Design And Experimental Research Of Drum-type Tea Hot Air Re-dryer

At present,tea processing is developing in the direction of cleanliness,automation,and intelligence.In the tea-making process,the processes of shaping,drying,and fragrant are particularly important.The existing equipment for shaping,drying,and fragrant processing is still there.In the initial stage of tea processing,most of them are developed by experience or experiment.Due to the single function of traditional tea processing machinery,low levels of cleanliness,automation and intelligence,and the poor shape of processed tea,it has severely restricted the tea industry in China.Therefore,this paper has developed a drum-type hot air re-dryer machine that integrates shaping,drying,frying and fragrant.The CFD-DEM coupling method is used to simulate the redrying process and pass the prototype test.Verify and analyze the rationality of the design parameters of the dryer,as well as the practicability and reliability of the dryer's work.The main research contents are as follows:(1)Through studying and analyzing the change law of tea physical property parameters and related literature data in the process of withering,greening,rolling,drying,and redrying from fresh tea leaves to finished tea,the change range of water content of tea is73.62%-4.67%,porosity change range 0.641%-0.737%,angle of repose change range50°-60°,bulk density change range 55kg/m~3-130kg/m~3,etc.,for the design and development of tea processing equipment and Improving its performance provides a theoretical basis.(2)Aiming at the problems of current tea processing equipment,such as low productivity,uneven heating of tea and low utilization of heat energy during re-dryer,a drum-type hot air re-dryer machine was designed based on the measured physical parameters of the tea.The basic structure and working principle of the dryer,and the design and research of its key components such as the drum,transmission system,redryer frame,heating device and tilt adjustment mechanism,and determined the relevant design parameters.(3)This project regards tea particles as discrete phases and hot air as continuous phases.The CFD-DEM coupling method is used to simulate and analyze the re-drying process of tea leaves,and numerical simulation is performed for three different working conditions of the re-dryer.It is found that when the shape of the anti-skid ribs in the cylinder is triangular and the rotation speed of the drum is n=15r/min,the separation ratio,temperature change,movement law and flow field of the tea are optimal,and the re-dryer effect can be optimal.(4)Carry out tea redrying machine prototype test and re-dryer tea evaluation test,and design a set of traditional drum-type tea re-dryer machine tests to compare with the re-dryer machine designed in this project.The test results show that:Rotation speed n=15r/min,when three-stage fresh leaves are used as raw materials,the productivity,water content,tea break rate,power consumption rate and effective working temperature of the redryer are 65kg/h,3.5%,0.8%,0.6kw·h/kg,130?,the sensory tea processed by the re-dryer machine can reach the super-standard,all indicators are better than traditional machines and meet the working requirements of the re-dryer machine.