WO2008020757A1

WO2008020757A1 - Integrated reaction turbine engine/generator assembly

Info

Publication number: WO2008020757A1
Application number: PCT/NL2007/050405
Authority: WO
Inventors: Wilhelmus Petrus Jozef Visser; Mark Oostveen; Willibald Mattheus Petrus Ahout
Original assignee: Micro Turbine Technology B.V.
Priority date: 2006-08-18
Filing date: 2007-08-17
Publication date: 2008-02-21
Also published as: NL2000189C2

Abstract

The reaction turbine engine has a single rotor member co tnprising an inlet, compressor, heating chamber, which can be a combustion chamber, and turbine. The generator comprises a rotor part and a stator part. The rotor member of the reaction turbine engine comprises the rotor part of the generator. The generator's rotor can be also cooled by the working medium of the engine. Other measures, such an insulating separation and additional cooling ducts, can be also incorporated into the assembly. A further integration can be achieved by additionally exploiting the rotor and stator parts of the generator as a magnetic bearing for the entire assembly.

Description

Integrated reaction turbine engine/generator assembly

The present invention relates to a reaction turbine engine.

A reaction turbine engine is known, for example, from DE3318863. This engine is provided with a stationary casing, axial compressor, fuel-oxidizer mixing station, arrangements for a reaction space, reaction turbine and a generator. The engine has a complicated layout, occupies a lot of space and involves many components. It is also complex, as it has a stator and a rotor (including compressor stator and compressor rotor) and requires a series of fuel-oxidizer mixing arrangements. The generator is mounted on the rotational engine shaft and has no further integration with the engine.

FRl 091754 discloses a reaction turbine engine having a rotational shaft with bearings, which extends through a housing, and a generator provided on the other side of the housing. This system is also complicated and spacious.

PCT/NL2004/00144 of Micro Turbine Technology B.V. discloses a reaction turbine engine. Such reaction turbine engine can be provided with a combustion chamber or a heating chamber to supply heat from an external source to either compressed air, steam or other working medium. The heating chamber can comprise either a number of heating chambers, which are separate from each other, or a single annular heating chamber. In many cases, it is intended to couple such a reaction turbine engine with a generator for the generation of electricity. Herein, the output shaft of the reaction turbine engine is connected to the input shaft of the generator. These are placed relative to each other at a certain distance apart, when viewed in the direction of the shaft.

The aim of the invention is to provide a more compact design for a coupled assembly of a reaction turbine engine and a generator, which benefits from close integration.

This aim is realized in an integrated reaction turbine engine/generator assembly having the features of claim 1. A very compact and efficient design is, first of all, achievable due to the provision of the generator's rotor part on/in the rotor member of the reaction turbine engine and other integration solutions described below.

The reaction turbine engine will be generally turning at high rotational speeds (10,000- 100,000 r.p.m.) around its axis of rotation. It has been shown that a generator turning at the same high speeds can be structurally very compact. This applies, in particular, to generators in which permanent magnets are used. The small geometric envelope of such generators allows, for example, for a part of such a generator to be accommodated in the available space within the periphery of the rotor member of the described reaction turbine engine. Preferably, this is the space formed by the heating chamber, which can be a combustion chamber, and either at least one other component extending parallel to the axis of rotation or the axis of rotation itself. The generator can be accommodated either entirely or partially within this space. In this case, numerous options are possible for the embodiment of the generator. For instance, it is possible to realize the rotor as being the generator's outer structural part and the stator as being the generators' inner part. In such a case, the rotor is, preferably, structurally directly linked to the rotor member of the reaction turbine engine. The stator, which preferably comprises a coil in this case, lies substantially on the axis of rotation of the rotor member of the engine. Likewise, it is possible to choose an embodiment in which the rotor is being the generator's inner part and the stator being the outer part. Other options are also possible.

Generally, according to the invention, the rotor member does not have to be provided with stationary structural elements. However, if it is aimed to increase the output of the reaction turbine engine, it might be possible to provide stationary items, such as a structural element with vanes as part of the turbine.

In all cases, thermal separation can be provided between the rotor member of the engine and the generator. This thermal separation can comprise an insulating material, whether or not in combination with a cooling circuit.

Furthermore, air or other fluid entering the rotor member of the reaction turbine engine can be used as a cooling fluid for the generator.

Instead of the described generator with magnets in the rotor, any other generator known from the prior art may be used.

According to the further embodiment of the invention, the rotor part of the generator is provided on the inlet of the rotor member. To this end, this inlet can comprise an inlet duct, for example, extending substantially coaxially with the axis of rotation of the rotor member. The rotor part of the generator can be provided on such a duct having the stator part circumscribing such a rotor part.

According to a further alternative of the invention, the rotor part of the generator might be provided on the compressor of the rotor member. Preferably, this compressor extends substantially radially relative to the axis of rotation. The rotor part of the generator can be provided either on the front side (on the side of the inlet) of the compressor or on the back side thereof. Obviously, any combination of the compressor and inlet of the rotor member can be used to support the rotor part of the generator. The stator part of the generator can be positioned correspondingly.

It is possible to provide the reaction turbine engine and/or the generator with bearings. Since the rotor member of the engine supports the generator's rotor part, such bearings will be common for both the rotor member and the generator. The bearings can be of various types, such as roller bearings, magnetic bearings, etc.

According to the invention, it is also possible to have the generator's rotor and stator parts comprising a magnetic bearing for the reaction turbine engine/generator assembly.

The invention also relates to a heating system in which the above-described integrated reaction turbine engine/generator assembly is used. Such a heating system can comprise a boiler. The integrated reaction turbine engine/generator assembly is accommodated in or next to such a heating boiler and the heat emanating therefrom is used to heat water or some other heating medium. The generated electric power can be used at the site where the heating boiler is installed or can be delivered back to the mains.

In particular, such an integrated reaction turbine engine/generator assembly is attractive when used in combination with a water heater. After all, hot water is demanded throughout the year, so that such a reaction turbine engine can be effectively operative all year long.

In order to enhance the output, efficiency, cooling of the structure and/or reduce the emission of undesirable chemicals in the exhaust, it may be desirable to inject water into the working cycle of the engine. In the embodiment in which a boiler is used, this water can be the condensed water formed during the condensation of the flue gases.

The invention will be illustrated in greater detail below with reference to an illustrative embodiment represented in the drawing, in which:

Fig. 1 shows diagrammatically an integrated reaction turbine engine/generator assembly according to the present invention in front view;

Fig. 2 shows the assembly according to Fig. 1 in cross section;

Fig. 3 shows a variant of the assembly according to Fig. 2 in cross section;

Fig. 4 shows a reaction turbine engine working on steam in cross section;

Fig. 5 shows a further alternative of an integrated reaction turbine engine/generator assembly according to the invention; and Fig. 6 shows yet another alternative of the invention.

In Fig. 1 and 2, a reaction turbine engine, according to the invention, is denoted by 1. It comprises a rotor member 2 having an axis of rotation 70. It can be seen from Fig. 2 that the rotor member is provided with an inlet 3 - intaking air, for example - and a radial compressor 41. Connected thereto is a heating chamber 4 - which is a combustion chamber in this embodiment - followed downstream by a reaction turbine 5 with jet nozzles 6. According to an advantageous embodiment of the invention, the combustion chamber 4 is realized as a single annulus. It is important to appreciate, however, that it is also possible to provide a number of combustion chambers.

A combustible mixture is ignited in the combustion chamber by the ignition system 22- 23 comprising a spark plug 22. After this, the combustion process can sustain itself.

A generator 7 is present, comprising an outer rotor part 8 and an inner stator part 11. The rotor part 8 is connected to the wall of the combustion chamber 4 and comprises a number of permanent magnets. Measures may possibly be taken to prevent excessive heat transfer between these two parts, such as the fitting of an insulation 26.

The stator part 11 comprises a number of coils 12 wound around a lamination stack and fitted to the stationary shaft 10.

During operation, the shaft 10 will be stationary. The rotor member 2, integrated with the generator's rotor part 8, will rotate around the shaft 10 supported by a bearing 42.

In Fig. 3, a variant of the above is shown in which the generator is accommodated in the space 28. Herein, the rotor member has a shaft 10 on which the rotor part of the generator, comprising permanent magnets 40, is fitted. The stator part 39, fixedly connected to the surroundings, is fitted between the rotary heating chamber 4 and the rotary magnets 40. It is provided with a number of coils 38.

The permanent magnets 40 and coils of the stator part 39 function as a magnetic bearing supporting both the rotor member and the generator's rotor part.

In Fig. 4, a variant of the invention is presented in which the generator 19 is accommodated in the space 29, and in which the heating chamber 16 is an evaporation chamber. A fluid, such as some liquid, is supplied from a container 14, via a suction pipe 13 into the compressor embodied as a pump impeller 15. After this, evaporation takes place in the chamber 16 by the virtue of an external heat transfer, denoted diagrammatically by the arrow 17. The jet nozzles 18 ensure the rotational motion of the rotor member. In this embodiment, just as in Fig. 1 and 2, the generator's rotor part 20 is fitted such that it lies close to the wall of the chamber 16. In this case, however, a space for cooling ducts 21 is present between the rotor part 20 and this wall. In this example, the generator's stator part is accommodated in the centre of the structure, denoted by 24, and comprises coils 25.

As alternative to the above embodiments, it is possible to arrange the generator at the inlet side of the rotor member. In such a case, it is possible to have a flow of inlet fluid, such as intake air, pass either along the rotor part or stator part of the generator in order to provide cooling.

Fig. 5 shows a further embodiment of the integrated reaction turbine engine/generator assembly according to the invention. In this embodiment, the inlet 43 of the rotor member of the reaction turbine engine 44 comprises a duct 45 on which the rotor part

46 of a generator 71 is provided. The generator's stator part is indicated by 47. In this embodiment the stator part is a coil, whilst the rotor part is a permanent magnet.

However, it has to be understood that any combination of coils and/or (permanent) magnets can be used for both the stator and the rotor part.

The flow of the reaction turbine engine's inlet 43 also serves as the cooling flow of the generator 71.

In Fig. 5, the bearing supporting the rotor member 44 is a magnetic bearing realized by the combination of the generator's rotor 46 and stator 47 parts. Obviously, a more conventional bearing can be used.

Fig. 6 shows a further embodiment of the integrated reaction turbine engine/generator assembly, wherein the reaction turbine engine 54 comprises an inlet 49, compressor 50, heating chamber 51 and turbine 52. At the front side of the compressor, pointed towards the inlet 49, the rotor part 56 of a generator 55 is provided. Next to it, correspondingly, the stator part 57 is present. In this case, the rotor part 56 is a magnet, whilst the stator part 57 is a coil. Besides, these items can be used in any other combination, as indicated above with reference to Fig. 5. The same applies to the bearing system. Cooling of the generator's rotor, in this case, is provided mainly by the air flowing through the compressor 50.

A space 58 is provided between the heating chamber 51 and the axis of rotation 70. It is possible to fit the generator in this space (58) - in a way comparable to what is shown in Figs. 1-4. However, contrary to Figs. 1-4, the generator's rotor will still be provided on the compressor. That is to say, both the rotor and the stator parts of the generator can be placed on the other side of the compressor 50 with respect to the embodiment in Fig. The reaction turbine engines which are shown here can be fitted with their axis of rotation 70 in any desired position. Moreover, they could be used for further applications. One of the applications is for the use in combination with a heating boiler, which is used either to provide hot water for a central heating system or to provide hot water for such consumption purposes as shower, bath, kitchen and the like. If the flue gases experience condensation, the water in the condensate can be used for the injection into the working cycle of the engine. This contributes to a higher output, efficiency, promotes cooling and lowers the temperature in the combustion chamber, thereby reducing the emission of undesirable chemicals.

It has been also demonstrated that the output of the reaction turbine engines shown here can be increased by varying the quality of the fuel. Particularly, a higher output can be obtained by using low calorific value fuels, which require higher flows for the same heat input. For the same fuel flow, the efficiency of the reaction turbine engine can be increased by using low calorific value fuels due to the lower jet velocities in the nozzles resulting from the lower working temperatures. It is important to appreciate that this method can be implemented independently of the measures described above.

After reading the above, for the persons skilled in the art, further modifications will be obvious and are within the scope of the appended claims.

Claims

1. Integrated reaction turbine engine/generator assembly, wherein the reaction turbine engine comprises a single rotor member having an inlet, compressor, heating chamber and turbine, and wherein said generator has a rotor part and a stator part, characterized in that said rotor member comprises said rotor part.

2. Assembly according to claim 1, wherein the rotor member of the reaction turbine engine comprises a portion of its structure located off the axis of rotation of the rotor member, so that a space exists between this portion and the axis of rotation, and the generator is fitted into this space.

3. Assembly according to one of the preceding claims, wherein said rotor and stator parts of the generator comprise a magnetic bearing for said assembly.

4. Assembly according to one of the preceding claims, wherein said rotor part of the generator is provided on said inlet on the reaction turbine engine.

5. Assembly according to one of the preceding claims, wherein said rotor part of the generator is provided on the outer surface of one of the sides of said compressor of the reaction turbine engine.

6. Assembly according to one of the preceding claims, wherein the rotor part of the generator has a heat exchanging contact with a surface of said reaction turbine engine, thereby exchanging heat with the working medium of said reaction turbine engine.

7. Assembly according to one of the preceding claims, wherein said heating chamber comprises a combustion chamber.

8. Assembly according to one of the preceding claims, wherein a water injector into the working cycle of said reaction turbine engine is provided.

9. Assembly according to one of the preceding claims, wherein said rotor part comprises a permanent magnet.

10. Assembly according to one of the preceding claims, wherein an insulating partition wall is provided between said generator and said reaction turbine engine.

11. Assembly according to one of the preceding claims, wherein a cooling duct is provided between said generator and said reaction turbine engine.

12. System comprising a heater boiler and an integrated reaction turbine engine/generator assembly according to one of the preceding claims.

13. System according to claim 12, comprising a water heater, wherein heat extracted from the reaction turbine engine is supplied to the water heater.

14. System according to claim 12 or 13, wherein the condensed water in the flue gas is used for said water injection.