Air sparging (AS) is an emerging remediation technique to remove petroleum contaminants from groundwater.The mathematic simulation of flow field is an important method to study the remediation process on-site during air sparging.A two-dimensional mathematical model of the non-steady state flow process was developed based on the AS momentum equation of saturation

relative permeability and capillary pressure.The equation was solved with the finite element method

and the distributions of saturation

velocity vectors and isobars were obtained.The results from simulation revealed that the distribution of air saturation varied with the operation time and the location of sparging well.The required time to form the steady fluid field was about 5 h.The radius of influence(ROI) was 9 m in this simulation condition.Multi-well sparging is recommended to increase the ROI

when remedying a wider area.