Impact by sand particles entrained in gas or oil product streams from down-hole well completions often causes erosive damage to the surface of sand filtration screens, heat exchangers, pipes, pipe bends, valves, gas compressors and other equipment. It is of major interest to develop designs to minimise the erosion damage. Erosion is often found to be unevenly distributed, for example erosion in a pipe elbow. Localized deep material loss or holing can lead to functional failure even though other areas of the component surface may be still undamaged. It was found that component design/geometry could often be modified to alter the flow field and even-out the erosion distribution, thus reducing the localized high erosion rate and extending the equipment service life. The optimization process can be most effectively carried out with assistance from erosion flow modelling. The objective of this paper is to describe the latest erosion flow modelling technique used at CSIRO, Australia. The technique consists of a combined laboratory physical modelling and computational fluid dynamics (CFD) approach. The physical modelling employs a paint modelling technique to illustrate the erosion patterns and advanced metrology for quantitative erosion measurements. Both of these data sets are also used to validate and improve CFD erosion modelling. The paper will show a series of case studies of erosion prediction and an example of erosion reduction through geometrical modifications with the materials used unchanged.