A literature survey was carried out to examine the advances in knowledge regarding spray impingement on surfaces over the last five years. Published experiments indicate that spray impingement is controlled by various spray parameters, surface conditions, and liquid properties. One disadvantage of the published results is that the experiments have mainly been conducted with water droplets or diesel fuel, often at atmospheric conditions.
A sensitivity analysis was performed for one common impingement model. The purpose was to investigate how the model described different phenomena when different parameters were changed, including wall temperature, wall roughness and injection velocity of the spray.
The model tested showed sensitivity to surface roughness, whereas changes in wall temperature only resulted in increased evaporation from the surface. The increase of injection velocity resulted in a decrease of fuel on the wall by 70%.
Our conclusions are that more experiments with gasoline droplets and sprays must be performed in order to investigate how a liquid with these properties behaves under engine-like conditions. Parameters such as the presence of a liquid film, its thickness and multiple droplet interactions must also be taken into account. Thus the models need to be further refined.