design parameter of the fixation machine,as well as the practicability and reliability of the fixation machine are verified and analyzed through the prototype test.The main research contents are as follows:（1）A finishing process of coupling superheated steam,high temperature hot air and hot drum is proposed.By analyzing the application status of superheated steam drying technology and hot air drying technology in tea greening process,a coupled thermal energy killing process with superheated steam,high temperature hot air and hot drum was proposed,and the heat and mass transfer mechanism of tea greening process was theoretically analyzed.（2）A steam-heat-air coupling drum type tea fixation machine is designed.By analyzing the problems existing in the current process of tea greening,a coupled thermal energy tea fixation machine is designed,the basic structure and working principle of the fixation machine are expounded,and the main components such as steam and heat cycle recovery and reheating device,drum and transmission device are determined.Design parameters related to heat transfer and material transfer devices.（3）The feasibility simulation test of the tea fixation machine was carried out.Based on the finite element and discrete element coupling simulation calculation method,the simulation analysis of the greening process of fresh tea leaves is carried out.The numerical simulation of the greening process,drum speed and guide vane parameters is carried out.It is concluded that when the drum speed is 28r/min,the superheated steam,The hot air and the hot roller are coupled with the fixing process,and the fixing effect is better when 6 spiral composite guide vanes are evenly distributed in the cylinder.（4）The performance verification test of the tea fixation machine prototype was carried out.Taking the contents of green leaves,appearance evaluation,energy cost of greening,greening time and sensory evaluation of finished tea as evaluation indicators,the effects of four greening processes on the quality of greening leaves and finished tea were explored.And according to the orthogonal test,the optimal working parameter combination of the fixation machine is determined as follows: the coupling fixing process of superheated steam,high temperature hot air and hot drum is adopted,the drum speed is 28r/min,and the predicted optimal response value is: the content of tea polyphenols is 17.48%,the amino acid content is 3.78%. |
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