Spray Diagnostics for the Twenty-First Century

A critical review of the progress in atomization and spray technology is presented. Although significant progress has been made with the benefit of developments in theory, diagnostics, and modeling, the ability to accurately prescribe or predict the spray and related two-phase turbulent flow behavior in detail has generally eluded our efforts. Available diagnostics are reviewed and some extrapolations are offered suggesting where evolving technologies in the areas of electronics, computers, software, and information technology (IT) might lead. Experimentation conducted over the past decades is criticized for lacking completeness and quality in the information measured and for its failure to identify, measure, and record all of the significant parameters. Deficiencies in measurement capabilities are recognized and arguments are presented regarding the need to integrate the experimentation and modeling. Proposed strategies include the simultaneous experimentation with interactive model predictions, which may be the only means available to completely describe the spray processes and attain the development needed in actually predicting the phenomena. Currently, the typical time scale for interactions between experiments and numerical modeling are of the order of years. Elapsed time needs to be reduced to seconds and, in many cases, to real time. Reaching the goal of accurate prediction, understanding, and the ability to prescribe spray characteristics will require highly automated data acquisition, integrated modeling, storage, and efficient, easy access to large volumes of information. This will require even greater reliance on computing power, information systems, and the Next Generation Internet (NGI).