Project Details
Projekt
Ignition and flame kernel formation in case of fluorinated refrigerants
Applicant
Dr.-Ing. Detlev Markus
Subject Area
Energy Process Engineering
Term
since 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 497007546
Fluorinated refrigerants with a low global warming potential (GWP) are often flammable. For a safety assessment of this substance class, various safety parameters must therefore be determined. The ignition of R32, R1234yf and R1234ze(E) in air by high-voltage capactive discharges near the minimum ignition energy (MIE) will therefore be investigated in detail. In doing so, the chemical and physical processes during an ignition process are examined by experimental measurements during and shortly after the discharge, during ignition as well as during the transition to self-sustaining flame propagation. This allows the loss processes to be quantified in order to clarify how much of the electrical energy provided actually contributes to ignition and which loss processes dominantly influence ignition. Taking into account the static nature of ignition by electric charges, the MIE of the substances will be determined with a low measurement uncertainty in order to provide reliable data for numerical work. Furthermore, it will be investigated how the transition into a self-sustaining flame propagation after the end of the electric discharge is influenced by spark-induced vortices as well as buoyancy-generated flow due to the strong curvature of the initial flame surface. These investigations will provide a fundamental understanding of the ignition of fluorinated refrigerants with low GWP. This should make it possible in future to also assess the safety of this important class of substances with reliable methods based on accurate data.
DFG Programme
Research Units
