Abstract

A nonequilibrium multiphase moisture and heat transfer model was developed to simulate the drying of a single walnut under hot air heating. The walnut was modeled as a 3-layer sphere by differentiating the shell, kernel, and an air gap between them. Drying characteristics of walnuts at 43, 55, 65, and 75 °C under 1.4 m/s air velocity were simulated using finite element method. The simulation results agreed well with experimental data, and the model showed good predictability for drying of walnuts with different initial moisture contents and dimension characteristics (R _adj ³ Wang, S. ; Tang, J. ; Johnson, J. A. ; Mitcham, E. ; Hansen, J. D. ; Cavalieri, R. P. ; Bower, J. ; Biasi, B. Process Protocols Based on Radio Frequency Energy to Control Field and Storage Pests in In-Shell Walnuts. Postharvest Biol. Technol. 2002, 26 , 265–273.[Crossref], [Web of Science ®] , [Google Scholar] > 0.996 for moisture and R _adj ³ Wang, S. ; Tang, J. ; Johnson, J. A. ; Mitcham, E. ; Hansen, J. D. ; Cavalieri, R. P. ; Bower, J. ; Biasi, B. Process Protocols Based on Radio Frequency Energy to Control Field and Storage Pests in In-Shell Walnuts. Postharvest Biol. Technol. 2002, 26 , 265–273.[Crossref], [Web of Science ®] , [Google Scholar] > 0.983 for temperature). The spatial distributions of liquid moisture, water vapor, and temperature in the walnut were determined through model simulation, which provided important information for understanding the mechanisms of heat and moisture transfer during walnut drying process. Findings from this study established theoretical basis for improving the walnut drying process and determining the suitable drying conditions.

摘要

建立了非平衡多相水分和热传递模型来模拟单个核桃在热风加热下的干燥。通过区分壳，仁和它们之间的气隙，将核桃建模为3层球体。使用有限元方法模拟了核桃在43、55、65和75°C下在1.4 m / s的风速下的干燥特性。模拟结果与实验数据吻合良好，该模型对不同初始水分含量和尺寸特征的核桃的干燥表现出良好的可预测性（R _adj ³ Wang S .； 唐，J. ; 约翰逊（JA） ； Mitcham，E .； 汉森，法学博士 ； 卡瓦列里，RP ； 鲍尔，J 。 Biasi，B. 基于射频能量的处理协议，用于控制带壳核桃中的田间和害虫。采后生物学。技术。 2002年，26，265 - 273。[Crossref]，[Web of Science®]，[  Google Scholar]水分和R _adj ³ > 0.996 Wang S .； 唐，J. ; 约翰逊（JA） ； Mitcham，E .； 汉森，法学博士 ； 卡瓦列里，RP ； 鲍尔，J 。 Biasi，B. 基于射频能量的处理协议，用于控制带壳核桃中的田间害虫和储存害虫。采后生物学。技术。 2002年，26，265 - 273。[Crossref]，[Web of Science®]， [Google Scholar]> 0.983）。通过模型模拟确定了核桃中液体水分，水蒸气和温度的空间分布，为了解核桃干燥过程中水分和水分传递的机理提供了重要信息。这项研究的发现为改善核桃干燥过程和确定合适的干燥条件奠定了理论基础。