Boundary layer flashback model for hydrogen flames in confined geometries including the effect of adverse pressure gradient

Conference paper (2020)

Authors

S.A. Klein Energy Technology - Mechanical, Maritime and Materials Engineering
Joeri Tober Student
Research Group
Energy Technology (Mechanical, Maritime and Materials Engineering) (TU Delft)
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Published Date

2020

Language

English

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Faculty

Mechanical, Maritime and Materials Engineering

Department

Process and Energy

Research Group

Energy Technology

Abstract

The combustion properties of hydrogen make premixed hydrogen-air flames very prone to boundary layer flashback. This paper describes the improvement and extension of a boundary layer flashback model from Hoferichter [1] for flames confined in burner ducts. The original model did not perform well at higher preheat temperatures and overpredicted the backpressure of the flame at flashback by 4-5x. By simplifying the Lewis number dependent flame speed computation and by applying a generalized version of Stratford’s flow separation criterion [2], the prediction accuracy is improved significantly. The effect of adverse pressure gradient flow on the flashback limits in 2◦ and 4◦ diffusers is also captured adequately by coupling the model to flow simulations and taking into account the increased flow separation tendency in diffuser flow. Future research will focus on further experimental validation and direct numerical simulations to gain better insight into the role of the quenching distance and turbulence statistics.