Constant-volume combustion module for a turbine engine

Abstract

A combustion module of a turbine engine, in particular of an aircraft, is configured for carrying out constant-volume combustion. The module includes a plurality of combustion chambers angularly distributed in a regular manner around an axis. Each chamber has an intake port for pressurized gas and an exhaust port for combustion gases. Each intake/exhaust port is configured to be opened or closed by a corresponding common rotating intake/exhaust valve which is coaxial with the axis.

Claims

1. A combustion module of a turbine engine configured for carrying out constant-volume combustion, comprising a plurality of combustion chambers arranged around an axis, each combustion chamber having an intake port configured to receive pressurized gas and an exhaust port configured to discharge combustion gases, a corresponding rotating intake/exhaust valve which is respectively associated with each intake and exhaust port, coaxial with said axis, and each intake/exhaust port being configured to be opened or closed by said rotating intake/exhaust valve, wherein the combustion chambers are angularly distributed in a regular manner around said axis, the intake ports of which are configured to be opened or closed by a common rotating intake valve, and the exhaust ports of which are configured to be opened or closed by a common rotating exhaust valve according to a Humphrey cycle comprising a phase for the intake of fresh air and for sweeping out combustion gases, a combustion phase, and an exhaust phase, wherein each combustion chamber comprises two opposing walls which are outer and inner respectively, having at least respective outer and inner surfaces shaped into cylinder portions, said respective outer and inner walls each having one of said ports having a radial opening formed in said inner or outer wall, and wherein said module comprises an outer/inner rotating tubular valve associated with each outer/inner surface of the outer/inner wall of the combustion chamber, which has a tubular element having a diameter corresponding to said outer or inner wall and rotatably mounted coaxially in or around said corresponding outer/inner surface, said tubular element having a slot arranged substantially in an axial plane of the radial opening of said port which is configured to close or release said radial opening during the rotation of said tubular element.

2. The combustion module according to 1, wherein the rotating intake/exhaust valves are synchronised in rotation with one another.

3. The combustion module according claim 1, wherein each combustion chamber is coaxially arranged around the end (54) of an internal tubular case element comprising a duct having an annular cross section, the duct having an end which opens into the periphery of said internal tubular element, which is arranged opposite the opening of the inner wall of the chamber, the inner rotating tubular valve being radially interposed between said internal tubular case element and the inner wall of the combustion chamber.

4. The combustion module according to claim 3, wherein each combustion chamber is arranged coaxially inside an external tubular case element comprising an annular duct, the outer rotating tubular valve being arranged around the outer wall of each combustion chamber in said annular duct of the external tubular case element.

5. The combustion module according to claim 4, wherein the intake port is associated with the outer wall of each combustion chamber, the intake gases being transported through the annular duct of the external tubular case element, and wherein the exhaust port is associated with the inner wall of each combustion chamber, the intake gases being evacuated through the duct (58) of the internal tubular case element.

6. The combustion module according to claim 1, wherein the combustion chambers comprise a common closing element which has the intake/exhaust rotating valves which are interconnected for conjoint rotation.

7. A turbine engine comprising a compressor module having at least one compressor and a turbine module having at least one turbine, wherein the turbine engine comprises a combustion module according to claim 1, which is supplied by the compressor module and supplies the turbine module.

Description

(1) The invention will be better understood, and other details, features and advantages of the present invention will become clearer upon reading the following description, given by way of non-limiting example with reference to the accompanying drawings, in which:

(2) FIG. 1 is a perspective view intersected by an axial plane of a concept for producing a combustion module according to the invention;

(3) FIG. 2 is a schematic axial section of the combustion module from FIG. 1;

(4) FIG. 3 is a schematic cross section of the combustion module from FIG. 2;

(5) FIG. 4 is a perspective view of a first embodiment of a combustion module according to the invention;

(6) FIG. 5 is a schematic cross section of the combustion module from FIG. 4;

(7) FIG. 6 is a perspective view with a cut-out of a turbine engine comprising a combustion module according to a second embodiment;

(8) FIG. 7 is a schematic axial section of the turbine engine from FIG. 6;

(9) FIG. 8 is a cross-sectional view of a third embodiment of a combustion module according to the invention;

(10) FIG. 9 is an axial sectional view of the combustion module from FIG. 8 and of a casing of an associated turbine engine;

(11) FIGS. 10 to 14 are schematic views of different turbine engine architectures implementing a combustion module according to the invention.

(12) In the following description, same reference numerals denote parts which are the same or have similar functions.

(13) FIGS. 1 to 5 and FIG. 8 show a combustion module 10 produced in accordance with the invention. In a known manner, the module 10 is configured to implement constant-volume combustion taking place according to the Humphrey cycle, that is to say having a time for combustion, a time for evacuation, and a time for the intake of fresh air and sweeping out combustion gases.

(14) In a known manner, the module 10 comprises a plurality of combustion chambers 12 arranged around an axis A, of which just one has been shown in FIGS. 1 to 3 to facilitate comprehension thereof. A configuration comprising a plurality of chambers 12 has been shown in FIG. 6, which shows a turbine engine 14 comprising ten combustion chambers 12 arranged around the axis A of the turbine engine. In a manner which does not limit the invention, the axis A can for example coincide with an axis of rotation of the turbine engine.

(15) As shown in FIGS. 1 and 2, each chamber 12 comprises an intake port 16 for pressurised gas and an exhaust port 18 for combustion gases. In a turbine engine of the type which has been shown in FIGS. 6 and 7, the intake port 16 for pressurised gas is supplied by a compressor module 20 of the turbine engine 14 comprising at least one compressor 22, and the exhaust port 18 for gas supplies at least one turbine module 24 comprising at least one turbine 26.

(16) In accordance with the invention, each intake port 16 or exhaust port 18 is configured to be opened or closed by a rotating intake valve 28 or by a corresponding exhaust valve 30, which is coaxial with the axis A of the turbine engine 14.

(17) For the comprehension of the invention, the module 10 which has been shown in FIGS. 1 to 3 comprises only one combustion chamber 12. The direction of rotation of the rotating intake valve 28 has been shown by a dotted arrow in FIG. 3.

(18) However, in the preferred embodiment of the invention, the module 10 comprises at least two combustion chambers 12 which are angularly distributed in a regular manner around the axis A, the intake ports 16 of which are configured to be opened or closed by a common rotating intake valve 28, and the exhaust ports 18 of which are configured to be opened or closed by a common rotating exhaust valve 30. The intake valve 28 and the exhaust valve 30 can rotate together or can be parts which can rotate differently.

(19) FIG. 5 shows by way of example a first embodiment of a module 10 comprising a common rotating intake valve 28 which supplies the three intake ports 16 of the three combustion chambers 12 of the same module 10.

(20) Similarly, FIG. 6 shows the example of a second embodiment of the module 10 comprising a common rotating intake valve 28 which supplies the intake ports of ten combustion chambers 12 of the same module 10 and a rotating exhaust valve 30 which is supplied by the ten exhaust ports of the ten combustion chambers 12 of said module 10.

(21) This configuration is particularly advantageous because it makes it possible to supply a plurality of chambers 12 with a single intake valve 28 and to evacuate the gases therefrom with a single exhaust valve 30, and this makes it possible to considerably simplify the architecture of a turbine engine comprising a combustion module 10 of this type with respect to the designs previously known from the prior art.

(22) The combustion chambers 12 are angularly distributed in a regular manner around the axis A, and each have a direction which is preferably oriented in a substantially axial direction, so as to form a structure in the shape of a barrel. However, this configuration does not limit the invention, and the chambers could be arranged according to another orientation. For example, the chambers could also be angularly distributed in a regular manner around the axis A, but each having a direction which is preferably oriented in a substantially radial direction, so as to form a structure in the shape of a star. Thus, it will be understood that a main feature of the invention is that the chambers 12 can be arranged in a radiating manner.

(23) Preferably as well, the combustion cycles of the chambers 12 are offset by an interval which is dependent on the number of chambers 12. This allows to smooth the flow of the exhaust gases supplied to the turbine module 24 by smoothing the pulse phenomena which are inherent to the constant-volume combustion cycles. In fact, if all the chambers 12 were operating simultaneously following the same times of the Humphrey cycle, the exhaust phases would all be simultaneous, and this would result in an irregular flow of exhaust gases due to being subjected to the simultaneous pulsing of the gases coming from the chambers 12. In contrast, a combustion module 10 comprising cycles of offset chambers 12 allows to smooth said pulses. It will be noted that the intake of exhaust gas by the turbine module 24 will be as homogeneous and free from pulses as the number of chambers 12 will be high.

(24) Thus, preferably, a combustion module comprising a determined number n of chambers 12 will observe the cycles of the offset chambers thereof. For a number of n chambers, a number of chambers less than half n/2 of the number n of chambers will be operated at the same time to balance the loads on the rotating valves. In particular, two opposing chambers will be on the same cycle phase, considering for example for four chambers at a determined moment two chambers in combustion and two chambers without combustion.

(25) In the preferred embodiment of the invention, the rotating intake 28 and exhaust 30 valves are synchronised in rotation with one another, rotating at the same rotational speed.

(26) This synchronisation can be achieved by any means known from the prior art, in particular in a mechanical manner.

(27) It should be noted that it is possible to provide an adjustable dephasing device between the rotating intake 28 and exhaust 30 valves in order for example to be able to modify the dephasing of the rotating intake 28 and exhaust 30 valves according to the conditions of use of the combustion module 12, the rotating intake 28 and exhaust 30 valves, once a speed has been established, remaining synchronised in rotation with one another.

(28) A preferred embodiment of the chambers 12 and the valves 28, 30 will now be described.

(29) In a preferred embodiment of the invention, each combustion chamber 12 comprises at least one wall 32, 34 having a surface 33, 35 in the form of a cylinder portion which is coaxial with the axis A.

(30) In the first and second embodiments of the invention described previously, the chambers 12 comprise a first longitudinal wall 32 having a surface 33 in the form of a cylinder portion, rotated towards the axis A, that is to say an inner wall 32, which has the two intake 16 and exhaust 18 ports, and additionally a second longitudinal wall 34, rotated away from the axis A, that is to say an outer wall 34, which has no intake or exhaust ports.

(31) In a third embodiment shown in FIGS. 8 and 9, each combustion chamber 12 comprises, extending longitudinally, a first outer wall 32, which is coaxial with the axis A and comprises at least one surface 33 in the form of a cylinder portion which is rotated away from said axis A, that is to say rotated outwardly, and which has the intake port 16, and a second inner wall 34, extending longitudinally, and having at least one surface 35 in the form of a cylinder portion, which is coaxial with the axis A and rotated towards the axis A, that is to say rotated inwardly, and which has the exhaust port 18.

(32) It will be understood that other configurations are possible without changing the nature of the invention, for example a configuration according to which the intake 16 and exhaust 18 ports would be arranged on a wall which is coaxial with the axis A and rotated away from said axis A, or a substantially reversed configuration of the third embodiment.

(33) Each port 16, 18 comprises, according to the chosen configuration, a radial opening 36, 38 which is formed in the corresponding longitudinal wall 32, 34 of the combustion chamber, the surface 33 and/or cylinder portion 35 of which is coaxial with the axis A. Each rotating intake 28/exhaust 30 valve comprises a corresponding tubular element 40, 42, having a diameter corresponding to said cylinder portion, which is rotatably mounted coaxially in the cylinder portion or around the cylinder portion of the surface 33 and/or 35 of the respective wall 32, 34. Said tubular element 40, 42 comprises a bore defining a duct 44, 46 for intake/exhaust gas which extends axially at a right angle to the combustion chamber 12, and it comprises at least one radial hole 50, 52 opening respectively into the duct 44, 46 and arranged substantially in an axial plane of the radial opening 36, 38 of said port 16, 18, which is capable of allowing the release or the closure of said radial opening 36, 38 during the rotation of said tubular element 40, 42 depending on whether or not the radial hole 50, 52 set into rotation with the tubular element 40, 42 passes in front of the radial opening 36, 38 of said port 16, 18.

(34) Thus, in the conceptual view and the first and second embodiments shown in FIGS. 1 to 7, the surface 33 in the form of a cylinder portion of the wall 32 of the combustion chamber 12 is rotated towards the axis A, and the tubular element 40, 42 of each valve 28, 30 is mounted so as to rotate inside said surface 33. Each tubular element 40 or 42 comprises an internal bore 44, 46 defining the intake/exhaust gas duct which is thus formed in the tubular element 40, 42, and which makes it possible to transport the intake gases and evacuate the exhaust gases in the direction of the flow of said gases, as shown by the arrow in FIG. 1.

(35) In the specific case of the second embodiment shown in FIGS. 6 and 7, each tubular element 40, 42 is annular and defines a corresponding internal bore 44, 46. The bore 44 in the tubular element 40 is designed to surround a duct for transporting the gases 64 coming from the compressor 22, and in the same manner the bore 46 in the tubular element 42 surrounds a duct for evacuating the gases 58 from the turbine 26. In particular, the duct for transporting the gases can be delimited close to the combustion chamber 12 by an annular intake guide 65, and the duct for evacuating the gases can be delimited close to the combustion chamber 12 by an annular exhaust guide 59.

(36) In the third embodiment shown in FIGS. 8 and 9, each combustion chamber 12 comprises two opposing walls which are outer 32 and inner 34 respectively, which comprise at least respective outer 33 and inner 35 surfaces in the shape of cylinder portions. The walls 32, 34 each comprise a port 16, 18 having a radial opening 36, 38 formed in said outer wall 32 or inner 34 wall. The combustion module 10 comprises an outer rotating tubular valve 28 and an inner rotating tubular valve 30, associated with each outer 32 and outer 34 wall of the combustion chamber 12, which each comprise a respective tubular element 40, 42 having a diameter corresponding to said outer or inner wall and which is rotatably mounted coaxially with the corresponding outer 33 or inner 35 surface in the form of a cylinder portion. Each tubular element 40, 42 comprises at least one hole 50, 52 arranged substantially in an axial plane of the radial opening 36, 38 of the port 16, 18 which is capable of closing or releasing said radial opening 36, 38 during the rotation of said tubular element 40, 42.

(37) Thus, the main difference between, firstly, the first and second embodiments of the invention, and secondly the third embodiment, is that in the first and second embodiments of the invention, the tubular elements 40, 42 forming the valves 28, 30 cooperate with the same wall 32, the axially offset ports 16, 18 of which they release or close, whereas in the third embodiment of the invention, the tubular elements 40, 42 cooperate with two radially offset walls 32, 34, the ports 16, 18 of which they release or close, said ports 16, 18 being at least offset radially.

(38) It should be noted that in the third embodiment, the ports 16, 18 can also be axially offset without this having a limiting effect on the invention.

(39) As shown in FIG. 9, in the third embodiment of the invention, each combustion chamber 12 is arranged coaxially around the end 54 of an inner tubular case element 56 comprising a duct 58 having an annular cross section. The duct 58 comprises an end 60 which opens into the periphery of said internal tubular element 56 which is arranged opposite the opening 38 of the inner wall 34 of the chamber 12, and the internal rotating valve 30 is radially interposed between said internal tubular case element 56 and the inner wall 34 of the combustion chamber 12.

(40) Similarly, the combustion chamber 12 is arranged coaxially inside an external tubular case element 62 comprising an annular duct 64, and the external rotating valve 28 is arranged around the outer wall 32 of the combustion chambers 12 inside said annular duct 64 of the external tubular case element 62.

(41) Preferably, in this third embodiment, the intake port 16 is associated with the outer wall 32 of each combustion chamber 12, the intake gases being transported through the annular duct 64 of the external tubular case element 62, and in a corresponding manner, the exhaust port 30 is associated with the inner wall 34 of the combustion chambers 12, the intake gases being evacuated through the duct 58 of the internal tubular case element 56.

(42) It will be understood that this configuration is not intended to limit the invention and could be reversed. Furthermore, for example, the intake and the exhaust could be axially offset, subject to a greater length of the combustion chamber.

(43) One particularly advantageous feature of the invention is that the combustion module 10 can comprise a common closing element 66 which has the rotating intake 28 and exhaust 30 valves and which is powered, for example, by a single drive means, the valves thus being interconnected for conjoint rotation. This configuration makes it possible to achieve, in a very simple manner, the synchronisation of the intake 28 and exhaust 30 valves. However, this configuration does not limit the invention, and the rotating intake 28 and exhaust 30 valves can be powered by different but synchronised drive means.

(44) For example, in the particular case of the second embodiment shown in FIGS. 6 and 7, the closing element 66 is shaped in the form of a wheel comprising a plate 67 in the form of a disc to which the two tubular elements 40, 42 are joined on either side.

(45) Said closing element 66 can be driven in various ways. For example, the closing element 66 can be driven by a motor 68 and a coupling by an angular gear unit 70, as shown in FIG. 1, but more simply, the closing element 66 can be coupled to a system of shafts of the turbine engine associated by means of a suitable reduction.

(46) In a variant, the intake 28 and exhaust 30 valves can of course be driven by separate drive means, which are for example synchronised.

(47) The invention can thus of course be applied to a turbine engine used in aeronautic propulsion, comprising a compressor module 20 having at least one compressor 22 and a turbine module 24 having at least one turbine 26. A turbine engine of this type comprises a combustion module 10 of the type described previously, supplied by the compressor module 20 and supplying the turbine module 24.

(48) One example of a turbine engine 14 of this type, as shown in FIGS. 6 and 7, comprises for example, as has been seen previously, a compressor module 20 having at least one compressor 22, a combustion module 10 of the type described previously, and a turbine module 24 having at least one turbine 26. In this configuration, the module 22 is connected to the turbine module 24 by a system of shafts 72.

(49) In this configuration, as shown in FIGS. 6 and 7, the compressor module 22 supplies the combustion module 10 with intake gas for example by means of a single intake duct, which combustion module 10 supplies the turbine module 24 with exhaust gas by means for example of a single exhaust duct 58, and at least one shaft of the system of shafts 22 forms the means for driving the common closing element 66.

(50) In a variant, in another embodiment which is particularly advantageous because it would give great opportunity to optimise control of the combustion, said turbine engine could comprise a combustion module having an intake valve and an exhaust valve 10 which could be dephased in an active manner according to the different operating phases of the turbine engine. Thus, the valves could be powered by a common drive means and engaged with one another, or disengaged or dephased in a selective manner, but they can also be driven independently of one another whilst being selectively synchronised, desynchronised or dephased with/from one another.

(51) The invention thus makes it possible to achieve, in a simple and reliable manner, the intake and the evacuation of the chambers 12 of a combustion module 10 of the constant-volume type.

(52) FIGS. 10 to 14 show different possible applications to different types of propulsion systems.

(53) FIG. 10 shows a first type of system in which a turbine engine 14 drives a load 74, such as a turboprop engine propeller, directly or via a reducer. In this case, the turbine module 24 is directly coupled to the load 74.

(54) FIG. 11 shows a second type of system in which a turbine engine 14 drives a free turbine 76, which in turn directly drives a load 74, such as a turboprop engine propeller. In this case, the exhaust gases of the turbine module 24 drive the free turbine 76.

(55) FIG. 12 shows a third type of system in which a combustion module 10 drives a turbine module 24, which in turn directly drives a load 74, such as a turboprop engine propeller. In this case, it is the exhaust gases of the combustion module 10 which drive the turbine module 24.

(56) FIG. 13 shows a fourth type of system in which a turbine engine 14 of the type previously described ejects gases into an exhaust nozzle 78. In this case, the propulsion is ensured by reaction.

(57) Lastly, FIG. 14 shows a fifth type of system in which a combustion module 10 directly ejects gases into an exhaust nozzle 78. In this case, the system is reduced to the simplest expression thereof and is very close in operation to a ramjet engine, with the difference that it has a higher number of combustion chambers 12 which are synchronised in the operating cycles thereof. The operating pressure is thus higher. The propulsion is also ensured by reaction.

(58) The invention thus proposes a new type of propulsion system which is particularly advantageous in that, at equal thrust, it is estimated that such a system can facilitate a gain in consumption of from 10% to 20% in relation to a conventional turbine engine.