Patent Application
20080028763
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:
During operation, air is pressurized in the compressor and mixed with fuel in the combustor for generating hot combustion gases which flow through the high and low pressure turbines that extract energy therefrom. The high pressure turbine powers the compressor through a shaft therebetween, and the low pressure turbine powers the fan through another shaft therebetween.
The exemplary turbofan engine 10 is in the form of a high bypass ratio engine mounted within a nacelle assembly 24 in which most of the air pressurized by the fan bypasses the core engine itself for generating propulsion thrust. The fan air F is preferably discharged from the engine 10 through a fan area nozzle 28 defined radially between a core nacelle 30 and a fan nacelle 32. The core exhaust gases C are discharged from the core engine through a core exhaust nozzle 34 defined between the core nacelle 30 and a center plug 35 disposed coaxially therein around an engine longitudinal centerline axis A of the engine 10 and nacelle assembly 24.
A pylon 36 is preferably located between the core nacelle 30 and the fan nacelle 32 (also illustrated in
Referring to
The pylon-located engine heat exchanger 44 and the generator heat exchanger 46 are preferably sized for “typical” cooling loads while the peaker heat exchangers 44P, 46P are used for “corner point” conditions which allows for the smallest size and most effective operation of the engine heat exchanger 44 and generator heat exchanger 46 which enables the pylon to be reasonable in size and thereby provide the most fuel efficient operation of the engine in general. The thermal management system 38 is beneficial to the engines and aircraft which have relatively high heat rejection challenges while exploiting the relatively wide variation in heat loads and fuel heat sink capacity.
The thermal management system 38 preferably communicates “typical day” heat from the engine system and the generator system to the respective engine heat exchanger 44 and generator heat exchanger 46. The thermal management system 38 handles ground idle heat from the generator system with the peaking heat exchangers 44P, 46P. The peaking heat exchangers 44P, 46P are the third layer of the thermal management system 38 and are utilized relatively rarely except for corner point conditions—at ground idle it is typically fully deployed, but may also be partially deployed at other conditions to achieve efficiency and maintain the slenderness of heat exchanger pylon. The peaking heat exchangers 44P, 46P are preferably made to be exceedingly efficient at ground idle by making their front face of the peaking heat exchanger 44P, 46P will be exposed directly to fan total pressure—without inlet losses or exhaust duct losses. The peaking heat exchangers 44P, 46P may typically be closed from 90% to 99% of a flight depending on the packaging challenge associated with the pylon 36. That is, the peaking heat exchangers 44P, 46P deployment frequencies might be traded-off versus the size of the pylon 36 that contains the engine heat exchanger 44 and the generator heat exchanger 46.
Referring to
A baffle 56 separates the airflow from the engine heat exchanger 44 and the airflow from the generator heat exchanger 46. It should be understood that various baffles and bulkheads of various shapes may be utilized to facilitate control of the separate airflows. The engine heat exchanger airflow from the engine heat exchanger exit 48 and the generator heat exchanger airflow generator heat exchanger exit 50 is controlled by the respective engine heat exchanger variable nozzle 52 and the generator heat exchanger variable nozzle 54. Thermally independent operation of the variable nozzles 52, 54 independently control airflow from the engine heat exchanger 44 and the generator heat exchanger 46 such that fan intake air is minimized and maximum thrust is produced in response to the current generator load and engine heat rejection conditions.
The pylon 36 contains the engine heat exchanger 44 and generator heat exchanger 46 which are separated by the baffle 56. The engine heat exchanger exit 48 and the generator heat exchanger exit 50 are located on opposite sides of the baffle 56 to define the separate engine heat exchanger airflow from the engine heat exchanger inlet area 60 to the engine heat exchanger exit 48 and the generator heat exchanger airflow from the generator heat exchanger inlet area 62 to the generator heat exchanger exit 50 such that the airflows are separately controlled by the respective engine heat exchanger variable nozzle 52 and the generator heat exchanger variable nozzle 54. Preferably, the engine heat exchanger variable nozzle 52 and the generator heat exchanger variable nozzle 54 are operated in response to a thermal management system controller 63 which also preferably controls operation of the pod heat exchangers 44P, 46P. Preferably, the engine heat exchanger variable nozzle 52 and the generator heat exchanger variable nozzle 54 are operated to maintain a constant temperature or otherwise selected temperature at the engine heat exchanger exit 48 and the generator heat exchanger exit 50.
Mounting the engine heat exchanger exit 48 and the generator heat exchanger exit 50 on the pylon 36 is desirable from a system weight standpoint. Preferably, a coupling arrangement may be provided to permit disconnect of the coolant conduits lines such that the heat exchangers stay with the nacelle 36 when the engine 10 is changed out.
Referring to
Referring to
It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting.
It should be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit from the instant invention.
Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention.
The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.
