Atomization and spraying of liquids is a classical process engineering unit operation. The process of liquid atomization has applications in numerous industrial branches, such as in chemical, mechanical, aerospace and civil engineering, as well as in material science and technology and metallurgy, food processing, pharmaceuticals, agriculture and forestry, environmental protection, medicine, and others. Within atomization, the bulk fluid is transformed into a spray system. In impact-related spray processes, the spray typically impinges onto a solid surface or onto a liquid or semiliquid material deposited by the spray. In spray structure related processes, the main aim of the spray process is to produce dispersed spray droplets of a defined size, for example, for powder production or spray combustion. A common viewpoint for analysis of all atomization and spray processes is to be seen from multiphase flow analysis with integral heat and mass transfer.