Simulation and experimental study on the effect of deformation on heat and mass transfer in potato chips during superheated steam drying

Superheated steam drying is a drying technology with enormous potential and numerous advantages. Volume change and substantial deformation will occur on the materials to be dried during the superheated steam drying, which would affect the heat and mass transfer of the sample. However, the influence mechanism is not clear. Therefore, the nonuniform volume change of potato slices was studied, and the deformation model (DM) and the non-DM (NDM) were constructed and verified to study the heat and mass transfer processes of the sample. The results showed that there was little difference between the measured and simulated temperatures based on DM and NDM with a maximum error of 4.22% and 5.03%, respectively, but there was obvious difference between simulated moisture contents with a maximum error of 5.76% and 12.21%, respectively. The volume in DM was in good agreement with the experimental data. Temperature distribution and moisture distribution in potato chips during superheated steam drying were nonuniform and the maximum temperature gradient and moisture gradient appeared in the early period. The moisture gradient existed in the whole drying process, and the stress caused by the moisture gradient was the main factor causing the drying deformation.Practical applicationsThis work can reveal that the volume change and substantial deformation have a significant impact on the heat and mass transfer during drying. In production practice, there are many similar phenomena. The results would be helpful to understand the heat and mass transfer mechanism, optimize quality parameters to obtain better products in potato drying industry, and expand the applied range of the superheated steam drying technology. There were different deformations in the axial and radial directions of potato chips during superheated steam drying and deformation had a significant effect on the heat and mass transfer process. The moisture content distribution of potato chips changed during the drying process.image