Investigation on Thermoacoustic Instability in a Hydrogen Combustion System Using an Analytical Approach

This paper presents a one-dimensional thermo-acoustic model for a single-nozzle gas turbine combustor with a premixer from the so-called network approach.The analytic combustor model is verified with a target combustor by numerical simulations with COMSOL Multiphysics (3D FEM solver of the Helmholtz equation), and by experiments.It is found that the resonances and mode shapes from our analytic model are reasonably close to numerical and experimental ones.Combining the analytic thermo-acoustic model with a typical flame dynamical model, the effects of mean flow on the resonance and combustion instability of the combustion system are investigated.The hydrogen ratio in the fuel changes flame dynamics and consequently it has an effect on combustion instability of the combustion system.This hydrogen ratio is also analytically studied making use of the analytic combustor model and a popular flame model.