Forced Convective Drying Of A Porous Cube: Non-Intrusive Temperature And Mass Transfer Measurements

The evolution of the mass transfer rate and temperature of a porous body in a convective drying process shows two main stages: A constant-drying rate period and a falling-drying rate period. This study investigates the simultaneous time evolution of moisture content and local surface temperature of a porous cube inside a rectangular flow channel for a range of air flow temperatures and Reynolds numbers. The moisture content is measured using a precision mass balance. Local surface temperature distribution is measured using a thermal imaging camera. In the constant-drying rate period, an average Nusselt number in the range 7.1 <= Nu <= 13.3 and an average Sherwood number of 4.7 <= Sh <= 6.0 are calculated for a Reynolds number range of 180 <= Re <= 595. Infrared thermography shows that the falling drying rate period begins, the temperature distribution becomes non-uniform and approaches the temperature of the surroundings. This transition occurs first near the edges of the cube and, in particular, near the leading edge of the cube, as witnessed in previous studies.