Two experimental devices were designed and built to determine four coefficients KT, KM, DM and DT (or δT=DT/DM) occurring in simultaneous heat and mass transfer equations, where, KT and DM are thermal conductivity and moisture diffusivity, respectively, DT (or δT) is temperature gradient induced moisture migration coefficient and KM is moisture gradient induced heat transfer coefficient. Three food materials, i.e., potato, bread dough and bread, were tested. From this study, it was found that the value of δT was higher for low density food materials, such as bread, than for high density materials, such as potato. The coefficient δT measures moisture migration contribution due to temperature gradient within the material. The average values of δT for potato, bread dough and bread were 0.0014, 0.0059 and 0.0127 per °C, respectively. The contribution of temperature gradient to the overall moisture migration is negligible in high density materials. However, this contribution may be important in the moisture migratlon analysls for low density materials. The molsture gradient induced heat transfer coefficient was found to be negligible for the materials tested in this study.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Physical and Theoretical Chemistry