WO2008020758A1

WO2008020758A1 - Reaction turbine engine

Info

Publication number: WO2008020758A1
Application number: PCT/NL2007/050406
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: NL2000188C2

Abstract

Reaction turbine engine (1,21,41) with additional compressor. The reaction turbine engine comprises a rotor member (2,22,42), which has an inlet (95,97), a compressor (10,23,50), a heating chamber (11,31,51) and a turbine (12,28,62). The heating chamber can be a combustion chamber. It is proposed to integrate an additional compressor (3,53) upstream the inlet in order to increase the output and efficiency of such a reaction turbine engine. This additional compressor has a rotor part (13,63) and a stator part (14,64). The rotor part is coupled with the rotor member (2,22,62) of the reaction turbine engine and turns at the same rotational speed with it. The working medium is brought from the additional compressor to the inlet of the engine's rotor member through a stationary conduit (9,69) with a sealing element. An electric generator (4) can be coupled with the reaction turbine engine. Besides, the residual heat in the engine exhaust can be profitably employed in a heating system. Therefore, a reaction turbine engine implemented in this way can be used for power generation (such as electric power) in various systems, as well as for combined power and heat generation (e.g. in central heating systems, auxiliary heaters, etc.). Besides, the engine is suitable for both stationary and mobile applications.

Description

REACTION TURBINE ENGINE

The present invention relates to a reaction turbine engine according to the preamble of claim 1. Such a reaction turbine is known, for example, from PCT/NL2004/000144. In this application, a very compact reaction turbine engine is described, which has a number of possible applications: For instance, generation of electric power and combined heat and power generation, wherein the residual heat in the exhaust gas is profitably used in a heating system. Depending on the application, a specific output of the reaction turbine engine is aimed at.

From FR-2680385 Al, a reaction turbine engine is known having an upstream axial compressor. This axial compressor turns at a rotational speed which differs from the rotational speed of the reaction turbine. The pressure ratio of an axial compressor is relatively low and the design is complicated. GB1223999 discloses a thermodynamic engine having a single compressor positioned upstream of the inlet of a rotating module. The inlet is directly connected to the combustion chamber without any compressor between the inlet and the combustion chamber. That is to say, the rotating module does not have its own compressor. The air is admitted through a conduit into which the compressor discharges. This conduit is arranged around the axis of the rotating module.

Various thermodynamic machines comprising compressors in combination with reaction chambers for different applications are known from WO 02/059469 and WO 2005/033490. The aim of the present invention is to provide a reaction turbine engine which has a superior combination of output, output efficiency and cost efficiency compare to existing thermodynamic engines.

This aim is achieved in a reaction turbine engine having the features of claim 1. According to the invention, the rotor part, or impeller, of an additional radial compressor is coupled with the shaft of the reaction turbine engine. The additional radial compressor could be a complex module, which can though be effectively integrated into the reaction turbine engine according to the invention. It is possible thereby to obtain higher output and efficiency. By preferably fitting the rotor part of the additional compressor on the shaft of the rotor member of the reaction turbine engine, only little extra structural efforts are necessary. In general, such a shaft can be already present: for the generation of electric power, when an electric generator is combined with the reaction turbine engine.

The additional radial compressor described above should be considered as a separate module with respect to the rotor member of the reaction turbine engine, even though the rotor part of the additional compressor turns therewith.

In the rotor member, the line of the inlet compressor preferably extends substantially perpendicular to the rotation shaft. A maximum compression, and hence maximum output and efficiency, is thereby obtained. The line of the heating chamber can have any position with respect to the rotation shaft. When the line of the heating chamber extends substantially perpendicular to the rotation shaft, reduced friction losses (against the ambient atmosphere) can be achieved. Moreover, an additional radial compressor integrated with the rotor member, as described above, can be installed.

According to the invention, two compressors are provided. The first compressor is known as such from PCT/NL2004/000144 and comprises a compressor integral (embedded into) with the rotor member, between the inlet - near the axis of rotation thereof- and the heating chamber incorporated into the outer periphery of the rotor member. An additional compressor, stacked upstream of the first compressor, is provided according to the invention. This additional compressor, or booster, has a stator part and a rotor part. The stator part comprises a stationary casing and a preferably stationary diffuser. The rotor part comprises an impeller rotating together with the rotor member of the reaction turbine engine.

Through the use of an additional compressor, a higher pressure rise can be achieved in the working cycle. For example, if the pressure rise effected by the first compressor is about 2:1, through the use of an additional compressor this compression can be increased to 6:1 or higher.

Higher compression either results in a higher power output from the reaction turbine engine at the same rotational speed thereof or allows a lower rotational speed for the same power output. Slower rotation of the engine (by way of example, rotational speeds between 30,000 and 100,000 rpm are mentioned) provides a reduction in the windage losses, incurred by friction against the ambient atmosphere. Both higher output and reduction in windage losses result in a higher efficiency of the reaction turbine engine. According to the invention, the additional compressor has an axial inlet around the axis of rotation. The inlet configuration can be also radial.

The energy input into the working cycle of the reaction turbine engine can be effected through any known physical mechanism. One option is the combustion of fuel in air staged in the heating chamber, which is then implemented as a combustion chamber. Both fuel and air can be mixed into a combustible mixture upstream of the combustion chamber. For example, a premixed fuel and air mixture can be supplied through the engine inlet. It can be also advantageous to supply (at least partly) the fuel to the combustion space via a separate line. For this, a duct can be used which partially extends through the shaft of the reaction turbine engine. The ignition can be likewise initiated through the duct. Wide variations in the fuel/air ratio are possible as to optimise the performance of the reaction turbine engine. In addition, the structure can be cooled with a film of air.

It is also possible to supply external heat to the compressed air, as well as steam, in the heating chamber. In that case, no combustion takes place in the heating chamber. It will hence be appreciated that the term heating chamber is a general expression for a chamber in which an energy input (e.g. heat release, heat supply) is effected in one way or other. According to the present invention, it is possible to fit one or more heating chambers. A single heating chamber, when provided, is preferably arranged in an annular shape.

In general, a number of discharges will be present in the invention downstream the heating chamber. Each discharge can be provided with an outflow nozzle to impart rotation of the reaction turbine engine, i.e. the rotor member thereof. Whenever the reaction turbine engine is provided with an electric generator, this generator can be used to start up the engine. However, it is also possible to use compressed air for this purpose, which is supplied to the inlet of the additional compressor.

An increase in the engine output and efficiency can be obtained by supplying water or water vapour into the working cycle of the reaction turbine engine. This will also enhance cooling and result in lower temperatures in the combustion chamber. This, in turn, will substantially reduce the emission of NOx. Whenever the residual heat in the exhaust gas is used in a heating system, the water vapour in the exhaust can condense. The condensate can be then used for water injection.

Further gains in output and efficiency can be obtained by rotating the reaction turbine engine in the hot exhaust gases thereof. Thereby, windage losses (aerodynamic friction losses) will further decrease.

Whenever the usage of the reaction turbine engine in a heating system is implied, a central heating boiler installed in households or offices is envisaged. Through the use of the above-described reaction turbine engine with an electric generator, the output, and/or the economic value thereof, can be considerably increased, since the electric power can be generated relatively cheaply.

Another application of the reaction turbine engine according to the present invention is in auxiliary heaters in vehicles/craft/vessels (both/either towed and/or non-towed). Thus in lorries, heaters are generally present for the heating of the cabin during rest breaks. However, a constant cooling of the load space of the lorry is also often demanded. The prior art reveals the usage of an additional motor for this purpose. Through the use of the reaction turbine engine according to the present invention in combination with an electric generator, it is possible to provide, with a single appliance, both heating and electricity for cooling and the like. The same applies to vehicles/craft/vessels in which there is a demand for power for a refrigerator and other apparatus. This demand can be effectively met by the reaction turbine engine in combination with an electric generator.

The electric generator which is used is preferably of the type which is provided with a rotor part having permanent magnets. More particularly, a very compact generator is used, which can be located, at least partially, within the geometric envelope of the reaction turbine engine.

The additional compressor can comprise a multistage additional compressor. That is to say, further compressors can be installed upstream/downstream of the compressor which is described here. These can be of any known type which is practically applicable. The turbine section of the reaction turbine engine can comprise rotating nozzles, arranged in either a single row or multiple rows (two or more). Various nozzle shapes can be selected. In particular, the nozzles can be of the convergent-divergent shape (type). The rows of nozzles can be separated by passages in stationary baffle plates. The working medium can be also directed into a row of stationary vanes succeeded by a row of rotating blades. Either a single of multiple (two or more) rows of vanes and blades can be provided. Each combination of a row of nozzles and a row of passages, as well as a row of vanes and a row of blades, comprises a turbine stage. As follows from the above, the reaction turbine engine incorporates either a single- or multiple- stage turbine.

The baffle plates and stationary vanes mentioned above can be part of a stationary housing that may accommodate the reaction turbine engine. The presence of such a housing promotes safety, as it can serve as a containment for the debris in the case of a structural failure. The housing also contains high temperature expanded gases. This has an additional advantage of reducing the windage (friction) losses. As the housing is heated by the post-combustion gases, a heat exchanger can be structurally integrated with it. This allows to recuperate the residual heat in the expanded 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 in cross section a first variant of the present invention;

Fig. 2 shows diagrammatically a second variant of the invention; Fig. 3 shows a side view of a variant of the invention; and

Fig. 4 shows a rear view of the variant according to Fig. 3;

Fig. 5 shows a further embodiment of the invention;

Fig. 6 shows an example of a nozzle;

Fig 7. shows yet another embodiment of the invention.

In Fig. 1, a reaction turbine engine, according to the invention, is denoted by reference number 1. It comprises a rotor member 2. An additional compressor 3, or booster, is installed upstream. An electric generator is referred to by number 4.

The rotor member 2 comprises an inlet 95 followed by a compressor 10, the blades of which are schematically indicated by 96, and a heating chamber 11, which is a combustion chamber in this case. The chamber 11 is followed by a reaction turbine 12.

A central shaft 5 is present, which rotates around an axis 6. Installed on the shaft 5 is the impeller 13 of the additional compressor 3. The impeller is followed by a stationary diffuser 17. The latter can be of any known type, vaned or vaneless. The casing 14 in Fig. 1 is also stationary (details are not shown). The inlet of the additional compressor is denoted by 7, whilst the outlet is denoted by 8. Downstream of the outlet 8, there is a connecting duct or conduit 9, which can terminate in a sealing element (not shown in drawing) to seal the interface between the rotating and stationary structures. The inlet 95 is succeeded by the radial compressor of the rotor member 10 (the blades of which are denoted by 96). The discharges 12 can be provided with outflow nozzles (not represented in detail) functioning as a reaction turbine. The generator 4 has its rotor part mounted on the shaft 5. The generator's rotor preferably comprises a structure having permanent magnets, which is not shown in greater detail.

In the example shown in Fig. 1, a combustible mixture of fuel and oxidizer (e.g. air) is ingested through the inlet 7 and burns in the heating chamber 11 , being a combustion chamber in this example. In Fig. 2, mainly oxidizer is ingested through the inlet 7. The oxidizer contains either no fuel at all or only part of the required fuel. An auxiliary line 18 is present for the supply of more fuel, whether or not premixed with oxidizer. The line 18 is partially substantially concentric with the axis 6 and enters the combustion chamber 11 at the location 19. Ignition can be arranged in the combustion chamber itself. However, it is also feasible to ignite the mixture flowing through the line 18. Then, it will also act as an ignition source for the mixture in the combustion chamber 11. Besides, the use of the line 18 allows for the combustion in the combustion chamber to be better regulated.

It is possible to feed different fluids into the gas path of the reaction turbine engine. Instead of being liberated in combustion reactions, heat can be also supplied to the working fluid (medium) in the heating chamber from an external source. The impeller 13 according to the present invention can be realized in relatively small dimensions. In particular, it is smaller than 10 to 20 cm and, according to a preferred embodiment, is realized with a diameter of about 5-8 cm.

In Figs. 3 and 4, a second variant of the invention is presented. The reaction turbine engine is denoted by 21 and comprises a rotor member 22. The latter is provided with an inlet 27, to which a radial compressor 23 connects. Directly connected thereto is a heating chamber 31, which is followed by discharges 28 installed along the outer periphery of the rotor member. The rotation shaft is denoted by 26. Auxiliary fuel supply lines are denoted by 115. This construction, by virtue of a smaller surface area thereof, has lower windage (friction) losses. Upstream of this construction, the compressor shown above, with reference to Fig. 1 and 2, can be installed in the same way.

Figure 5 shows a further embodiment of the invention in cross section. The reaction turbine engine has reference number 41 and comprises a rotor member 42 with a structurally integrated inlet 97, radial bladed compressor 50, combustion chamber 51 and a turbine rotor 62 and 73. A generator 44 is also shown in the embodiment. It has a rotor part 98 and a stator part 99. The rotor part of the generator is integral with the shaft, marked by 55, aligned along the axis 56. The shaft 55 is connected to the rotor member 42 and the rotor of the additional compressor 53 (booster). The casing 64 of the additional compressor is stationary. The additional compressor (also embodied in the Fig. 1 and 2) has an inlet 57 and an impeller 63. The impeller is connected to the shaft 55. The impeller is followed by a stationary diffuser 67. The interface between the stationary discharge duct 69 and the rotating inlet 97 is sealed by a sealing element 68. According to the embodiment in Fig. 5, a stationary housing 70 is provided with a baffle plate incorporating flow passages 71 between the turbine rotor sections 62 and 73. The turbine rotor sections incorporate nozzles of preferred shape/type (e.g. convergent, convergent-divergent). The housing is also integrated with a heat exchanger 75 to recuperate the residual heat in the exhaust gases. Fig. 6 exemplifies an embodiment of the turbine nozzle 84, as can be incorporated into either all or any of the turbine rotor sections 62 or 73, or 12 in preferred embodiment. The shown nozzle is of the divergent-convergent type. The convergent section 85 is separated from the divergent section 86 by the throat 87. Fig. 7 shows part of an alternative embodiment where the discharge 101 is followed by a row of stationary vanes 102 (integrated with the housing 103, which may also host the heat exchanger 106) succeeded by a row of rotating blades 107 (integrated with the rotor member 108). The gases are prevented from discharging into the zone 110 by a sealing ring 109. After reading the above, the person skilled in the prior art will immediately realise that further obvious embodiments are possible which lie within the scope of the appended claims.

Claims

1. Reaction turbine engine (1, 21, 41) comprising a rotor member (2, 22, 42) having a structurally integrated inlet (95, 97), compressor (10, 23, 50), heating chamber (11, 31, 51) and a reaction turbine (12, 28, 62), wherein said reaction turbine is provided near the outer periphery of said rotor member (2, 22, 42) and said rotor member having a rotational axis (6, 56), characterized in that an additional compressor (3, 53) is provided, wherein the discharge of said additional compressor (3, 53) is connected to the inlet (95, 97) of the rotor member through a stationary conduit (9, 69), said additional compressor being a radial compressor having a stator part comprising a casing (14, 64) and said conduit (9, 69) and a rotor part (13, 63), said rotor part being fixedly and coaxially connected to said rotor member (2, 22, 42) wherein the inlet of said additional compressor (3, 53) is provided near said rotational axis (6, 56).

2. Reaction turbine engine according to claim 1, wherein said rotor member comprises a bladed compressor impeller.

3. Reaction turbine engine according to one of the preceding claims, wherein said additional compressor is provided adjacent to said rotor member and is being a separate module.

4. Reaction turbine engine according to one of the preceding claims, wherein the inlet and heating chamber are provided according to a line being substantially perpendicular to said rotational axis.

5. Reaction turbine engine according to one of the preceding claims, comprising a shaft of said rotor member, wherein the additional compressor comprises an axial rotor and a stator, and said axial rotor is being fixed on said shaft (5, 55).

6. Reaction turbine engine according to one of the preceding claims, wherein said additional compressor comprises a stationary diffuser.

7. Reaction turbine engine according to one of the proceeding claims, wherein said heating chamber is a combustion chamber.

8. Reaction turbine engine according to claim 7, wherein fuel is added through a separate conduit (18) to said combustion chamber (11).

9. Reaction turbine engine according to claim 8, wherein said conduit (18) includes the rotational axis (6) of said reaction turbine engine.

10. Reaction turbine engine according to one of the preceding claims, comprising a water injection.

11. Reaction turbine engine according to one of the preceding claims, wherein the compressor has a rotor having the diameter smaller than 7 cm.

12. Reaction turbine engine according to one of the preceding claims, comprising an electric generator (4) connected to said reaction turbine engine.

13. Reaction turbine engine according to one of the preceding claims comprising two rows of discharges being connected to said rotor member and flow controlling passages in stationary baffles positioned between said rows.

14. Reaction turbine engine according to claim 13, wherein said stationary baffles are part of a housing in which said rotor member is accommodated.

15. Reaction turbine engine according to one of the preceding claims, wherein the discharges comprise nozzles, having, in the direction of the flow, a convergent part and a divergent part.

16. Combined heat and power generation system for stationary applications, such as household, corporate and industrial, which generates either heat, power, or both, comprising a heating system and a reaction turbine engine according to one of the preceding claims.

17. Combined heat and power generation system for mobile applications on board of vehicles/craft/vessels, which generates either heat, power, or both, comprising a fuel supply, heat exchanger and gas discharge, wherein a reaction turbine engine according to one of the preceding claims is provided.