Correlation of lean blowoff in an annular combustor

Introduction F UEL effects on limits of lean blowoff and spark ignition and gas turbine engine emissions or combustor efficiency can be examined with characteristic time models. As these models continue to be validated for engines burning alternative fuels, their potential as interim design tools is demonstrated. Combustor geometry, inlet conditions, and fuel injector properties are also model parameters. The lean blowoff model was developed by Plee and Mellor for simple geometries and was extended to can-type combustors by Plee and Leonard and Mellor. This Note extends the model further to lean blowoff limits in the GE J85 annular combustor. The spark ignition and lean blowoff data for the J85 were taken by Oiler et al. The ignition data have already been correlated by Naegeli et al. The blowoff data examined here were taken at the same inlet conditions as the ignition data. The fuels, operating conditions, and blowoff equivalence ratios are listed in Table 1. The stoichiometric adiabatic flame temperatures 7^=1 were calculated at Southwest Research Institute using an in-house constant pressure equilibrium flame temperature program.