This project investigates both flow dynamics and microbial processes affecting NAPLs in fractured rock in a closely coupled, integrated manner. The objective is to develop a qualitative and quantitative understanding of the behavior of two and three immiscible fluid phases, microbial transformation and/or degradation, and to provide a scientific basis for field investigations, site characterization, and remedial action for NAPL contamination in fractured rocks. To achieve this, the program combines laboratory and theoretical investigations, coupled with the evaluation of conditions at relevant field sites. This report summarizes the work accomplished since inception of the project in April 1996.

Preliminary experiment has been made for cross injecting water sprays into a convective air stream to test the air-blast atomization system which has been constructed for CWS atomization in the future. A laser diffraction particle analyzing technique (the Malvern system) nonintrusively measured the drop size SMDs for various injection parameters including the convective air flow rate, flow rate of the injected liquid (distilled water), orifice diameter, and measurement locations along the two-dimensional spray plane. Buckingham-PI analysis finds the correlation of dimensionless parameters. A correlation of drop Sauter mean diameter (SMD) normalized to the orifice diameter is obtained from all the experimental data for the case of distilled water sprays.