Interdependent lubrication systems

Abstract

A heat exchange system for use in operating equipment having a plurality of subsystems in each of which one of a plurality of working fluids is utilized to provide selected operations with there being an air and working fluid heat exchanger providing controlled cooling to cool at least one of the plurality of working fluids in its corresponding subsystem. In addition, a coupling heat exchanger is also provided connected to two of the subsystems to pass there working fluids therethrough, including the subsystem with the air and working fluid heat exchanger, to allow one of the connected subsystems to aid in cooling the other.

1 . A method for cooling lubricating liquid, the method comprising:
 flowing a first lubricating liquid through a first conduit of a first lubrication system having a first heat exchanger;   flowing a second lubricating liquid through a second conduit of a second lubrication system having a second heat exchanger;   sensing temperature of both the first and second lubricating liquids;   transferring heat from the first lubricating liquid to the second lubricating liquid via a coupling heat exchanger when the temperature of the first lubricating liquid exceeds a first threshold; and   transferring heat from the second lubricating liquid to the first lubricating liquid via the coupling heat exchanger when the temperature of the second lubricating liquid exceeds a second threshold.   
     
     
         2 . The method of  claim 1 , and further comprising:
 cooling turbine engine parts via the first lubricating liquid; and   cooling an electrical generator via the second lubricating liquid.   
     
     
         3 . The method of  claim 1 , and further comprising:
 flowing air over the first heat exchanger to cool the first lubricating liquid; and   flowing air over the second heat exchanger to cool the second lubricating liquid.   
     
     
         4 . The method of  claim 3 , and further comprising:
 transferring heat from the first lubricating liquid to a fuel via a fuel and oil heat exchanger coupled to the first conduit.   
     
     
         5 . The method of  claim 4 , wherein heat is transferred from the second lubricating liquid to the first lubricating liquid via the coupling heat exchanger, from the first lubricating liquid to the air via the first heat exchanger, and from the first lubricating liquid to the fuel via the fuel and oil heat exchanger when the temperature of the second lubricating liquid exceeds the second threshold. 
     
     
         6 . The method of  claim 4 , wherein the fuel passing through the fuel and oil heat exchanger does not pass through a heat exchanger coupled to the second conduit. 
     
     
         7 . The method of  claim 3 , wherein the first heat exchanger is positioned in a turbine engine fan duct. 
     
     
         8 . The method of  claim 7 , and further comprising:
 actuating a movable flap to selectively vary fan airstream flow over the first heat exchanger as a function of temperature of the second lubricating liquid.   
     
     
         9 . The method of  claim 3 , wherein the first and second heat exchangers are positioned in first and second turbine engine fan ducts, and further comprising:
 actuating a first movable flap to selectively open or close at least a portion of one end of the first turbine engine fan duct to selectively increase or limit fan airstream flow over the first heat exchanger; and   actuating a second movable flap to selectively open or close at least a portion of one end of the second turbine engine fan duct to selectively increase or limit fan airstream flow over the second heat exchanger.   
     
     
         10 . The method of  claim 9 , and further comprising:
 at least partially opening both the first and second movable flaps in response to one of the first and second lubricating liquids exceeding the first and second thresholds.   
     
     
         11 . The method of  claim 1 , and further comprising:
 bypassing the coupling heat exchanger, via a bypass valve, by at least one of the first and second lubricating liquids when the temperature of the first and second lubricating liquids are below the first and second thresholds, respectively.   
     
     
         12 . The method of  claim 2 , and further comprising:
 pumping the first lubricating liquid via a first pump, wherein the first lubricating liquid flows from the first heat exchanger to the coupling heat exchanger to a selected one of the turbine engine parts and the first pump.   
     
     
         13 . The method of  claim 12 , and further comprising:
 transferring heat from the first lubricating liquid to a fuel via a fuel and oil heat exchanger coupled to the first conduit, wherein the first lubricating liquid flows from a selected one of the turbine engine parts and the first pump to the fuel and oil heat exchanger to the first heat exchanger.   
     
     
         14 . A method for using a coupling heat exchanger connected in thermally coupled first and second subsystems having first and second air and working fluid heat exchangers to cool first and second working fluids therein at selectively variable rates in airstreams occurring with uses of operating equipment, the method comprising:
 sensing temperature of both the first and second working fluids;   passing the first and second working fluids through the coupling heat exchanger to transfer heat from the first working fluid to the second working fluid, and increasing the cooling provided by the second air and working fluid heat exchanger in response to temperature of the first working fluid nearing a first predetermined limit; and   passing the first and second working fluids through the coupling heat exchanger to transfer heat from the second working fluid to the first working fluid, and increasing the cooling provided by the first air and working fluid heat exchanger in response to temperature of the second working fluid nearing a second predetermined limit; and   bypassing the coupling heat exchanger by at least one of the first and second working fluids when the temperature of the first and second working fluids are substantially below the first and second predetermined limits, respective.   
     
     
         15 . The method of  claim 14 , and further comprising:
 transferring heat from the first working fluid to a fuel via a fuel and oil heat exchanger coupled to the first subsystem.   
     
     
         16 . The method of  claim 15 , wherein the fuel passing through the fuel and oil heat exchanger does not pass through a heat exchanger coupled to the second subsystem. 
     
     
         17 . The method of  claim 14 , wherein the first air and working fluid heat exchanger is positioned in a turbine engine fan duct. 
     
     
         18 . The method of  claim 17 , and further comprising:
 actuating a movable flap to selectively vary fan airstream flow over the first and working fluid heat exchanger as a function of temperature of the second working fluid.   
     
     
         19 . The method of  claim 14 , and further comprising:
 cooling turbine engine parts via the first working fluid; and   cooling an electrical generator via the second working fluid.   
     
     
         20 . A method for using a coupling heat exchanger connected in both of two thereby thermally coupled subsystems in operating equipment to cool one with the other in each of which subsystems a working fluid is utilized in providing selected operations where at least one of those subsystems has an air and working fluid heat exchanger to cool the working fluid therein at selectively variable rates in airstreams occurring with uses of the operating equipment, the method comprising:
 sensing that the working fluid in one of the coupled subsystems has a temperature nearing a predetermined limit;   passing this temperature limited working fluid through the coupling heat exchanger to transfer heat therefrom to the cooler working fluid in the other coupled subsystem; and   increasing the cooling provided by the air and working fluid heat exchanger.