GB2349671A - Gas turbine having rotating mixing chambers and helical flow - Google Patents

Abstract

A gas turbine engine has a centrifugal compressor 10 on which is mounted an annular fuel ring 13. Liquid fuel delivered by pipe 18 is centrifuged and atomised trough fuel holes 16 into rotating mixing chambers 14 defined between compressor blades (11, fig 2) and shroud 12. The air fuel mixture moves in a helical path around the engine's axis trough an annular chamber 6 where it is ignited by igniter 19 and guided by vanes 21. Optionally, gas fuel may be added via fuel port 24, also in a helical path. A turbine 20 is rotated by the helical path of the expanding gas, guided by vanes 20B,20C. Air may be introduced into port 22 to start the engine. It is stated that the net force on blade and vanes 20A,20B,20C,21 gives forward trust to the engine.

Description

Title : Prime Mover The present invention relates to a novel gas turbine prime mover such as an engine.

All gas turbine engines operate on a similar principle of compressing air through one or more rotating compressor blades and feeding the compressed air into one or more static mixing chambers in the engine body into which fuel is injected. The air/fuel mixture is then ignited in a combustion chamber and the resulting expanding gases are channelled generally parallel to the rotating axis of blades, in a straight path through turbine blades to an exhaust port.

The expanding gases rotate the turbine blades, which in turn rotate the compressor blades.

A number of difficulties exist with these known engines. One such difficulty is that entry vanes are required to angle the direction of flow across the turbine blades, and then exit vanes are required to straighten the flow of gases to the exit port after flowing over the turbine vanes.

These entry and exit vanes create a drag on the gas flow leading to inefficiencies.

The invention seeks to provide an improved novel gas turbine prime mover such as an engine.

According to the present invention there is provided novel gas turbine prime mover comprising: a) A prime mover core body, b) An outer casing surrounding the core body, c) An annular chamber between the core body and the outer casing d) A rotating air compressor having a plurality of blades to direct and compress air radially outwards to the tips of the blades, each of said blade tips defining a mixing chamber which rotates with its blade, e) A means to inject liquid fuel into each of said mixing chambers to mix with the compressed air, said rotating mixing chambers expelling air and fuel mixture in a helical path down the annular chamber. f) A means to inject gas fuel into the combustion annular chamber, where it mixes with the compressed air expelled from said mixing chambers in a helical path down the annular chamber g) At least one igniter in said annular chamber to ignite fuel and air therein to provide an expanding gas following a helical path. h) A turbine in the annular chamber on the side of the igniter remote from the compressor, said turbine being adapted to be rotated by the helical path of the expanding gas and connected to rotate the air compressor, and central axial drive shaft. i) An exhaust port for said expanding gas passing the turbine blades.

Preferably a plurality of thrust vanes are provided in the annular chamber connected to the core body and/or outer casing, said vanes, when subjected to the helical path of the expanding gases, providing lift to impart a force of thrust on the core body and/or outer casing in the direction of the compressor. Preferably at least some vanes pivot to accommodate changes in the shape/direction of the helical path of the expanding gases so as to obtain maximum lift/thrust.

The vanes may be aerofoil in shape. In one embodiment three rows of thrust vanes are provided.

Preferably the compressor blades carry an annular fuel ring, the outer surface of which provides a wall to the mixing chambers. Preferably the annular ring has a plurality of annular holes entering each mixing chamber through which fuel is injected into each mixing chamber.

In one embodiment the annular fuel ring inclues an internal circumferential groove which provides a fuel line to each hole. The fuel ring may rotate about a projection on the core body, the internal groove and projection providing a fuel line to each hole.

Preferably a plurality of turbine guide vanes are provided on one or both sides of the turbine Blades, said guide vanes, when subjected to the helical path of the expanding gases, providing lift to impart a force or thrust on the turbine in the direction of the compressor.

Some vanes may pivot to accommodate changes in the shape of the helical path of the expanding gases so as to obtain maximum lift. The vanes may be aerofoil in shape.

Preferably a port is provided in the outer casing to apply gas such as air to the turbine blades to start the engine.

Preferably a port is provided in the outer casing to apply gas fuel such as natural gas/methane as an alternative option to liquid fuel.

The invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a schematic cross section view of a gas turbine engine.

Figure 2 shows a perspective view of the compressor blades of the engine of Figure 1 with a shroud mostly omitted.

Figure 3A shows a schematic view of the turbine and its guide vanes of Figure 1.

Figure 3B shows a schematic view of a known turbine.

Referring to Figure 1 there is shown a gas turbine engine I having a front air intake port 2 and an exhaust 3. Engine 1 has a main generally, cylindrical, core body 4 to support the engine components. Around the core body 4 is an outer tubular casing 5 which may be double skinned as shown with a honeycomb sandwich 5A between the skins. Casing 5 is spaced from the core body 4 to create an annular chamber 6 (combustion area) between the core body and the outer casing.

Core body 4 has a central cylindrical cavity 4A which supports a drive shaft 7 which rotates in bearings 8A, 8B, 8C, 8D. A spinner 9 is mounted on the front of the shaft 7.

An air compressor 10 with back plate lOA is mounted for rotation on shaft 7.

Compressor 10 has a plurality of blades 1 I to direct, when rotated, air radially outwards to the tips of the blade. A front shroud 1 2 is mounted to rotate on the outer edges of the blade tips (only partially shown in Figure 2). An annular fuel ring 13 is mounted to rotate on the inner edges of the blade tips. The spaces between the tips of the blades each define a mixing chamber 14, which rotates with its blades, with the shroud and fuel ring also providing walls to each mixing chamber.

In Figure 2 there are shown fourteen blades I I on the compressor so that there will be fourteen rotating mixing chambers 14. The number of mixing chambers may be increased or decreased with the number of blades 11.

Fuel ring 13 has an internal annular circumferential groove 15 and twenty four holes 16 in the outer wall of the fuel ring to inject liquid fuel into each of said mixing chambers 14. The said holes 16 combined cross-sectional area is equal to the cross-sectional area of the liquid fuel pipe 18.

Annular fuel ring 13 rotates about a narrowed diameter projection 4B on the core body 4 The said projection supports a fuel pipe 18 which delivers optional liquid fuel into the circumferential grove 15 of the fuel ring. As the fuel ring 13 rotates, the optional liquid fuel is centrifuged through the fuel holes 16 and into the mixing chambers 14.

A gas fuel port 24 is mounted through the outer casing 5 to inject optional gas fuel directly into the annular combustion area 6 immediately behind the mixing chambers 14, in a helical flow path in the same direction as the compressed air expelled from the rotating mixing chambers 14.

In operation of the engine, air from the inlet port 6 is drawn into the compressor blades lu, and air is forced outwards by the rotation of the blades into the mixing chambers 14 where air is mixed with the optional liquid fuel supplied by the fuel ring 13 The air fuel mixture is expelled from the mixing chambers in a generally helical path as the mixing chambers are themselves rotating, the axial speed imparted by the centrifugal action of the compressor and the rotational speed due the speed of rotation of the blades.

The optional gas fuel is injected by fuel port 24 directly into the combustion area 6 to follow the same helical path as the expelling compressed air from the mixing chambers.

An igniter 19 is provided in said annular chamber 6 to ignite fuel and air therein to provide an expanding gas which travels in a helical path down the annular chamber 6 A turbine 20 is provided in the annular chamber 6 on the side of the igniter 19 remote from the compressor 10.

The turbine 20 is adapted to be rotated by the helical path of the expanding gas and connected through the shaft 7 to rotate the air compressor 10. As shown in Figure 3A, turbine 20 includes a plurality of turbine blades 20A, entry guide vanes 20B and exit guide vanes 20C. The blades and vanes are aerofoil in shape. The helical path of expanding gases is shown by the arrow A.

The entry guide vanes 20B, when subjected to the helical path of the expanding gases, provide lift to impart a force or thrust on the turbine 20 in the direction of the compressor as shown by arrows B (these entry guide vanes may be designed to pivot to accommodate changes in the shape of the helical path of the expanding gases so as to obtain maximum lift/thrust).

The entry guide vanes direct the gas flow across the turbine blades 20A to provide a rotational force shown by arrow C, as well as a force or thrust on the turbine in the direction of the compressor as shown by arrow D. The exit guide vanes 20C converts the helical flow of gas into a linear direction as shown by arrow E to direct the gas flow to the exhaust port 3, but provide a drag force as shown by arrow F. The net force however of the blades 20A, 20B and 20C is one of thrust in the direction of the compressor towards the front of the engine.

Figure 3B shows the vanes of a turbine in a known type of engine subjected to a linear axial flow of expanding gas Here the entry guide vanes and exit guide vanes create a drag force, with the turbine blades providing a thrust force, but the net force however of the blades 20A, 20B and 20C is one of drag in the direction away from the compressor towards the rear of the engine.

Three rows of thrust vanes 21 are provided in the annular chamber connected to the core body which when subjected to the helical path of the expanding gases, providing lift to impart a force or thrust on the core body and/or outer casing in the direction of the compressor in the same manner as entry vanes 208. Again at toast some thrust vanes may pivot to accommodate changes in the shape of the helical path of the expanding gases so as to obtain maximum lift. The vanes may be aerofoil in shape.

A port 22 is provided in the outer casing to apply gas such as air to the turbine blades to start the engine.

A port 24 is provided in the outer casing to allow the use of optional gas fuel's to be use as an alternative to liquid fuels.

The ability of the thrust vanes and the turbine entry vanes to obtain thrust from the helical path of expanding gases leads to efficiencies in the engine compare to known gas turbine engines.

The air mass follows a helical path in relation to the axis and a linear path in relation to the rotating mixing chambers. The relative speed of the air mass with regard to the rotating mixing chamber is only linear speed (for friction purposes), and thus the internal gas flow friction is very low compared to conventional designs.

The main advantage of the rotating fuel ring, is the ability to achieve high spray pressure without the need for complex pumps and metering equipment, and thus achieve good atomisation and fast burning without smoke. This design also gives a flame with a variable area and a much higher area/volume ratio than a conventional burner. This should give better acceleration and more effective mixing of hot and cold gasses.

The fueUair mixture having been ignited, heats up and rapidly expands, accelerating its already high momentum helical path. It will also be noted that the rotational speed of the mass of airflow is such that the thrust vanes'alteration of the helical path angle is minimal, thus maintaining the rotational momentum.

The prime mover of the invention could be other than an engine, e. g. a compressor, a generator or other type of prime mover.

Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Drawings Key 1. Engine 2. Air intake port 3. Exhaust 4. Core body 4A. Central cylindrical cavity 5. Outer tubular casing 5A. Honeycomb sandwich 6. Annular combustion chamber/area 7. Drive : 8A. Bearing 8B. Bearing 8C. Bearing 8D. Bearing 9. Spinner 10. Air compressor 1 osa. Air compressor back plate i 1. Compressor Blades 12. Front shroud 13. Annular fuel ring 14. Fuel/Air mixing chamber 15. Circumferential grove in fuel ring 16. Holes in fuel ring 17. Fuel ring back plate 18. Liquid fuel pipe 19. Igniter 20A. Turbine 20B. Turbine entry vanes 20C. Turbine exit vanes 21. Thrust vanes/Gas flow guide vanes set in rows following a helical path 22. Compressed gas inlet port (for engine starting) 23. Guide vanes 24. Gas fuel inlet port 25. Exhaust cone A Gas flow into Turbine (Fig. 3A-Helical Path. Fig. 3B-Axial Path) B'Lift force'generated by Turbine Entry Vanes (Fig. 3A=Thrust. Fig. 3B=Drag) C'Turning Force'generated by Turbine D Effective reaction of force generated by Turbine Blades E Gas flow to exhaust-Axial flow F Force generated by Turbine Exit Vanes = Drag

Claims (10)

1. CLAIMS 1. A gas turbine prime mover such as an engine, compressor or generator, comprising a roughly cylindrical body and a means of compressing air and forcing the air mass to follow a helical flow path around and along the body axis.
2. 2. A gas turbine prime mover as claimed in 1 wherein guides are provided to maintain the air mass's helical flow path around and along the body axis.
3. 3. A gas turbine prime mover as claimed in any preceding claim wherein a means is provided to turn the airflow from a rotating radial flow to an axial flow whilst maintaining its rotation in relation to the body axis.
4. 4. A gas turbine prime mover as claimed in any preceding claim wherein vanes are provided to produce a thrust force along the body axis as an air mass following a helical path around and along the body axis, flows past the said vanes.
5. 5. A gas turbine prime mover as claimed in any preceding claim wherein a means is provided for accelerating a liquid fuel to a rotational speed to match that of an air mass rotating around the body axis and then introducing the liquid fuel as an atomised spray into the rotating air mass with zero relative speed.
6. 6. A gas turbine prime mover as claimed in any preceding claim wherein a means is provided of introducing a gas fuel such as natural gas/methane directly into an air mass rotating around the body axis.
7. 7. A gas turbine prime mover as claimed in any preceding claim wherein a turbine is provided, being adapted to be rotated by an air mass following a helical flow path around and along the body axis.
8. 8. A gas turbine prime mover as claimed in any preceding claim wherein guides are provided to direct an air mass following a helical flow path around and along the body axis onto a turbine and in doing so produce a thrust force along the body axis.
9. 9. A gas turbine mover as claimed in any preceding claim wherein an external port is provided to supply compressed gas directly onto the turbine.
10. 10. A gas turbine prime mover substantially as described herein with reference to Figures 1-3 of the accompanying drawings.