| Prior studies have shown that surface-to-surface radiation transfer within heat re-circulating combustors significantly affect their performance, especially at low Reynolds number (Re). With this as motivation, a comparison of standard titanium and gold-plated combustors was performed. Corresponding numerical simulations were performed on FLUENT 12.1, including gas-phase conduction and convection, solid-phase conduction, chemical reaction as well as surface-to-surface radiation heat transfer. It is found both experimentally and numerically that reducing surface-to-surface radiation heat transfer by reducing wall emissivity can significantly extend extinction limits at low Re where heat loss dominates the extinction behavior. Temperature distributions inside the combustor are measured by physical thermocouples as well as numerical "virtual" thermocouples for both combustors, i.e., standard titanium and gold-plated ones. |
