TY - JOUR
T1 - Measurements and modelling of combined diffusive and advective radon transport in porous building materials
AU - Pal, van der, M.
AU - Spoel, van der, W.H.
AU - Meijer, de, R.J.
AU - Hendriks, N.A.
AU - Graaf, van der, E.R.
PY - 2005
Y1 - 2005
N2 - Measurements of combined diffusive and advective radon transport in aerated concrete have
ken made and compared with model calculations. The experimental set-up consists of a leaktight vessel conlaining a hollow aerated-concrete cylinder that divides the vessel into an inner (inside the cylinder) and outer (outside the cylinder) cornpartmenl [I]. The measurements were conducted with a radon source in the inner compartment, for a range of ventilation rates in the inner and outer compartment and for various flows through the concrete. Pressure, temperature and relative humidity in the set-up were kept constant. It was found that a combined diffusion-advective flow (Fick-Darcy) model does not describe the data. A much better fit is obtained by assuming an advective-velocity-dependent diffusivity in the model calculations. The dependence of the diffusivity on the flow velocity may result from mechanical andlor hydrodynamic dispersion. Alternatively, a model assuming two parallel porous media with distinct volume and permeability also describes the data quite well. The results of this parallel-media model indicate a preferential airflow. About 90% of the airflow is transported through 7% of the material.
AB - Measurements of combined diffusive and advective radon transport in aerated concrete have
ken made and compared with model calculations. The experimental set-up consists of a leaktight vessel conlaining a hollow aerated-concrete cylinder that divides the vessel into an inner (inside the cylinder) and outer (outside the cylinder) cornpartmenl [I]. The measurements were conducted with a radon source in the inner compartment, for a range of ventilation rates in the inner and outer compartment and for various flows through the concrete. Pressure, temperature and relative humidity in the set-up were kept constant. It was found that a combined diffusion-advective flow (Fick-Darcy) model does not describe the data. A much better fit is obtained by assuming an advective-velocity-dependent diffusivity in the model calculations. The dependence of the diffusivity on the flow velocity may result from mechanical andlor hydrodynamic dispersion. Alternatively, a model assuming two parallel porous media with distinct volume and permeability also describes the data quite well. The results of this parallel-media model indicate a preferential airflow. About 90% of the airflow is transported through 7% of the material.
U2 - 10.1016/S1569-4860(04)07042-1
DO - 10.1016/S1569-4860(04)07042-1
M3 - Article
SN - 1569-4860
VL - 7
SP - 371
EP - 380
JO - Radioactivity in the Environment
JF - Radioactivity in the Environment
ER -