BACKGROUND

The present invention relates to a thrust device. More specifically, the present invention relates to a device comprising: a serpentine conduit for channelling an airstream there along; and an aerofoil disposed within the conduit for augmenting the forward thrust of a vehicle to which the thrust device is secured.

It is known for compressors to include a serpentine / convoluted conduit with vanes / aerofoils. An example of such a compressor is described in W02021/068008 “Multi-stage rotor”.

It is also known for a serpentine / convoluted conduit (but without aerofoils) to be used in stator vane cooling mechanisms. An example of such a cooling mechanism is described in US6,241 ,467 “Stator vane for a rotary machine”.

However, none of the prior art devices may be applied to augment the forward thrust of a vehicle.

SUMMARY OF THE INVENTION

According to a preferred embodiment of the invention, there is provided a thrust device that includes: a non-linear elongate conduit that defines: a first axial portion that defines an axial inlet; a second axial portion that extends from the first axial portion of the conduit, wherein the longitudinal axis of the second axial portion is substantially orthogonal to the axis of the conduit axial inlet; and at least one first aerofoil disposed within the second axial portion of the conduit, wherein the at least one first aerofoil is configured or arranged such that an airstream traveling from the conduit axial inlet along the conduit and over the at least one first aerofoil induces a force substantially parallel to the axis of the conduit axial inlet.

Typically, the thrust device further includes a vehicle to which the conduit is secured.

Generally, the axis of the conduit axial inlet is substantially parallel to the intended forward travel of the vehicle.

Preferably, the at least one first aerofoil is arranged such that the force that is, in use, induced by the at least one first aerofoil is substantially in the direction of forward travel of the vehicle.

Typically: the conduit is serpentine in shape, defining: a third axial portion operatively downstream the second axial portion of the conduit, which third axial portion is curved; and a fourth axial portion operatively downstream of the third axial portion of the conduit, wherein: the longitudinal axis of the fourth axial portion is substantially orthogonal to the axis of the conduit axial inlet; and at least one second aerofoil is disposed within the fourth axial portion of the conduit.

Generally, the at least one second aerofoil is configured or arranged such that the force that is, in use, induced by the at least one second aerofoil is substantially in the direction of forward travel of the vehicle.

Preferably, the thrust device further includes guide vanes within the conduit between the at least one first aerofoil and the at least one second aerofoil. More specifically, the guide vanes may be disposed at conduit bends, operatively upstream of: the at least one first aerofoil; and the at least one second aerofoil.

Typically: the axial cross-sectional area of the second axial portion of the conduit is less than the axial cross-sectional area of the conduit axial inlet; and the axial cross-sectional area of the fourth axial portion of the conduit is less than the axial cross-sectional area of the second axial portion of the conduit.

Generally, the conduit defines an outlet operatively downstream of the at least one second aerofoil.

Preferably, the thrust device further includes a swivel disposed along the conduit, which swivel permits relative rotation of portions of the conduit on either side of the swivel.

Optionally, the thrust device further includes a transition portion along the conduit, which transition portion reduces the axial cross-sectional area of the conduit, and wherein the axis of the transition portion is either orthogonal to or parallel to the axis of the conduit axial inlet. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of examples only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a thrust device according to a first embodiment of the invention;

Figure 2 is a partially cut-away perspective view of a section of the thrust device in Figure 1 including first and second axial portions of the conduit;

Figure 3 is a partially cut-away perspective view of a section of the thrust device in Figure 1 including third, fourth and fifth axial portions of the conduit;

Figure 4 is a partially-cut-away top view of a thrust device according to a second embodiment of the invention;

Figure 5 is a partially cut-away top view of a thrust device according to a third embodiment of the invention; and

Figure 6 is a partially cut-away top view of a thrust device according to a fourth embodiment of the invention.

DESCRIPTION OF THE INVENTION

With reference to Figures 1 to 3, a thrust device 10 according to a first embodiment of the invention includes a conduit 12 and aerofoils 14 disposed within the conduit 12.

The conduit 12 is non-linear and divided into five axial portions 12a, 12b, 12c, 12d and 12e. More specifically, the conduit 12 is convoluted or (more accurately) serpentine in shape. A first axial end of the conduit 12 (at an axial end of the first axial portion 12a of the conduit 12) is open, defining a conduit 12 axial inlet 16. A second axial end of the conduit 12 (at an axial end of the fifth axial portion 12e is similarly open, defining a conduit 12 outlet 18. The conduit 12 permits fluid communication there along from its axial inlet 16 to its axial outlet 18.

The conduit 12 includes:

• a first axial potion 12a that: defines an axial inlet 16 at a first axial end of the conduit 12; and bends / curves and extends from the axial inlet 16, reducing the axial cross-sectional area of the conduit 12;

• a second generally linear axial portion 12b that extends from the first axial portion 12a;

• a third axial portion 12c that bends / curves and extends from the second axial portion 12b, further reducing the axial cross-sectional area of the conduit 12;

• a generally linear fourth axial portion 12d that extends from the third axial portion 12c; and

• a fifth axial portion 12c that bends / curves and extends from the fourth axial portion 12d to the conduit 12 outlet 18 at the second axial end of the conduit 12.

A transition portion 22 is disposed between the second portion 12b of the conduit 12 and the third portion 12c of the conduit 12, which transition portion 22 reduces the axial cross-sectional area of the conduit 12 at a greater rate than the rest of the conduit 12.

The conduit axial inlet 16 defines an axis A-A.

Referring to Figures 1 and 2: the first axial portion 12a of the conduit 12 extends from the conduit 12 axial inlet 16, bending / curving between 60 and 90 degrees, preferably between 80 and 90 degrees; and the generally linear second axial portion 12a extends from the first transition portion 24 of the conduit 12 and defines a longitudinal axis B-B that is substantially orthogonal to the axis A-A of the conduit 12 axial inlet 16.

In this specification, “substantially orthogonal” is intended to mean that the longitudinal axis B-B is angularly offset relative to the axis A-A by between 75 and 105 degrees.

The axial cross-sectional area of the conduit 12 decreases along its length from the conduit 12 axial inlet 16 to the conduit 12 axial outlet 18, in use, to increase the airspeed within the conduit 12. More specifically: (i) the axial cross-sectional area of the second axial portion 12b of the conduit 12 is less than the axial cross- sectional area of the conduit 12 axial inlet 16; and (ii) the axial cross-sectional area of the fourth axial portion 12d of the conduit 28 is less than the axial cross-sectional area of the second axial portion 12b of the conduit 12. In use, the reducing axial cross-sectional area of the conduit 12 increases the airspeed within the conduit 12, making the aerofoils 14 more efficient as the aerofoils 14 are spaced further along the conduit 12 away from the conduit 12 axial inlet 16.

Turning to Figures 1 and 3: the third axial portion 12c of the conduit 12 bends / curves between 60 and 90 degrees, preferably between 80 and 90 degrees; and the generally linear fourth axial portion 12d extends from the third axial portion 12c of the conduit 12 and defines a longitudinal axis C-C that is substantially orthogonal to the axis A-A of the conduit 12 axial inlet 16.

A series of four first aerofoils 14a are disposed within the second axial portion 12b of the conduit 12, and a series of five second aerofoils 14b are disposed within the fourth axial portion 12d of the conduit 12.

Each of the first and second aerofoils 14a and 14b are arranged such that an airstream traveling from the conduit 12 axial inlet 16 along the conduit 12 and over the first and second aerofoils 14a and 14b induces a force substantially parallel to the axis A-A of the conduit 12 axial inlet 16. More specifically, in respect of each of the first and second aerofoils 14a and 14b, the surface of the aerofoil proximal the conduit 12 axial inlet 16 is curved, whereas the surface of the aerofoil distal the conduit 12 axial inlet 16 is planar.

The conduit 12 (with aerofoils 14) is secured to a vehicle (not shown) (e.g. a car, truck, plane, train, boat), with the axis A-A of the conduit 12 axial inlet 16 substantially parallel to the intended forward travel of the vehicle. More specifically, the conduit 12 axial inlet 16 is arranged to face the intended forward travel of the vehicle, such that forward travel of the vehicle causes fluid (for example, air) to ram into the conduit 12 axial inlet 16. This rammed fluid travels along the conduit 12, over the aerofoils 14, which induces a force substantially in the direction of forward travel of the vehicle, augmenting the forward thrust of the vehicle.

In this specification, “substantially in the direction of forward travel of the vehicle” is intended to mean angularly offset relative to the direction of forward travel of the vehicle by less than 15%, preferable by less than 10%.

Typically, the conduit 12 is supported by a frame (not shown), which frame is secured to a vehicle. Furthermore, the aerofoils 14 are typically also secured to the frame via links that extend through the conduit 12 wall. Each link is generally connected to its corresponding aerofoil 14 30% behind the leading edge of the aerofoil 14. Furthermore, the outer surface of the conduit 12 could define strengthening ribs.

A thrust device 110 according to a second embodiment of the invention is shown in Figure 4. The thrust device 110 according to the second embodiment of the invention is similar to the thrust device 10 according to the first embodiment of the invention. However, the transition portion 122 is substantially axially aligned with the axis C-C of the fourth portion 112d of the conduit 112 instead of the third portion 112c of the conduit 112. It will be appreciated that constriction by the transition portion 122 of fluid flowing along the conduit 112 from the conduit axial inlet 116 to the conduit axial outlet 118 imposes a net axial force upon the transition portion 122 in the direction of the constriction. Whereas, the transition portion 22 of the thrust device 10 according to the first embodiment of the invention creates a net axial force substantially opposite to the intended forward direction of travel of the vehicle, the transition portion 122 of the thrust device 110 according to the second embodiment of the invention creates a net axial force substantially orthogonal to the intended forward direction of travel of the vehicle, thereby not detracting from the net forward force generated by the thrust device 110.

The thrust device 110 further includes a swivel 124 that enables relative rotation of the third portions 112c of the conduit 112 on either side of the swivel 124.

Furthermore, the thrust device 110 includes guide vanes 126 disposed between the sets of aerofoils 114a and 114b, which guide vanes 126 facilitate fluid flow / smooths fluid flow along the bends between: the first portion 112a of the conduit 112 and the second portion 112b of the conduit 112; and the third portion 112c of the conduit 112 and the fourth portion 112d of the conduit 112. More specifically, guide vanes 126 are disposed at conduit 112 bends, operatively upstream of: the first set of aerofoils 114a; and the second set of aerofoils 114b.

A thrust device 210 according to a third embodiment of the invention is shown in Figure 5. The thrust device 210 according to the third embodiment of the invention is similar to the thrust device 110 according to the second embodiment of the invention. However, instead of being serpentine in shape, the conduit 212 of the thrust device 210 according to the third embodiment of the invention is in the form of a loop. As with the thrust devices 10 and 110 according to the first and second embodiments of the invention, the aerofoils 214 are in portions of the conduit 212 that are axially aligned substantially orthogonally to the axis of the conduit inlet 216.

Furthermore, the axis D-D of the transition portion 222 of the thrust device 210 according to the third embodiment of the invention is substantially parallel to the axis A-A of the conduit inlet 216. It will be appreciated that, in use, constriction by the transition portion 222 of fluid flow along the conduit 212 from the conduit axial inlet 116 to the conduit axial outlet 118 creates a net axial force substantially in the direction of forward travel of the vehicle. The thrust device 210 similarly includes a swivel 224 that enables relative rotation of the conduit 212 portions on either side of the swivel 224. A thrust device 310 according to a fourth embodiment of the invention is shown in Figure 6. The thrust device 310 according to the fourth embodiment of the invention is similar to the thrust device 210 according to the third embodiment of the invention, but with the portions of the conduit 312 on either side of the swivel 324 rotated relative to each other by 180 degrees. The thrust device 310 according to the fourth embodiment of the invention also includes first and second transition portions 322a and 322b. The first transition portion 322a of the thrust device 310 according to the fourth embodiment of the invention is arranged with its axis E-E substantially orthogonal to the axis A-A of the conduit inlet 316, such that, in use, constriction by the first transition portion 322a of fluid flow along the conduit 312 from the conduit axial inlet 316 to the conduit axial outlet 318 creates a net axial force substantially orthogonal to the the direction of forward travel of the vehicle; whereas, the second transition portion 322b is arranged with its axis F-F substantially parallel to the axis A-A of the conduit inlet 316, such that, in use, constriction by the second transition portion 322b of fluid flow along the conduit 312 from the conduit axial inlet 316 to the conduit axial outlet 318 creates a net axial force substantially in the direction of forward travel of the vehicle.