Optimization and Experiment of Hot Air Tea Roasting Machine Based on CFD-Dem Coupling

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.

Section: Experimental Designmentioning

confidence: 99%

Porous Hot Air Tea De-Enzyming and Carding Machine Under Gas–solid Coupling Conditions: Numerical Simulations and Performance Testing

BI,

JIA,

QIN

et al. 2023

Analysis and Optimization Test of Operation Process of Cleaning Device of Corn Seed Harvester

Zhao

Yang

ZHANG

2022

Aiming at the current problem of the high rate of impurity and loss in the cleaning device of corn seed harvesters in China, this paper took the cleaning device of 4YZL-6 self-propelled corn seed harvester as a sample and analyzed the movement law of the material on the sieve. Box-Behnken response surface experimental design theory was used for the orthogonal tests. Wind inlet angle, airflow velocity, and crank angular velocity were selected as influencing factors, and the impurity rate and loss rate as the evaluation index of operation quality. A regression mathematical model between each influencing factor and indicator was established, and the model was also integrated and optimized. The optimal parameter combination was obtained as follows: the wind inlet angle was 37.95o, the airflow velocity was 11.3 m/s, and the crank angular velocity was 4.1 r/s. The corresponding impurity rate was 0.87% and the loss rate was 0.34%. Verification tests were conducted on the optimization results, and the test results showed that under the optimal combination of parameters, the impurity rate was 0.89% and the loss rate was 0.35%. The relative errors of each evaluation index and its model prediction were 2.29% and 2.94%, respectively.

Numerical Simulation and Experiment on Airflow Field of Corn Seed Harvester Cleaning Device

Zhao

Du²,

Yang

et al. 2023

To better analyze the distribution law of airflow in the wind sieve type cleaning device, this study took the cleaning device of Yafeng 4YZL-6S corn seed harvester as an example and conducted numerical simulation and comparative analysis of the airflow field inside the cleaning device under the sieve plate opening scales of 12, 16 and 20 mm using CFD software. The numerical simulation showed that the distribution of airflow velocity above the sieve surface was uniform at a sieve plate opening scale of 16 mm. Airflow velocity measurements were performed on the test prototype using an anemometer to verify the accuracy of the numerical simulation results. The simulation test results were supplemented by field trials, which showed that when the speed of the cleaning fan was 1200 r/min and the sieve plate opening scale was 16 mm, the impurity rate in the field harvest of the operating machinery was 1.03% and the loss rate was 1.91%. The operating effect met the standard of mechanized corn grain harvesting. This paper can provide a reference for the design and working mechanism research of corn seed harvester cleaning devices.