Durability flame stabilizing fuel injector with impingement and transpiration cooled tip

Abstract

The invention is a tangential entry, premixing fuel injector (,) for the combustion chamber (,) of a turbine engine. The injector includes a pair of arcuate scrolls (,) defining the radially outer boundary of a mixing chamber (,) and a pair of air entry slots (,) for admitting a stream of primary combustion air tangentially into the mixing chamber. The scrolls also include an axially distributed array of primary fuel injection passages (,) for injecting a primary fuel into the primary air stream. A flame stabilizing fuel injector centerbody (,) includes an impingement and transpiration cooled outlet nozzle (,) for introducing secondary fuel and secondary air into the combustion chamber. The nozzle (,) includes an impingement plate(,) with an array of impingement ports (,) and a tip cap (,) with an array of discharge passages (,). The impingement ports and discharge passages are in series flow, misaligned relationship so that secondary air exiting from the impingement ports impinges on the tip cap and flows through the core discharge passages to impingement cool and transpiration cool the nozzle. The disclosed injector runs cooler than a more conventional tangential entry injector and therefore is more durable. The improved durability is achieved even though the disclosed injector uses less cooling air than a more conventional tangential entry injector and discharges the cooling air at a lower velocity. The reduced cooling air quantity helps to minimize carbon monoxide emissions and the reduced discharge velocity improves the spatial and temporal stability of the combustion flame.