WO2020136684A1

WO2020136684A1 - Adjoining rim driven thruster system for exoskeletal turbofan jet engine

Info

Publication number: WO2020136684A1
Application number: PCT/IN2019/050961
Authority: WO
Inventors: Ravi Shankar Gautam
Original assignee: Ravi Shankar Gautam
Priority date: 2018-12-27
Filing date: 2019-12-27
Publication date: 2020-07-02

Abstract

This patent discloses system for generating additional thrust from the turbine of an exoskeletal turbofan jet engine. System consists of externally located rim driven ducted propeller coupled to the inner rotary drum of the exoskeletal turbofan jet engine via gear mechanism. Since the bypass thruster is separate from turbojet engine its nozzle can be appropriately designed to maximize thrust.

Description

Title of Invention: Adjoining Rim Driven Thruster System for Exoskeletal Turbofan Jet Engine

Field of Invention

[01] The present disclosure relates generally to exoskeleton turbofan jet engine.

Background of Invention

[02] Capability to generate extra thrust by usage of minimal additional fuel is the key to fuel economy for an aircraft engine. Transition from turbojet engine to turbofan engine proved to be significant technological advancement in this direction.

[03] NASA in its endeavor to achieve better efficiency for turbofan jet engine has invented exoskeletal design of turbofan jet engine in US patent US6393831B1.

Technical Problem

[04] One of the drawbacks of exoskeletal design of turbofan jet engine is that it doesn’t make use of full potential of rotary drum and stability of rotary drum is an issue.

[05] In US patent US7614210B2 turbofan jet engine with double bypass have been described. It has a disadvantage that it will increase the load on the pylon and also increase the diameter of the engine and maintenance will be complicated and challenging.

Summary of Invention

[06] One of the objectives is to provide system to generate extra thrust using turbine of jet engine in addition to provide better support to the rotor of the engine.

[07] Externally located ducted fan may be cost effectively used for thrust vectoring.

[08] Adjoining bypass thruster system, according to this invention, may help absorb more power from the propulsion plant of the engine and provide more thrust in low rpm.

[09] Adjoining bypass thruster system may facilitate to provide more support and stability to the engine more efficiently.

[10] Adjoining bypass thruster system is comparatively easy to maintain as most of its

assembly is located externally out of the engine.

Brief Description of Drawings [11] [Fig. 1] Additional Bybass thruster system assembled around exoskeletal turbofan jet engine

[12] [Fig. 2] Adjoining bypass propeller and bypass idler mechanism with exoskeletal turbofan jet engine according to this invention

[13] [Fig. 3] Front view of inner assembly of transverse power transmission mechanism.

[14] [Fig. 4] Side view of of inner assembly of transverse power transmission mechanism.

[15] [Fig. 5] Adjoining bypass propeller coupled with bypass idler mechanism.

[16] [Fig. 6] Bypass idler mechanism.

[17] [Fig. 7] Inner view of adjoining bypass propeller.

Description of Embodiments

[18] Referring to [FIG. 1], the preferred embodiment of adjoining bypass thruster system

(ABTS), according to this invention is shown to be assembled on two sides of bypass duct (EBD) of an exoskeletal turbofan jet engine (ETJE), (described in the US patent).

[19] In this invention exoskeletal turbofan jet engine (ETJE) have all the parts same as that of exoskeletal turbofan jet engine as described in the aforementioned US patent

US6393831B1 except addition of some features in its bypass assembly (without affecting the feasibility of other parts). Therefore propulsion plant of the jet engine is not shown in the diagram.

[20] Adjoining bypass thruster system (ABTS), as shown in [Fig. 1], according to this

invention comprises one transverse power transmission mechanism (PTM), a pair of bypass idler mechanism (BIM) and a pair of adjoining bypass propeller (ABP) assembled on two sides of bypass duct (EBD) of an exoskeletal turbofan jet engine.

[21] Transverse power transmission mechanism (PTM), as shown in [Fig. 2], Fig. 3] and Fig.

4], through which rotatory power from the engine is transmitted to the adjoining bypass propeller (ABP) via bypass idler mechanism (BIM) is located in the annular region between the bypass duct (EBD) and inner rotor drum of engine (EROT), towards the front side of propulsion plant, consists of two driving spur gears, namely, engine front spur gear (EGR1) and engine rear spur gear (EGR2); two spur gear support mechanism, namely, front spur gear support mechanism (GRS1) and rear spur gear support mechanism (GRS2) wherein

two driving spur gears, engine front spur gear (EGR1) and engine rear spur gear

(EGR2), are identical spoke style spur gears having outer radius less that the radius of engine bypass duct (EBD) and spokes (radially connecting the hub to the tooth face) in the form propeller blades, having orientation same as that of engine’s inner rotor propeller blades, are coaxially fixedly mounted at their hubs on front and rear portion, respectively, of outer surface of inner rotor drum (EROT);

each of spur gear support mechanism, front spur gear support mechanism (GRS1) and rear spur gear support mechanism (GRS2) consists of a pair of roller ball bearings, with (transversely) wide inner ring, located on the sides of spur gears, engine front spur gear (EGR1) and engine rear spur gear (EGR2), respectively, and each roller ball bearing is attached at their face to the inner surface of the bypass duct (EBD) and connected at their inner ring to the radially outward portion of corresponding spur gear;

spur gear support mechanism, (GRS1) and (GRS2), will help prevent the leakage of air from the bypass duct of the engine during transmission of rotatory power to bypass idler mechanism;

distance, referred to as torsional stress distribution distance, between the engine front spur gear and engine rear spur gear is appropriately chosen to minimize the torsional stress on the inner rotor drum (EROT);

engine bypass duct (EBD) has rectangular holes through which driving spur gears, engine front spur gear and engine rear spur gears (functioning as blade sections’ ducts) are exposed outside of the engine bypass duct (EBD) on its two transverse sides.

[22] Bypass idler mechanism (BIM), as shown in [Fig. 1], [Fig. 5] and [Fig. 6], meshingly adjoined to transverse power transmission mechanism (PTM), consists of a pair of idler spur gears, namely, idler front propeller (IDP1) and idler rear propeller (IDP2) coaxially mounted on a idler spool (ISPL) wherein

idler spur gears, namely, idler front propeller (IDP1) and idler rear propeller (IDP2) are identical spoke style spur gears with the spokes in the form propeller blades, having orientation opposite to that of propeller blades of engine, similar to driving spur gears with appropriate radius; idler spool (ISPL) is a cylindrical shaft, running parallel to the engine, with its ends being appropriately shaped structure, a conical structure for example, as shown in the figure;

idler spool (ISPL) is held in place by a pylon (PI) attached to the wings of the aircraft (or the fuselage) and ball bearing mounted on the cylindrical portion of the idler spool between the idler spur gears such that axis of idler spool is at same level as that of the axis of engine;

idler spur gears are appropriately placed so that they are meshingly engaged with driving spur gears of transverse power transmission mechanism (PTM).

[23] Adjoining bypass propeller (ABP) located on transverse side of exoskeletal turbofan

engine, as shown in [Fig. 7], consists of adjoining bypass rotor (AROT), adjoining bypass shell (ABS), a pair of driven spur gears, namely front adjoining spur gear (AGR1) and rear adjoining spur gear (AGR2), plurality of blade sections and plurality of roller ball bearings wherein

adjoining bypass rotor (AROT) and adjoining bypass shell (ABS) are coaxial drum like portion;

adjoining bypass rotor (AROT) is coaxially rotatably mounted within adjoining bypass shell (ABS) via a series of three roller ball bearings (ABl), (AB2) and (AB3) with one ball bearing at each end and one ball bearing in the mid portion of adjoining bypass rotor (AROT);

two driven spur gears, namely, front adjoining spur gear (AGR1) and rear adjoining spur gear (AGR2), are coaxially fixedly mounted on the outer surface of said adjoining bypass rotor (AROT);

outer radii of the gears are less than the inner radius of said adjoining bypass shell (ABS) such that there is small gap between the gear and inner surface of adjoining bypass shell (ABS);

adjoining bypass rotor (AROT) has plurality of circular blade section, , with blades as propeller blades with orientation same as that of engine propeller blades, extending inwardly from former’s inner surface;

said adjoining bypass shell (ABS) have a rectangular hole, on its side facing the idler spur gears, exposing the driven spur gears so that they can meshingly engage with idler spur gears; said adjoining bypass shell (ABS) is outwardly attached to the aircraft wing (or fuselage) via pylon (P2) so that its axis is at the same level as that of idler spool (ISPL).

[24] In one of the variation, instead of idler spool being rotatably mounted on the pylon and idler spur gears fixedly mounted on the idler spool, idler spool can be fixedly attached to the pylon and idler spur gears can rotatably mounted on the idler spool.

[25] In one of the variation, adjoining bypass propeller can be replaced with another

exoskeletal turbofan jet engine with transverse power transmission mechanism identical to (PTM).

[26] In one of the variation, pair of spur gears assembled in to transverse power transmission mechanism, bypass idler mechanism and adjoining bypass propeller described above can be replaced by a pair of helical gears to form a double helical gears.

Engine operation

[27] Whenever inner rotor drum rotates due to propulsion plant (not shown in the diagram), driving spur gears (EGR1) and (EGR2) rotates and causes idler spur gears to rotate (along with the spool) which in turn causes adjoining bypass rotor drum to rotate via adjoining spur gears.

[28] Electrically operated adjoining bypass propeller may also be used to start the engine.

Claims

[Claim 1] Adjoining bypass thruster system assembled on two sides of bypass duct of an

exoskeletal turbofan jet engine towards the front side of engine’s propulsion plant.

[Claim 2] Adjoining bypass thruster system, claimed in [Claim 1], comprises one transverse power transmission mechanism, a pair of bypass idler mechanism and a pair of adjoining bypass propeller, assembled on two sides of bypass duct of an exoskeletal turbofan jet engine.

[Claim 3] Transverse power transmission mechanism, claimed in [Claim 2], through which rotatory power from the engine is transmitted to the adjoining bypass propeller via bypass idler mechanism is located in the annular region between the bypass duct and inner rotor drum of engine, towards the front side of propulsion plant, consists of two driving spur gears, namely, engine front spur gear and engine rear spur gear; two spur gear support mechanism, namely, front spur gear support mechanism and rear spur gear support mechanism wherein

two driving spur gears, engine front spur gear and engine rear spur gear, are identical spoke style spur gears having outer radius less that the radius of engine bypass duct and spokes (radially connecting the hub to the tooth face) in the form propeller blades, having orientation same as that of engine’s inner rotor propeller blades, are coaxially fixedly mounted at their hubs on front and rear portion, respectively, of outer surface of inner rotor drum;

each of spur gear support mechanism, front spur gear support mechanism and rear spur gear support mechanism consists of a pair of roller ball bearings, with (transversely) wide inner ring, located on the sides of spur gears, engine front spur gear and engine rear spur gear, respectively, and each roller ball bearing is attached at their face to the inner surface of the bypass duct and connected at their inner ring to the radially outward portion of corresponding spur gear; spur gear support mechanism will help prevent the leakage of air from the bypass duct of the engine during transmission of rotatory power to bypass idler mechanism;

distance, referred to as torsional stress distribution distance, between the engine front spur gear and engine rear spur gear is appropriately chosen to minimize the torsional stress on the inner rotor drum; engine bypass duct has rectangular holes through which driving spur gears, engine front spur gear and engine rear spur gears (functioning as blade sections’ ducts) are exposed outside of the engine bypass duct on its two transverse sides.

[Claim 4] Bypass idler mechanism, claimed in [Claim 2], meshingly adjoined to transverse power transmission mechanism, claimed in [Claim 3], consists of a pair of idler spur gears, namely, idler front propeller and idler rear propeller coaxially mounted on a idler spool wherein

idler spur gears, namely, idler front propeller and idler rear propeller are identical spoke style spur gears with the spokes in the form propeller blades, having orientation opposite to that of propeller blades of engine, with appropriate radius;

idler spool is a cylindrical shaft, running parallel to the engine, with its ends being appropriately shaped structure, a conical structure for example, as shown in the figure;

idler spool is held in place by a pylon attached to the wings of the aircraft (or the fuselage) and ball bearing mounted on the cylindrical portion of the idler spool between the idler spur gears such that axis of idler spool is at same level as that of the axis of engine;

idler spur gears are appropriately placed so that they are meshingly engaged with driving spur gears of transverse power transmission mechanism.

[Claim 5] Adjoining bypass propeller, claimed in [Claim 2], located on transverse side of

exoskeletal turbofan jet engine consists of adjoining bypass rotor, adjoining bypass shell, a pair of driven spur gears, namely front adjoining spur gear and rear adjoining spur gear, plurality of blade sections and plurality of roller ball bearings wherein adjoining bypass rotor and adjoining bypass shell are coaxial drum-like portion; adjoining bypass rotor is coaxially rotatably mounted within adjoining bypass shell via a series of roller ball bearings located at front end, middle portion and rear end of adjoining bypass rotor;

two driven spur gears, namely, front adjoining spur gear and rear adjoining spur gear, are coaxially fixedly mounted on the outer surface of said adjoining bypass rotor;

outer radii of the gears are less than the inner radius of said adjoining bypass shell such that there is small gap between the gear and inner surface of adjoining bypass shell; adjoining bypass rotor has plurality of circular blade section, with blades as propeller blades with orientation same as that of engine propeller blades, extending inwardly from former’s inner surface;

said adjoining bypass shell have a rectangular hole, on its side facing the idler spur gears, exposing the driven spur gears so that they can meshingly engage with idler spur gears;

said adjoining bypass shell is outwardly attached to the aircraft wing (or fuselage) via pylons so that its axis is at the same level as that of idler spool.

[Claim 6] In one of the variation, instead of idler spool being rotatably mounted on the pylon and idler spur gears fixedly mounted on the idler spool, idler spool can be fixedly attached to the pylon and idler spur gears can rotatably mounted on the idler spool.

[Claim 7] In one of the variation, adjoining bypass propeller can be replaced with another exoskeletal turbofan jet engine with transverse power transmission mechanism identical to the one claimed in [Claim 3]

[Claim 8] In one of the variation, pair of spur gears assembled in to transverse power

transmission mechanism, bypass idler mechanism and adjoining bypass propeller claimed above can be replaced by a pair of helical gears to form a double helical gears.