The importance of thermal dissociation in CO2 microwave discharges investigated by power pulsing and rotational Raman scattering

Dirk C.M. van den Bekerom, Jose M. Palomares Linares, Tiny Verreycken, Eddie M. van Veldhuizen, Sander Nijdam, G. Berden, Waldo A. Bongers, M.C.M. van de Sanden, Gerard J. van Rooij (Corresponding author)

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

56 Citaten (Scopus)
1 Downloads (Pure)

Samenvatting

The input power of a CO 2 microwave plasma is modulated at kHz rate in scans of duty cycle at constant average power to investigate gas heating dynamics and its relation to dissociation efficiency. Rotational temperature profiles obtained from rotational Raman scattering reveal peak temperatures of up to 3000 , while the edge temperature remains cold (500 ). During the plasma 'OFF'-period, the gas cools down convectively, but remains overall too hot to allow for strong overpopulation of vibrational modes (2200 in the core). Fast optical imaging monitors plasma volume variations and shows that power density scales with peak power. As dissociation scales with observed peak rotational temperature, it is concluded that thermal processes dominate. A simple 0D model is constructed which explains how higher power density favors dissociation over radial energy transport. Thermal decomposition is reviewed in relation to quenching oxygen radicals with vibrationally excited CO 2, to reflect on earlier reported record efficiencies of 90%.

Originele taal-2Engels
Artikelnummer055015
Aantal pagina's14
TijdschriftPlasma Sources Science and Technology
Volume28
Nummer van het tijdschrift5
DOI's
StatusGepubliceerd - 22 mei 2019

Vingerafdruk

Duik in de onderzoeksthema's van 'The importance of thermal dissociation in CO2 microwave discharges investigated by power pulsing and rotational Raman scattering'. Samen vormen ze een unieke vingerafdruk.

Citeer dit