A new Sensor for the Analysis of Jet Momentum Spatial Distribution

Momentum flux is the physical property that deeply affects the evolution of jets and sprays. A sensor able to measure the spatial distribution of momentum in micro-jets and automotive diesel sprays has been designed and critically analysed. The idea behind the sensor is that of deriving the momentum flux profile of a jet/spray impinging against a flat surface by reconstructing the impact pressure distribution. The latter is realized from a set of line integrals of the impact pressure distribution along different directions and by applying the Filtered Back Projection algorithm. The performances of the sensor have hence been theoretically compared to those of a sensor that punctually measures the pressure distribution. The proposed sensor proved to be able to capture a higher frequency content of the momentum under investigation. Finally, the sensor has been employed to investigate the momentum flux of an under-expanded supersonic jet and the corresponding expected characteristic patterns of the impact pressure distribution have been obtained.