基于Logarithmic方程的干燥参数对稻谷水分扩散特性影响分析
Analysis moisture diffusion characteristics of paddy drying parameters based Logarithmic model equation
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摘要: 稻谷籽粒内部水分扩散的快慢决定了干燥速率。本文基于Logarithmic方程,建立稻谷水分传递动力学模型,并分析热风温度（40、50、60、70℃）和风速（0.3、0.4、0.5 m/s）对稻谷（湿基水分含量23.4%）有效水分扩散系数和扩散活化能的影响。结果表明:随着干燥温度和风速的上升,稻谷干燥速率提高,同时对应的有效水分扩散系数越大,分别为5.123×10-122.141×10-11m2/s;扩散活化能从32.94 k J/mol增加至36.30 k J/mol;对比常用的5种谷物干燥模型发现,Logarithmic模型对稻谷薄层干燥的拟合度较好,R2>0.997,RMSE<2.810×10-3,同时该模型模拟得出的有效水分扩散系数与实际差值均低于3.8×10-13m2/s,扩散活化能均低于2.53 k J/mol,与实际值基本吻合。Abstract: Drying rate of paddy rice was mainly determined by the internal moisture diffusion rate. Based on the Logarithmic equation of hot air drying,the moisture diffusion dynamics model was established,and the effects of heated air temperature( 40,50,60,70 ℃) and air velocity( 0.3,0.4,0.5 m / s) on effective diffusion coefficient and activation energy of moisture diffusion were studied. With the increase of drying temperature and air velocity,the drying rate and corresponding moisture effective diffusion coefficient was increased within the range of 5.123 ×10-12~ 2.141 × 10~(- 11)m2/ s. Meanwhile,the diffusion activation energy was increased from 32.94 k J / mol to36.30 k J / mol. Logarithmic model could fit the thin- layer drying of paddy rice with R2> 0.997 and RMSE < 2.810 ×10-3. The effective moisture diffusion coefficient and diffusion activation energy models were reliable with differences less than 3.8 × 10-13m2/ s and 2.53 k J / mol.
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