The present invention relates generally to an apparatus for air bypass engines. More specifically, the present invention is an alternative modification for air-bypass engines, which directly replaces the turbofan with a fan-less thrust generating device.
The call to address the increasing bird strike threat to commercial aircraft is at the most critical moment in aviation history. Bird impacts to aircraft engines jeopardize the public safety, airline profits, and well-being of flight crew and civilians aboard commercial aircraft and on the ground. The fan blades of the turbofan, responsible for ingesting large amounts of air for thrust, are the most vulnerable component during a bird strike. The slightest damage to this component from foreign body impact, sometimes unknowingly, can result in catastrophic consequences for public safety and engine performance. Current deterrence methods to reduce bird strike risks are simply not enough to conflict with the increasing bird population and congestion of passengers in airports.
With the current aircraft industry in financial turmoil, the extended downtime, repair, and in some cases the replacement of a bird struck component, is simply too much to afford. Through known numerical simulations citing the initial onset of damage to fan blades at 110 mph, not many can afford the $24 million expenses for an aircraft engine replacement. Complications arise when addressing the impact resistance of current fan module designs. The weight of the fan blades directly affect engine performance and efficiency and are the number one dilemma for aircraft designers and engineers to further protect aircraft engines from bird collisions.
An alternative conception is to modify the shape of the fan module geometry to provide an adequate measure of strength to resist the impact loading from bird and other foreign body collisions. The rising threats of foreign body impacts to civilian aircraft impose safety, financial, and environmental risks to flight transportation. A foreign body collision with commercial aircraft is a concern to public safety and creates unwanted aircraft downtime and repairs.
The most vital element to any aircraft is propulsion or thrust. The turbofan engine is the powerhouse for the majority of commercial airliners. Because the turbofan engine is the most vulnerable component and has a 32% chance to be struck and damaged, special attention and strict certification requirements are in place to prove their capability to withstand the harshest of impact loadings. With current turbofan configurations, even the most minimal impact damage to the fan blades can lead to engine destabilization which affects operation and efficiency leading to an emergency ground and downtime for repairs. Aircraft downtime as a result from aero engine damage, with 150 hours of downtime per incident, leads to increased airport and runway congestion. Furthermore, damage to aero engines is usually not covered by aircraft engine insurance. With the current aviation industry already in a financial fiasco, they simply cannot afford the price tag of a luxury car in exchange for a turbofan blade replacement.
Most commercial airliners are equipped with turbofan engines to produce thrust. Each turbofan engine from the entrance to exist contains an inlet, a fan module, fan containment structure, low and high-pressure compressors, high and low-pressure turbines, and an exhaust. The low pressure compressor, the low pressure turbine, and the low pressure shaft complete a low pressure (LP) unit. The high pressure compressor, the high pressure turbine, and the high pressure shaft complete a high pressure (HP) unit. The fan module is typically attached to the low pressure shaft and draws in as much air as possible through the inlet into the engine. The turbofan component generates the greatest amount of total engine thrust by passing air internally. Approximately 75% of the air flow from the fan module is bypassed and used for thrust. The remaining air enters through the low and high-pressure compressors and the thermodynamic principles of fuel air combustion drive the rotation of the low pressure and high pressure shafts through the low and high-pressure turbines and out the exhaust. This cycle powers the turbofan engine with the fan module being the most critical aspect of the design. The protection and inspection of the fan blades are vital when practicing flight hazard prevention. The turbofan fan module located on the rotor and stator is the first component to be struck in the event of a foreign body impact. The last line of defense from a strike to an aircraft engine is the fan containment structure. This outer protective layer is designed and tested to permit for the containment of a fractured fan blade resulting from foreign object damage (FOD). The federal aviation administration (FAA) describes this event as fan blade out (FBO), and requires the containment structure to protect the fuselage from any shrapnel or high speed particles during impact.
While protecting against primary damage, secondary damage is also a concern when fan rotor unbalance causing further harm resulting from severe vibration which can also lead to an engine shutdown. Because of the fan blade fragility and intricate geometrical design, this component is the main cause of engine performance drop or operational failure due to impact loading from a foreign object or bird. Aircraft fan blade designers continue to address the problem with bird impact loading on these components by researching more impact resistant configurations. Some coat the fan blades with polyurethane and protect them with a layer of titanium above the composite. Even with bird deterrence and newer fan blade designs, the bird strike threat continues to rise. The main weakness to the fan blade design may be contributed from the lightweight material used, and temperamental airfoil geometry. Generally, composite materials for fan blades contain a poor ability to absorb energy and are prone to fiber splitting. Fan module improvement design is restricted to the density of the blades and geometrical shape. The components that correspond with the module are dependent upon its ability to perform adequately. Because a significant loss of thrust can transpire through the slightest fan blade deformation, this fragile component is demanded to perform under the most rigorous testing while satisfying realistic performance. Unfortunately, lightweight and high strength attributes do not go hand in hand with fan module performance and protection. A fan module too heavy, the plane will not get off the ground, and too light will undermine its stiffness.
Bird proofing fan blades to further increase impact resistance would depreciate the performance of the later components and largely affect the overall engine efficiency. Reconfiguring the geometrical arrangement of the fan module appears to be the fundamental conception while conserving the modular weight. The invention is an alternative modification for air-bypass engines, which directly replaces the turbofan with a fan-less thrust generating device. The fluid moving geometry is a helix and substitutes the turbofan's purpose.
Furthermore to having a more rigid inlet on air-bypass engines to protect against foreign body impacts, the fan-less thrust generating device decreases manufacturing costs and increases design flexibility due to simple construction while requiring less maintenance during service. A more balanced rotation could be achieved to provide for improved engine stability during operation. The performance and efficiency of aircraft engines could be improved due to a higher stiffness/weight ratio on the rotor.
All illustrations of the drawings are for the purpose of describing selected versions of the present invention and are not intended to limit the scope of the present invention.
The present invention is an alternative modification for air-bypass engines, which directly replaces the turbofan with a fan-less thrust generating device. A system of the fan-less thrust generating apparatus comprises an outer casing 1, a fluid moving device 2, and a plurality of core components 3.
The outer casing 1 comprises a front end 12, a back end 13, and an intake opening 11. The outer casing 1 is positioned as the exterior body in the present invention. In reference to
The fluid moving device 2 comprises a hub 21, a helical fin 22, and a fluid inlet 23. The fluid moving device 2 is a direct replacement for turbofan modules on existing turbofan engines. The objective of the present invention is to solve the bird strike threat to aircraft engines by increasing the rigidity of the inlet and to further protect aircraft engine's function in the event of foreign body collisions, in addition to enhancements on the helical fin 21 and its configuration. The fluid moving device 2 operates similarly to the turbofan configuration by thrusting air fluid through the engine. In reference to FIG.
2, the fluid moving device 2 is positioned within the intake opening 11 and adjacently positioned with the front end 12. The helical fin 22 is radially extended around the hub 21, and the fluid inlet 23 is adjacently positioned with the helical fin 22. In reference to
The helical fin 22 comprises a starting end 221, a final end 227, a first layer 224, a middle layer 225, a second layer 226, an inside rim 222, and an inlet edge 223. The helical fin 22 comprises geometric shape of a helix and substitutes instead of the turbofan purpose. The inside rim 222 is concentrically positioned within the helical fin 22. The middle layer 225 is positioned in between the first layer 224 and the second layer 226, and the first layer 224 and the second layer 226 are connected to the middle layer 225 creating a single layer. Because of the intense impulsive loads from bird collisions, the helical fin 22 requires careful attention to material construction and geometry. In reference to
The first layer 224, the middle layer 225, and the second layer 226 are radially positioned from the inside rim 222. In reference to
In reference to
The low pressure shaft 333 is concentrically traversed through the low pressure compressor 331 and the low pressure turbine 332. The high spool 32 is positioned in between the low pressure compressor 331 and the low pressure turbine 332, and the high pressure spool positions around the low pressure shaft 333. The connector cavity 212 in the fluid moving device 2 connects with the low pressure shaft 333 where the fluid moving device 2 is positioned in front of the low pressure compressor 331. An optional shock absorber can also be configured on the low pressure shaft 333 or within the connector cavity 212 to absorb the impulsive load, similar to a shock absorber located on an automobile strut.
The fluid moving device 2 distributes air fluid into the intake opening 11 through the fluid inlet 23. The inlet edge 223 and the conical section 214 allow air fluid to efficiently enter into the intake opening 11. Entered air fluid is then divided into an interior core flow and an exterior core flow by the compartment holder 31 according to the bypass ratio. According to the bypass ratio, majority of entered air fluid is considered as the exterior core flow. The exterior core flow flows around the plurality of core compartment creating most of the thrust in the present invention. The interior core flow flows through the low pressure compressor 331 and the high pressure compressor 321. The low pressure compressor 331 and the high pressure compressor 321 significantly increase the temperature and the pressure of the interior core flow as they compressed the interior core flow within the compartment holder 31. Since the interior core flow flows with increase velocity, the interior core flow needs to slow down before entering into the combustor 35 while keeping the existing temperature and pressure. When the interior core flow penetrates through the diffuser 34, the diffuser 34 decreases the velocity of the interior core flow and keeps the existing temperature and the pressure. Then the interior core flow enters into the combustor 35 and ignites with the jet fuel. After the interior core flow is ignited, the pressurized the interior core flow respectively flows pass the high pressure turbine 322 and the low pressure turbine 332 and exits through the exit nozzle 36. The high pressure turbine 322 is positioned within the compartment holder 31 only to extract energy from the interior core flow so that the high pressure compressor 321 can be rotated. The low pressure turbine 332 is positioned within the compartment holder 31 to extract energy from the interior core flow so that the low pressure compressor 331 and the fluid moving device 2 can be rotated.
The fluid moving device 2 can be configured to rotate in the clockwise direction and the counter-clockwise direction. In reference to
Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.
The current application claims a priority to the U.S. Provisional Patent application Ser. No. 61/526,456 filed on Aug. 23, 2011.
Number | Date | Country | |
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61526456 | Aug 2011 | US |