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【4/24 11:00~12:00 Keynote Speech】Premixed Hydrogen Flames – Instability Formation and Self-Acceleration

latest update:2022/04/20

Slovenian National Building and Civil Engineering Institute, ZAG
Dimičeva ulica 12 | 1000 Ljubljana, Slovenia

frissbe@zag.si| www.frissbe.eu

2022 Taiwan Combustion and Energy Conference,Tainan County, Taiwan, 24 April. 2022

 

Premixed Hydrogen Flames – Instability Formation and Self-Acceleration

 

GRUNDE JOMAAS

Professor and ERA Chair

Head of Department of Research for Fire-Safe Sustainable Built 

 

ABSTRACT

 

    High-fidelity experiments were conducted with hydrogen and hydrogen-propane mixture, both in air, to determine flame stability and flame propagation velocities, both normal and accelerated, for outwardly propagating spherical flames in a dual-chamber design that allowed near-constant experimental pressures of up to 60 atmospheres. The flame-front movement was monitored using Schlieren cinematography and recorded with a high-speed digital camera. Cellular instabilities, spiral waves and target patterns over the propagating flame surfaces of hydrogen flames were observed, and could be explained by existing instability theory (hydrodynamic and thermal-diffusive). Further, the cells that continuously developed over the flame surface of the expanding spherical flames increased their area and thereby the global propagation rate, resulting in the possibility of self-acceleration. The results demonstrate the strong possibility of self-similar flame acceleration, weak influence of the system pressure and diffusional-thermal instability, and a corresponding moderate spread in the power-law acceleration exponent.

 

 

 

This project has received funding from the European

 

Union's Horizon 2020 research and innovation

programme under Grant Agreement No. 952395