The suitability of High pressure nozzles in terms of impact upon targeted surfaces has indicated its effectiveness for the cleaning of oil production tubing scale,which has recently attract wider industrial applications considering its efficiency,ease of operation and cost benefit[1].In the Oil and gas production,these nozzles are now used for cleaning the scale deposits along the production tubing resulted mainly from salt crystallization due to pressure and temperature drop.Detailed characterizations of flat-fan nozzle in terms of droplet sizes and mean velocities will benefit momentum computations for the axial and radial distribution along the spray width,with the view of finding the best stand-off distance between the target scale and the spray nozzle.While the droplet sizes and the velocities determine the momentum at impact,although measuring droplet sizes has been known to be difficult especially in the high density spray region [2],still laboratory characterization of nozzles provide a reliable data especially avoiding uncontrollable parameters[3].While several research consider break up insensitive to the cleaning performance,this research investigate the experimental data obtained using Phase Doppler Anemometry(PDA)which led to established variation in momentum across the spray width thus,non-uniformity of impact distribution.Validation model was then developed using Fluent which verify the eroded surfaces of material using the flat-fan atomizer to have shown variability in the extent of impact actions due to kinetic energy difference between the center and edge droplets.The study's findings could be useful in establishing the effect of droplet kinetic energies based on the spray penetration,and will also add significant understanding to the effect of the ligaments and droplets effects along the spray penetration in order to ascertain their momentum impact distribution along the targeted surface.