山楂气体射流冲击干燥特性及干燥模型

研究不同干燥温度、风速、物料盒宽度和喷嘴高度对山楂气体射流冲击干燥特性及有效水分扩散系数的影响,采用7种数学模型拟合实验数据,得到了用于描述山楂气体射流冲击干燥的最适数学模型。结果表明:山楂的气体射流冲击干燥主要属于降率干燥。干燥温度对山楂的干燥曲线和干燥速率曲线均具有显著影响,而风速、物料盒宽度以及喷嘴高度对山楂的干燥曲线和干燥速率曲线的影响均不显著。山楂的气体射流冲击干燥有效水分扩散系数随着风温和风速的增加而增加,随着物料盒宽度和喷嘴高度的增加而降低,且最高有效水分扩散系数为9.271×10-8 m2/s。在实验范围内最适宜于描述山楂在气体射流冲击干燥过程中含水率变化规律的数学模型是Page和Modified Page模型。

Drying Characteristics and Model of Hawthorn in Air-Impingement Jet Dryer

Hawthorn was dried with an air-impingement jet dryer, and the effects of drying temperature, air velocity, drying
box width and distance from nozzle to material box on the drying characteristics and effective diffusion coefficient were
studied. In addition, the drying data were fitted to 7 drying mathematical models and the best drying model was screened
out. The results showed that air-impingement jet drying of hawthorn was a rate-falling drying process. The drying curve
and drying rate curve were significantly affected by air temperature but not significantly by air velocity, drying box width
or distance from nozzle to material box. The effective diffusion coefficient was increased with increasing air temperature
and air velocity, but decreased with increasing drying box width and distance from nozzle to material box. The maximum
effective moisture diffusion coefficient was 9.271 × 10-8 m2/s. The Page model and Modified Page model were the most
suitable for describing air-impingement jet drying behavior of hawthorn in the experimental conditions used in this study.