Sound sources in turbulent hydrogen/methane premixed jet flames

Abstract

Sound generation by hydrogen/methane premixed flames is examined using a Direct Numerical Simulation (DNS) dataset of three jet premixed flames at a Reynolds number of 10,300, with 10%, 50%, and 80% hydrogen by volume. Dowling's reformulation of Lighthill's acoustic analogy is also used to evaluate the contributions of different sound sources. Hydrogen addition increases high-frequency sound, particularly at Strouhal numbers greater than two where flame annihilation events are strong noise sources. Our analysis of Dowling's source terms reveals that the dominant contributors to the generated sound are the Lighthill's stress tensor, the time derivative of the heat release rate, the momentum c..