Speaker
Description
Drying of porous media plays a central role in both natural engineering processes, particularly in evaporative cooling applications. Predicting non-isothermal drying rates remains challenging due to the strong coupling among multiphase flow, multicomponent transport, conjugate heat transfer, and phase change. This study applies a hybrid lattice Boltzmann method (LBM) that couples a multiphase LBM solver with a finite-difference heat transport solver to capture fully-coupled multiphysics. The hybrid model reproduces the classical two-stage drying behaviour: a first high-drying-rate stage at large liquid saturation (S1) and a second low-drying-rate stage (S2) as saturation decreases. It further shows that evaporative cooling slows the non-isothermal drying process compared with the isothermal case. Parametric analyses demonstrate that the S1 drying rate increases with higher inlet air temperature, faster airflow velocity, and lower inlet vapour mass fraction. However, excessively high air temperature should be avoided, since it accelerates drying beyond the capillary-pumping liquid supply to the porous media surface, leading to a markedly reduced drying capacity (i.e., the maximum amount of liquid evaporated during S1). Likewise, very low airflow velocity and high vapour content are undesirable, because they drive drying into regimes with limited vapor convection and diffusion, yielding pronounced reductions in drying rate. Based on extensive simulations spanning wide operating ranges, a universal scaling relation is proposed linking the S1 averaged drying rate to the operating conditions (i.e., air temperatre, airflow velocity, and vapour mass fraction). This provides a practical tool for estimating drying rates under diverse conditions and for optimising evaporative cooling in porous media.
| Country | Switzerland |
|---|---|
| Acceptance of the Terms & Conditions | Click here to agree |
