Thermal convection in laboratory-scale porous media.

摘要

Convection experiments were conducted in laboratory-scale porous media with overall heights of 1 m and 0.24 m. The objective of these experiments was to observe the temperature and mass flow characteristics of convection structures within porous media heated from below. A thermochromic liquid crystal (TLC) tracer was used in combination with a charge couple device (CCD) digital camera to observe temperature and mass flow characteristics. The TLC tracer proved to be useful in qualitatively observing temperature and mass flow within the system. Color-temperature calibration for the tracer often had high uncertainties and non-unique color-temperature behavior limiting the quantitative quality of the data. Convection was typically characterized by the formation of plumes or fingers. Plumes tended to widen when flowing from a high to low permeability region in agreement with Darcy's law and conservation of mass. Steady-state conditions appeared to develop when temperature gradients and permeabilities were highest.