Parametric Investigation of Diesel Fuel-Air Capillary Pressure- Saturation Functions

To examine hydraulics of LNAPLs in soil، the retention curves of diesel fuel and water were both determined by hanging column method. The soil retention parameters were obtained based on van Genuchten، Brooks-Corey and Campbell’s models. In addition، the soil hydraulic conductivity for both fluids were predicted based on Mualem- Brooks-Corey، Burdine- Brooks-Corey، Mualem-van Genuchten and Campbell’s functions. The results indicated the magnitudes of the pore-size distribution parameters remained mostly unchanged and the bubbling pressure parameters were increased in diesel fuel-air compares to water-air system. The LNAPL was retained less than water owing to its negligible surface tension، yielding less needed tension to drain diesel fuel out from soils. In addition، the LNAPL retention curve was appropriately scaled based on the recommended scale factor. Due to high kinematic viscosity of diesel fuel and low soil retention for diesel fuel، the saturated and unsaturated soil hydraulic conductivity of diesel fuel was less than that of water.