*Article* **State-of-the-Art Review of Effervescent-Swirl Atomizers**

**Krystian Czernek 1,\*, Michał Hyrycz 2, Andzelika Krupi ´ ˙ nska 2, Magdalena Matuszak 2, Marek Ochowiak 2, Stanisław Witczak <sup>1</sup> and Sylwia Włodarczak <sup>2</sup>**


**Abstract:** This paper presents issues in the field of theory, construction, calculations, as well as the design of effervescent-swirl atomizers. The results of experimental studies of spraying liquids with different physico-chemical properties for this type of atomizers are discussed. Effervescentswirl atomization is a complex process and its mechanism is not fully understood. Therefore, the purpose of the manuscript is the complexity of the atomization process and its mechanism as well as the influence of individual parameters on its efficiency were thoroughly analyzed. The analyzed parameters include: atomizer design, outlet shape, gas and liquid flow rate, injection pressure, physicochemical properties of the atomized liquid, pressure drop, outflow coefficient, spray angle, quantitative droplet distributions, and average droplet diameter. Moreover, in the work, on the basis of the literature review, the results of the research related to, inter alia, the phenomenon of air core formation and the influence of a number of parameters on the efficiency of the atomization process are analyzed. The literature review included in the work makes it possible to better understand the atomization process carried out in effervescent-swirl atomizers, and also provides better design criteria and analysis of the efficiency of the tested devices. The article presents correlation equations covering the basic features of the atomization process, which relate a large number of parameters influencing the efficiency of this process and the character of the sprayed liquid, which may be useful in design practice.

**Keywords:** atomization; micro- and macro-parameters of the atomized liquid; mechanism of effervescent-swirl atomization; efficiency of atomization process; effervescent-swirl atomizer
