Authors

Abstract

The gas–solid coupling of a porous hot-air tea de-enzyming and carding machine was studied by means of computational fluid dynamics and discrete element coupling. In the numerical model, the discrete phase of tea particles was simulated using Rocky-DEM software, while the gas phase was described by ANSYS Fluent software. A mathematical model of the movement characteristics of tea particles in air was established according to the principle of fluid mechanics, to carry out dynamic analysis of tea particles’ movement process and derive how the motion of gas and tea particles is governed. Three sets of prototype tests were carried out on the basis of the design and simulation, and the average of their results taken. This showed that the hourly output of the test prototype was 3.89 kg/h, the bar-type rate was 89.14%, the de-enzyming moderation rate was 91.67%, and the average value of the measured effective operating temperature of the pot slot was 189 °C. The performance of the prototype was also tested and analyzed. After conducting a tea sensory evaluation expert appraisal, the sensory evaluation indices of the prototype-processed tea satisfied all current market requirements, being superior to those of the conventional de-enzyming and carding machine. The quality of the finished tea also met the agronomic standards and the operational requirements of the de-enzyming and carding machine.

Abstract in Chinese

通过计算流体动力学和离散元耦合的方法对多孔热风式茶叶杀青理条机的工作过程进行了气固耦合数值研究。在数值模型中，使用Rocky-dem软件模拟茶叶颗粒的离散相，ANSYS Fluent软件描述气体相。通过研究并根据流体力学原理建立了茶叶颗粒在空气中运动特性的数学模型，以此来进行茶叶颗粒运动过程的动力学分析，分析气体和茶叶颗粒的运动规律。在设计与仿真的基础上，进行了三组样机试验，取3次试验结果的平均值，结果表明：试验样机的台时产量为3.89 kg/h，成条率为89.14%，杀青适度率为91.67%，实测锅槽有效运行温度均值为189°C；并在上述基础上对试验样机进行了性能测试与分析。经茶叶感官评审专家鉴定，加工后的茶叶感官评价指标均符合要求，各项指标均优于传统杀青理条机，制得的成品茶质量达到农艺标准，且满足杀青理条机的工作要求。