{"id":39702,"date":"2022-07-15T09:29:06","date_gmt":"2022-07-15T13:29:06","guid":{"rendered":"https:\/\/blogs.sw.siemens.com\/simcenter\/?p=39702"},"modified":"2026-03-26T06:26:23","modified_gmt":"2026-03-26T10:26:23","slug":"the-sound-of-hydrogen-combustion-cfd","status":"publish","type":"post","link":"https:\/\/blogs.sw.siemens.com\/simcenter\/the-sound-of-hydrogen-combustion-cfd\/","title":{"rendered":"The sound of hydrogen combustion CFD"},"content":{"rendered":"\n

What do (combustion) engineers and the Beach Boys have in common?<\/p>

They care about \u201cGood Vibrations\u201d.<\/p><\/blockquote>\n\n\n\n

Hydrogen Combustion – Stable or not stable, that is the breaking question<\/h2>\n\n\n\n

The challenges of ensuring thermoacoustic stability are still on top of the (priority) charts for combustion system designers. Now, adding hydrogen to conventional fuels is a major trend in order to meet emission and CO2 requirements. But the addition of hydrogen to conventional fuels strongly impacts the thermoacoustic response of combustion systems. And hence, things have become even more complex. Something that was stable before may now be unstable! A major headache. A headache that only hydrogen combustion CFD with thermoacoustics can resolve.<\/p>\n\n\n\n

The singing flame<\/h2>\n\n\n\n

For the Beach Boys, good vibrations were related to unmeasurable, esoteric, cosmic vibrations<\/a>. For engineers good, i.e., stable, or dampening vibrations are very real. But more importantly, the identification of bad, i.e., unstable vibrations are critical in the design of many combustion systems. To keep it with the Doors, only then will we safely ask, “Come on baby light my fire”.<\/p>\n\n\n\n

To explain the relationship between acoustics, combustion, and good design we need to go back further in time. From the swinging \u201860s to 1777. Around this time the \u201cchart-toppers\u201d would be more Mozart and Bach than the Beatles or Rolling Stones. It was also around this time that a guy named Dr. Higgins made his own music. By burning hydrogen in an open-ended tube Higgins created a \u201csinging flame\u201d. What Higgins had demonstrated was an early example of thermoacoustics. He observed the interaction between heat release (typically the flame of a combustion process), flow perturbations and acoustic oscillations.<\/p>\n\n\n

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So why is this of concern to our combustion engineers? <\/p>\n\n\n\n

Well, after lighting that fire, it comes back to the good and bad vibrations. If the acoustics of the combustion system and the unsteady heat-release are in-phase, these instabilities can continue to grow. Ultimately they may generate large-amplitude oscillations. The results range from melted components to catastrophic damage. Many combustion systems such as rockets, gas turbines, aero-engines and boilers. It is the combustion engineer\u2019s challenge to understand and mitigate these vibrations. That is the only way to allow for the safe, reliable, and efficient operation of their product.<\/p>\n\n\n\n

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