Method of cooling an accessory gearbox

Abstract

The accessory gearbox (AGB) has at least one coolant passage between the AGB and the accessory for externally cooling the accessory without coolant flow inside the accessory.

What is claimed is: 
     
         1 . A method of cooling a gas turbine accessory comprising the steps of:
 circulating a coolant liquid from an engine coolant circuit around an external side surface of the accessory, and   circulating the coolant liquid within the engine to provide at least one of cooling and lubrication to at least one other part of the engine.   
     
     
         2 . The method as defined in  claim 1 , wherein the step of circulating coolant liquid around the accessory includes the step of circulating coolant liquid between an inlet of a coolant liquid passage and an outlet of the coolant liquid passage to exchange heat between the coolant liquid and the external side surface of the accessory. 
     
     
         3 . The method as defined in  claim 2 , wherein the accessory is at least partially inserted in an accessory gearbox (AGB). 
     
     
         4 . The method as defined in  claim 3 , wherein the accessory has a circular cross section. 
     
     
         5 . The method as defined in  claim 3 , wherein the coolant liquid passage is at least partially axially delimited by a pair of spaced-apart seals provided between an internal wall surface of the AGB and the external side surface of the accessory, the external side surface being radially inward of the internal wall surface. 
     
     
         6 . The method as defined in  claim 3 , wherein an internal wall surface of the AGB and the external side surface of the accessory define the coolant liquid passage. 
     
     
         7 . The method as defined in  claim 3 , wherein the coolant liquid directly contacts the external side surface of the accessory to thereby cool the accessory. 
     
     
         8 . The method as defined in  claim 7 , wherein the accessory is substantially enveloped by the internal wall surface of the AGB. 
     
     
         9 . The method as defined in  claim 7 , wherein the accessory is sealingly received by the internal wall surface of the AGB. 
     
     
         10 . The method as defined in  claim 1 , wherein the coolant liquid comprises oil and the coolant liquid circuit includes a main oil circuit communicating with at least one main bearing cavity in the engine.