Abstract:In order to deeply explore the matching mechanism of infrared and hot air in the combined drying process, and understand the influence relationship between infrared and hot air, it was necessary to build an infrared combined hot air drying test platform that can precisely control the temperature and medium humidity, wind speed and radiation temperature. Therefore, hardware such as carbon crystal coated heating plate, ultrasonic humidifier, centrifugal fan, and four-line axial flow fan was selected to design and assemble the prototype. White radish slices and kiwi slices were selected as two representative materials with uniform and uneven germplasm to verify the uniformity effect of the machine. The device consisted of a control system, a heating chamber, a tray material rack, an airflow distribution chamber, and a humidification device. The control system took the touch screen as the host, and communicated with each slave through the serial port to realize the functions of human-computer interaction, logical operation, and data storage. The specific technical parameters were that the adjustment range of hot air speed was 0~3m/s, the adjustment range of radiation temperature and hot air temperature was normal temperature to 120℃, and the adjustment range of relative humidity was 30%~60%, and the error was all within 3%. The numerical simulation technology was used to simulate the internal flow field of the airflow distribution chamber, and it was found that the combination of the pressure-stabilizing chamber and the high-and low-speed axial fans can effectively improve the problem of high wind speed along the axis of the pipeline and low surrounding. The optimized uniformity verification test results show that the maximum speed deviation ratio can reach 5.9%, and the speed non-uniformity coefficient was 4.6%. The verification test results showed that the drying characteristic curve of materials in different areas of infrared combined hot air drying was basically close to the central temperature rise curve, and the drying uniformity coefficient met the requirement of good uniformity of drying equipment.
