Numerical Simulations of a Micro Combustion Chamber (original) (raw)

The goal of this paper is to investigate the performance of microcombustors for microturbines and for propulsion. Such field is currently under rapid development because of new market requirements. In particular, main areas of interest for microcombustion are propulsion, e.g., for UAVs, and micro-electrical power generators. This study is focused on a cylindrical microcombustor fed by methane and air, with diameter and height 0.006m and 0.009m, respectively. Following a preliminary scaling analysis, two combustion models were tested, and 3D RANS numerical simulations were performed. The two combustion models simulating micro-combustor flames are the eddy dissipation model with fast chemistry and the flamelet model. Both use a novel 2-step reduced kinetics mechanism: this was properly tuned for the present device. Results indicate that the two models predict similar results for what concerns the chamber maximum temperature and outlet temperature; they differ in predicting combustion efficiency: in particular the eddy dissipation model underpredicts the measured combustion efficiency while the flamelet model overpredicts it. Compared to the eddy dissipation model, the advantage of the flamelet model is its enormous computational time saving. This work should be seen as an advance in the understanding of how to design, and what to expect from future microcombustors applications.