Modelling of a low-pressure N-2-O-2 discharge and post-discharge reactor for plasma sterilization

• Type: Article in International Scientific Journal
• Date: 2007

Authors

Carlos Daniel Diogo Matias Pintassilgo (Author) FEUP; Kutasi, K (Author) Other; Loureiro, J (Author) Other

Journal

Title: PLASMA SOURCES SCIENCE & TECHNOLOGY

Vol. 16 No. 1

Pages: S115-S122

Publisher: IOP Publishing

Indexing

ISI Web of Knowledge - 22 Citations

Other information

Authenticus ID: P-004-C4X

DOI: 10.1088/0963-0252/16/1/s13

Abstract (EN): A model is used to study the afterglow of a flowing microwave discharge omega/(2 pi) = 2450 MHz, p = 667 Pa (5 Torr), in the mixture N-2-xO(2), with x = 0.7- 7% of O-2. This model considers a self-consistent kinetic description of the discharge and early-afterglow regions, followed by a 3D hydrodynamic analysis of the post-discharge chamber. The behaviour of NO( B) molecules and O(P-3) atoms is discussed in detail, since these two species play an important role in the sterilization process, respectively, due to the UV emission associated with the NO ss bands and due to erosion effects. The present work shows that a maximum in the UV emission intensity from NO ss occurs in the range 0.7-2% of O-2 added to the mixture, which is in agreement with the survival curves of spores presented by Philip et al (2002 IEEE Trans. Plasma Sci. 30 1429). In general, the oxygen atoms concentration is more important as the added O2 percentage increases. The interplay of N(S-4), O(P-3), NO(X), N-2( X, v) and NO(B) species in the overall kinetics both in the discharge and in the early-afterglow region is discussed. Particular attention is devoted to the density of NO(B) and O(P-3) in the sterilization vessel at different spatial planes and for various mixture compositions.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8