Numerical model of melting, liquid migration and deformation during an ice cream meltdown test.

A numerical model was developed which describes the combined phenomena occurring during an ice cream meltdown test which is a test used by ice cream producers to estimate the quality of ice cream. It is based on the measurement of the drip loss and the deformation during melting of an ice cream block placed onto a grid at ambient temperature. This information is related to the ice cream structure and reflects the quality of the product: even partially melted, the ice cream structure should retain the liquid phase and show low deformation. The proposed model takes into account melting, liquid migration inside the ice cream structure (which is considered as an unsaturated porous medium) and deformation. The objective in developing the model is to better understand the mechanisms of the ice cream structure evolution when it is submitted to ambient conditions.
To describe the multiphysics phenomena first, energy equation is solved to describe temperature evolution of the sample. Ice crystal melting was computed by using the enthalpic approach. After partial melting, water movement inside ice cream structure is predicted by Richard’s equation. The hydraulic conductivity, the water retention characteristic and the differential moisture capacity are the parameters that control water movement inside the ice cream. Deformation of the partially melted ice cream was described by an elasticity model, Youngs’ modulus being function of the fraction of melted ice. The set of equations was solved using the CFD finite element method implemented in Comsol software. The numerical model was validated with experimental results of temperature, drip loss and deformation. The model allows determining the main parameters, related to product structure, controlling the drip loss.