Aeroacoustic modeling of a LOX/CH4 rocket engine for high-frequency combustion instability prediction analyses

High-frequency combustion instabilities represent the main technical risk faced by design engineers when developing new chemical rocket propulsion systems. Such instabilities are driven by the coupling between the flames’ heat release rate and the combustion chamber’s acoustic field. As such, they can only be assessed during detailed design...

Numerical Study on the Occurrence and Sensitivity of a High-Frequency Instability in an Advanced Can-Annular Combustion System

Gas turbines for power generation use lean premixed flames to adhere to the strict pollutant emissions regulations. Unfortunately, this often leads to thermoacoustic instabilities. These instabilities can lead to failure of system components, flame blow-off or flashback and a reduction in efficiency. Especially the high frequency transverse...

Numerical modelling of flame flashback in premixed tube burners with turbulent flow and high hydrogen content

This study presents the numerical modeling of boundary layer flame flashback in premixed tube burners with turbulent flow and high hydrogen content. The modeling approach is based on a RANS turbulence model and a flamelet combustion model using a flame surface density approach in combination with multiple turbulent flame speed correlations to...

Adverse pressure gradient flows and their influence on boundary layer flashback

Flame flashback is a failure mode in the operation of lean premixed combustion system. Due to higher flame speeds and lower quenching distances, hydrogen-rich fuel mixtures are prone to boundary layer flashback (BLF), where mixture flow speeds are low compared to the local flow velocity. Research at TU Munich (Eichler 2011) has resulted in new...

Numerical Study on the Driving and Damping of High-Frequency Instabilities in a Jet Flame Combustor

Lean premixed flames are being used in gas turbines to reduce the emission of NOx. Unfortunately, it results often in thermoacoustic instabilities. These instabilities are high amplitude pressure oscillations which cause damage to the combustion system, reduce efficiency, flame blow-off or flashback. While the cause for instabilities due to...

Combustion instabilities in combined cycle gas turbine: Analysis and modelling of the impact of operating conditions on combustion instability

With increasing discussion and legislation around emissions, gas turbines have evolved to limit their emissions, especially NOx emissions. The way of operating the gas turbine, with lean premixed combustion...

Boundary layer flashback prediction for low emissions full hydrogen gas turbine burners using flow simulation

Flame flashback is an intrinsic problem in lean premixed combustion. Due to higher flame speeds and lower quenching distances, hydrogen-rich fuel mixtures are especially prone to boundary layer flashback (BLF). Research at TU Munich (Eichler 2011, Baumgartner 2014) has resulted in new insights into the mechanism of BLF, revealing a strong...

Analysis and prediction of the influence of high frequency combustion instabilities on heat transfer in a sub-scale LOX/H2 rocket thrust chamber

The German Aerospace Centre (DLR) has in the past years been performing test runs with their experimental sub-scale combustion chambers to measure and investigate the effects of unstable combustion. Some of these investigations are focused on the heat flux to the chamber walls, changes in which can cause a significant shift in chamber wall...