22. Interacting Sprays

In many disparate engineering systems, ranging from cooling systems for microelectronics to jet engines, multiple sprays are utilized and the way they interact with one another is the subject matter of this chapter. A general overview of published research on interacting sprays is presented. Both experimental and theoretical or numerical investigations of combusting or noncombusting systems are covered. The nature of the interactions may be either direct (with actual contact between the sprays) or indirect (with no contact between the sprays). It is found that, despite the underlying common physics which reflects the mutual interaction between the sprays and their surroundings and between themselves, with few exceptions the material in the literature tends to relate to the impact of spray interactions in specific systems rather than on the fundamentals of the interaction. The question that is addressed is: is the use of multiple sprays more effective than the use of a single spray, or is it possibly detrimental? And, if the latter is true, can the situation be ameliorated by manipulation of the physics through geometric and other factors that relate to the sprays? Surveying the sparse literature on this subject gives some inkling of the important features that are relevant at a basic level. But much remains to be done, both experimentally and theoretically, in order to fully elucidate the complexities of spray interactions.