Integrated oil tank with passive thermal modulation

Abstract

An oil tank for a gas turbine engine. The oil tank includes an oil cavity defined within structural walls of a nacelle of the gas turbine engine, the oil cavity having an oil inlet and an oil outlet. At least one of the structural walls has an interior side facing the oil cavity and an exterior side. The interior side includes a plurality of upstanding protrusions extending into the oil cavity and fully immersed in oil when the gas turbine engine is in use during steady state operation. The exterior side includes a plurality of fins extending therefrom and exposed to an ambient air stream during steady state operation of the gas turbine engine.

1 . An oil tank for a gas turbine engine, comprising;
 an oil cavity defined within structural walls of a nacelle of the gas turbine engine, the oil cavity having an oil inlet and an oil outlet;   at least one of the structural walls having an interior side facing the oil cavity and an exterior side, the interior side including a plurality of upstanding protrusions extending into the oil cavity and fully immersed in oil when the gas turbine engine is in use during steady state operation, the exterior side including a plurality of fins extending therefrom and exposed to an ambient air stream during steady state operation of the gas turbine engine.   
     
     
         2 . The oil tank as defined in  claim 1 , wherein the upstanding protrusions within the oil cavity have a height of 90 to 300 thousandths of an inch. 
     
     
         3 . The oil tank as defined in  claim 1 , wherein the upstanding protrusions includes a circular or an elliptical cross-sectional shape. 
     
     
         4 . The oil tank as defined in  claim 1 , wherein the upstanding protrusions include a porous structure. 
     
     
         5 . The oil tank as defined in  claim 1 , wherein the spacing between the upstanding protrusions varies between 60 and 200 thousandths of an inch. 
     
     
         6 . The oil tank as defined in  claim 1 , wherein the plurality of fins are aligned with the direction of travel of the ambient air stream. The oil tank as defined in  claim 1 , further comprising an inlet scoop directing the ambient air stream to the plurality of fins. 
     
     
         8 . The oil tank as defined in  claim 1 , further comprising an outlet scoop directing air from the plurality of fins back to the ambient air stream. 
     
     
         9 . A gas turbine engine comprising:
 a casing of the gas turbine engine;   an oil system including an oil tank, a plurality of oil lines interconnecting the oil tank with components of the gas turbine engine requiring one or more of heating or cooling, and at least one pump configured for circulating oil through the oil system; and   the oil tank being integrated within the casing of the gas turbine engine and having structural walls enclosing an oil cavity, the oil tank including an oil inlet and an oil outlet in communication with the oil cavity, at least one of the structural walls including an interior side facing the oil cavity and an exterior side, the interior side having a plurality of upstanding protrusions extending into the oil tank and configured to be fully immersed in oil when the gas turbine engine is in use during steady state operation, the exterior side including a plurality of fins exposed to ambient air stream during operation of the gas turbine engine.   
     
     
         10 . The gas turbine engine of  claim 9 , wherein the ambient air stream flows through a bypass air duct between a nacelle and a core casing of the gas turbine engine. 
     
     
         11 . The gas turbine engine of  claim 9 , wherein the at least one pump includes a main oil pump to which cooled oil is directed from the oil outlet. 
     
     
         12 . The gas turbine engine of  claim 9 , further comprising a fuel and oil heat exchanger upstream of the oil tank, the fuel and oil heat exchanger transferring heat from hot oil to engine fuel being directed to a fuel supply system. 
     
     
         13 . The gas turbine engine of  claim 9 , wherein each upstanding protrusion has a height of 90 to 300 thousandths of an inch. 
     
     
         14 . The gas turbine engine of  claim 9 , wherein each upstanding protrusion includes one of a circular or elliptical cross-sectional shape. 
     
     
         15 . The gas turbine engine of  claim 9 , wherein each upstanding protrusion includes one of a porous structure. 
     
     
         16 . The gas turbine engine of  claim 9 , wherein the spacing between each upstanding protrusion varies between 60 and 200 thousandths of an inch. 
     
     
         17 . The gas turbine engine of  claim 9 , wherein the plurality of fins are aligned with the direction of travel of the ambient air stream. 
     
     
         18 . A method for thermally regulating oil in a gas turbine engine, comprising;
 feeding oil to be thermally regulated into an oil tank integrated within a nacelle of the gas turbine engine; and   directing the oil through a plurality of upstanding protrusions extending into the oil tank from an interior side of a structural wall of the oil tank, the upstanding protrusions transferring heat between the oil within the oil tank and an ambient air stream flowing through a plurality of fins located on an exterior side of the structural wall.   
     
     
         19 . The method of  claim 18 , further comprising transferring heat from hot oil to engine fuel being directed to a fuel supply system. 
     
     
         20 . The method of  claim 18 , further comprising directing the ambient air stream through a bypass air duct between a nacelle and a core casing of the gas turbine engine to the plurality of fins.