A 3-D meshfree numerical model to analyze cellular scale shrinkage of different categories of fruits and vegetables during drying

In order to optimize food drying operations, a good understanding on the related transport phenomena in food cellular structure is necessary. With that intention, a three-dimensional (3-D) numerical model was developed to better investigate the morphological changes and related solid and fluid dynamics of single parenchyma cells of apple, carrot and grape during drying. This numerical model was developed by coupling a meshfree particle based method: Smoothed Particle Hydrodynamics (SPH) with a Discrete Element Method (DEM). Compared to conventional grid-based numerical modelling techniques such as Finite Element Methods (FEM) and Finite Difference Methods (FDM), the proposed model can better simulate deformations and cellular shrinkage within a wide range of moisture content reduction. The model consists of two main components: cell fluid and cell wall. The cell fluid model is based on SPH and represents the cell protoplasm as a homogeneous Newtonian liquid. The cell wall model is based on a DEM and approximates the cell wall to an incompressible Neo-Hookean solid material. A series of simulations were conducted to mimic the gradual shrinkage during drying as a function of moisture content.