Air curtains (ACs) are plane turbulent impinging jets that are used to separate two environments in terms of heat and mass transfer while still allowing traffic between these environments. The many applications of ACs across a wide variety of industries makes the evaluation of their performance an important but difficult task. The aim of this paper is to introduce a performance indicator, called the adapted separation efficiency, that is suitable for different types of systems that may involve different AC configurations (downward blowing, upward blowing, lateral blowing, multiple jets, etc.) at multiple scales, different transported quantities (heat, water vapor, particles, gases, etc.) subjected to various transport mechanisms (advection, molecular and turbulent diffusion) and varying environmental conditions (gradients in environmental pressure and/or density). It is defined using a conventional efficiency formula. The principle of this performance indicator is illustrated with a generic case study where the performance is evaluated for two basic AC configurations involving cross-jet pressure and density gradients, as well as different jet momentum fluxes. The case study is conducted based on computational fluid dynamics employing validated large eddy simulations.
Bibliographical noteFunding Information:
The Research Foundation – Flanders (FWO) is acknowledged for the financial support of the first author (project FWO G085618N ). In addition, Twan van Hooff is currently a postdoctoral fellow of the Research Foundation – Flanders (FWO) and acknowledges its financial support (project FWO 12R9718N ). This work was sponsored by NWO Exacte Wetenschappen (Physical Sciences) for the use of supercomputer facilities, with financial support from the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (Netherlands Organization for Scientific Research, NWO) . Finally, the authors gratefully acknowledge the partnership with ANSYS CFD.
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- Air curtain
- Computational fluid dynamics (CFD)
- Impinging jet
- Separation efficiency