Preserving transfer-behavior in Model Order Reduction for thermoacoustic stability analysis

Thermoacoustic systems are often modeled with a hybrid approach that combines separate models for acoustic propagation and flame dynamics. Model Order Reduction (MOR) may be applied to the acoustic subdomains to reduce the computational cost of parametric studies and robust stability analysis. In the present study, a frequency-weighted pseudo-optimal rational Krylov algorithm is used in combination with frequency-domain System Identification and cumulative reduction framework to perform MOR by preserving the transfer-behavior of the full-order subdomain. The reduced-order subdomain is then coupled with other acoustic subdomains and a flame model to yield a reduced-order thermoacoustic system. Results show that the thermoacoustic modes of the full-order system can be reproduced by the reduced-order model with good accuracy.