食品材料在干燥过程中被分为湿相和非湿相,大量实验证明水分分布具有分形特性.建立了湿相分布的分形模型,用记盒法计算出此模型中的局部含水率和分形维数.构造了用局部含水率和分形维数表示食品材料收缩率的本构关系,真实地反映了水分的内部分布形态,并计算出正确的体积收缩率.结果表明,用局部含水率表示线性与非线性体积的变化都是成立的,局部含水率可用于计算各种类型的收缩模型.通过收缩实验数据与模拟结果的对比得到很高的相关系数,证明了数学模型的正确性.
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