Modeling framework for thermoacoustic phenomena

Based on the doctoral research of the Anovion founders, a framework for modeling and analysis of thermoacoustic phenomena in high-power density energy systems was developed. Typical systems of application are gas turbine combustion chambers, rocket engines, aero-engines, heating burners and thermoacoustic heat pump and refrigeration devices. The framework offers comprehensive modeling capabilities in time and frequency domain based on low-order network approaches as well as high-fidelity numerical simulation methods.



  • Modeling framework
  • Model eco-system
  • Best-practice guidelines
  • None

Thermoacoustic phenomena are understood as harmonic (acoustic) pressure oscillations at distinct frequencies in closed cavities, which are driven by an oscillating heat source. This oscillating heat source can be the heat release by combustion as e.g. in gas turbine combustion chambers or rocket engines, which leads to high-amplitude and self-sustained acoustic pressure oscillations. Such thermoacoustic oscillations can inhibit the stability of the combustion process – and thus impede the system performance – or even destroy the system itself. In this case, the occurrence of these thermoacoustics needs to be avoided, i.e. the system design needs to be thermoacoustically stable. In the case of thermoacoustic heat pumps, the heat source is simply a constant temperature perforated metal plate that is exposed to an acoustic wave. The interplay between wave and metal plate is adequately arranged, heat can be “pumped” against its natural gradient to provide cooling or heating. Here, the thermoacoustic effect is the key physical mechanism that governs the system performance. Thus, and conversely to the combustion systems above, controllably exploiting the thermoacoustic effect presents the key engineering design requirement. Regardless of whether the engineering task is avoiding or generating thermoacoustic phenomena, utilizing accurate physical models for numerical simulations and corresponding design derivations are essential for achieving this objective.


Anovion developed a modeling and analysis framework that provides all capabilities for a model-based support of engineering design tasks associated with thermoacoustic systems. The framework can be applied to all types of systems in which thermoacoustic phenomena are of importance. Prominent examples for such systems are (1) gas turbine combustion chambers, (2) rocket engines, (3) aero-engines, (4) heating burners and (5) thermoacoustic heat pump and refrigeration devices. Specifically, the framework’s distinct modeling and analysis capabilities are as follows:

  1. Low-order modeling approach for time-efficient analyses in time and frequency domain.
  2. Model eco-system for oscillation heat sources, i.e. thermoacoustic driving mechanisms.
  3. Model eco-system for acoustic attenuation, i,e. damping mechanisms and methods.
  4. Computational methods for acoustic modes and eigenfrequencies in complex 3D geometries with consideration of damping and driving mechanisms.

Using these capabilities, the following specific engineering analysis tasks can be carried out:

  1. Computation of mode shapes and associated eigenfrequencies of complex 3D system geometries with non-homogeneous base conditions, i.e. varying temperature distributions and mean flow fields.
  2. Assessment and energetic quantification of thermoacoustic energy transfer processes due to the interaction between acoustic waves and oscillatory heat sources.
  3. Assessment and energetic quantification of acoustic damping processes caused by flow interactions within the cavities or imposed by external damping devices.
  4. Linear stability assessments in frequency domain, i.e. the computation and identification whether the thermoacoustic oscillations in the considered system converge into a self-sustained state or attenuate.
  5. Simulation of limit cycle dynamics in time domain to (a) investigate nonlinear dynamics of the system, (b) virtually test and optimize the effects of external damper placements, and (c) create time domain data sets for validation of system identification techniques or machine learning based control/diagnostics approaches.

The developed framework is readily available for engineering development and design processes associated with thermoacoustic oscillations in respective technical systems. Also, best-practice recommendation can be given on how to effectively use the framework the ensure that engineering objectives are met in an efficient and high-quality manner.