Combustor igniter assembly

Abstract

A method of minimizing damage to a tip of an igniter in a combustor of a gas turbine engine includes mounting the igniter to a liner of the combustor downstream of the fuel nozzles using a floating collar, and directing pressurized air from a plenum surrounding the combustor through a plurality of purge openings and into an annular cavity surrounding the tip of the igniter. The purge openings are located in one or both of the igniter and the floating collar, and create cooling purge air jets into the annular cavity. The purge openings are formed within an arc that is disposed upstream of a bisecting plane extending along an igniter axis to a chamber axis of the combustor, such that the igniter axis lies in the bisecting plane. The igniter is free from the purge openings downstream of the bisecting plane relative to the stream of hot gases.

1 . A method of minimizing damage to a tip of an igniter in a combustor of a gas turbine engine, the ignitor having an ignitor axis along with the ignitor extends and the combustor having a chamber axis along which the combustor extends, the method comprising the steps of:
 mounting the igniter to a liner of the combustor downstream of one or more fuel nozzles using a floating collar, an annular cavity surrounding the tip of the igniter; and   directing pressurized air from a plenum surrounding the combustor through a plurality of purge openings and into the annular cavity, the purge openings located in one or both of the igniter and the floating collar and creating cooling purge air jets into the annular cavity, including providing the purge openings within an arc that is disposed upstream of a bisecting plane extending along the igniter axis to the chamber axis of the combustor such that the igniter axis lies in the bisecting plane, the igniter being free from the purge openings downstream of the bisecting plane of the igniter relative to the stream of hot gases.   
     
     
         2 . The method as defined in  claim 1 , further comprising providing the arc upstream of the bisecting plane to be 120°. 
     
     
         3 . The method as defined in  claim 1 , comprising providing the arc upstream of the bisecting plane to be 90°. 
     
     
         4 . The method of  claim 1 , wherein the cavity is defined by a circular delimiting wall, and further comprising tangentially directing the purge air jets onto the wall of the cavity.