POLLUTANT FILTRATION IN A TURBOMACHINE TEST BENCH

Abstract

Test bench (1) for a turbomachine (2), comprising: - a passage (3) configured to receive a turbomachine (2) during testing and comprising a corridor (6) allowing the circulation of a gas flow (F), - an admission device (20) for at least one pollutant intended to mix with the gas flow (F), - a decontamination system (21) for capturing the admitted pollutant(s), this decontamination system comprising a pollution filter (22), characterized in that the pollution filter (22) is an electrostatic precipitator, and in that the decontamination system (21) further comprises a control circuit (23) which is connected to the electrical source (46) and to at least one pollution analyzer (24). Figure for the abstract: Figure 3

Description

Title of the invention: FILTRATION OF POLLUTANTS IN A TURBOMACHINE TEST BENCH Technical field of the invention

[0001] The present invention relates to the general field of turbomachine testing. It applies to any type of aeronautical or terrestrial turbomachine, in particular to aircraft turbomachines such as turbojets and turboprops. The invention thus relates to a turbomachine test bench comprising a device for admitting at least one pollutant and a device for filtering this pollutant. Technical background

[0002] A turbomachine, such as a turbojet, makes it possible to transform an energy potential, from fuel and oxidizer, into kinetic energy generating a force called thrust. During the design or maintenance of a turbomachine, various tests are carried out to validate its proper functioning. Indeed, even if the operating principle of a turbomachine seems simple, the pre-project, development and certification phases, as well as the post-certification, engine life and demonstration by testing phases for the purpose of continuous improvement, in particular, can last nearly a decade and present many complexities. Thus, during testing, a series of measurements are carried out to monitor key parameters. These measurements can be carried out both directly on the turbomachine or on its environment. In order to conduct such engine tests (or engine trials), on the ground or in flight, the turbomachine is installed in a specific test bench. This is adapted to recreate flight conditions while remaining on the ground. Such a test bench has a corridor forming a test chamber receiving the turbomachine. Vertical chimneys delimit the ends of the corridor to form an inlet and an outlet. The chimneys respectively receive and reject the air flow propelled by the turbomachine. Devices reduce the noise pollution inherent in the operation of the turbomachine, which is propagated by the chimneys. Partial tests can also be carried out, on a part or a set of parts, for example for materials testing. Generally speaking, the use of test benches can be long, with tests lasting years in many cases. Patent application EP-A1-3 199 206 discloses an example of such a test bench with a “U” configuration, i.e. showing an inlet chimney and a outlet chimney, the chimneys being connected by a horizontal corridor containing the turbomachine. Engine test bench installations require specific equipment to manage the supply of fuel, as well as compressed air, oil, and electricity. The same applies to partial or material test bench installations. Engine reliability, robustness and maximizing engine uptime are major issues these days, and current test bench solutions, which do not allow for endurance testing under controlled environments and the use of variable parameters, are not entirely satisfactory. In particular, material tests on certain phenomena, such as corrosion, erosion, coking, among others, are restricted by a number of variables which are fixed, such as for corrosion for example: the quantity of pollutant in the environment fixed during the test although variable; the temperature also fixed although variable within the engine; the pressure fixed as well as variable within the engine. However, corrosion depends in particular on the combination of these parameters and can have a more or less virulent impact. One of the problems nowadays is that it is difficult to make correlations between tests carried out on benches with fixed parameters while the engine sees variable parameters. In particular, it is difficult, during classic endurance tests on engines, to perceive certain phenomena (corrosion, erosion, coking, etc.) as they are actually experienced due to the test conditions with in particular clean air on the ground unlike certain air environments. In document FR-A1-3 120 942, the Applicant proposed a turbomachine test bench with an environment more representative of that experienced by the turbomachine under normal operating conditions with the aim of identifying in advance the difficulties likely to appear during normal use and not perceived during the development phase, in order to adapt the usage criteria accordingly. It thus proposed to equip a test bench with a device for admitting at least one pollutant intended to mix with the air flow passing through the turbomachine.

[0003] This improved test bench makes it possible to represent the environment seen by an engine in normal use and to prevent, through endurance tests, phenomena currently experienced and not expected until now. It also allows an improvement in engine reliability by establishing inspection criteria before damage and the elimination of technical problems by reducing the occurrence of certain phenomena, for example corrosion, erosion, coking, among others. It also makes it possible to reduce the necessary removals of engines, improve the choice of materials, reduce maintenance, and thus costs.

[0004] The test bench includes a decontamination system at its outlet to capture the pollutant(s) admitted. The decontamination system includes a pollution filter, which allows unwanted pollution to be recovered or blocked.

[0005] The present invention proposes an improvement to this technology which makes it possible to release as few particles as possible, or even none at all, into the atmosphere during a test. Summary of the invention

[0006] The present invention relates to a test bench for a turbomachine, comprising: - an inlet, - an outlet, - a passage in communication with the inlet and the outlet, the passage being configured to receive a turbomachine during testing and comprising a corridor allowing the circulation of a gas flow, - a device for admitting at least one pollutant intended to mix with the gas flow coming from the inlet,

[0007] - a decontamination system at the outlet allowing the capture of the pollutants admitted, this decontamination system comprising a pollution filter,

[0008] characterized in that the pollution filter is an electrofilter which is connected to an electrical source and which comprises:

[0009] - conductive wires which are connected to a first terminal of the electrical source in order to to ionize the admitted pollutant(s), and

[0010] - conductive walls which are located downstream of the wires and which are connected to a second terminal of the electrical source in order to attract the pollutant(s),

[0011] and in that the decontamination system further comprises a control circuit which is connected to the electrical source and to at least one pollution analyzer located in said passage, the control circuit being configured to receive information collected by said at least one pollution analyzer and to control the electrical source.

[0012] The filtration properties of the electrostatic precipitator depend in particular on its electrical power supply. It is therefore understood that controlling the electrical power supply of the electrostatic precipitator makes it possible to vary its filtration properties. Furthermore, the pollution analyzer makes it possible, for example, to monitor the nature and quantity of pollutants discharged by the turbomachine, independently of the nature and quantity of pollutants injected into the turbomachine. The filtration properties of the electrostatic precipitator can therefore be adapted to the nature and quantity of pollutants discharged, and can be regulated over time as a function of the evolution of the nature and quantity of these pollutants. pollutants. This makes it possible to limit as much as possible, or even completely eliminate, the risk of pollutant release into the atmosphere during turbomachine testing.

[0013] The test bench according to the invention may comprise one or more of the following characteristics, taken in isolation from one another, or in combination with one another: - the control circuit is configured to control the electrical source automatically based on the information collected by said at least one pollution analyzer; - the control circuit is configured to be controlled by an operator in order to control the electrical source based on the information collected by said at least one pollution analyzer; - said at least one pollution analyzer is located between the turbomachine and the decontamination system; - The test bench further comprises a collector tube for the gas flow leaving the turbomachine, said at least one pollution analyzer being located at or in this collector tube; - said at least one pollution analyzer is based on a laser nephelometer measurement principle; - said at least one pollution analyzer is capable of measuring concentrations of TSP, PM 10, PM2.5 and PMI particles; - the first terminal is a negative terminal, and the second terminal is a positive terminal; - the wires are at a distance from the walls between 1 and 40cm. - the electrostatic precipitator is configured to generate a potential difference between the wires on the one hand, and the walls on the other, between 1,000 and 150,000 volts. - said at least one pollutant comprises sulfur and / or sand; - the corridor is delimited upstream by a horizontal inlet chimney and downstream by a vertical outlet chimney, the test bench being in a so-called “L” configuration; - the corridor is delimited upstream by a vertical inlet chimney and downstream by a vertical outlet chimney, the test bench being in a so-called “U” configuration;

[0014] — the test bench outlet includes a door for evacuating retained particles by the electrostatic precipitator;

[0015] — the outlet of the test bench includes a container for collecting the retained particles by the electrostatic precipitator. Brief description of the figures

[0016] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0017] [Fig-1] [Fig.l] represents a test bench in accordance with the invention receiving a engine in test phase, in an “L” configuration; [Fig.2] [Fig.2] represents a test bench in accordance with the invention receiving an engine in the test phase, in a “U” configuration; [Fig.3] [Fig.3] is a partial schematic and perspective view of an electrostatic precipitator; and

[0018] [Fig.4] [Fig.4] is a schematic perspective view of a pollution analyzer.

[0019] Throughout these figures, identical references may designate identical or similar elements. Furthermore, the various parts shown in the figures are not necessarily shown on a uniform scale, in order to make the figures more readable. Detailed description of the invention

[0020] [Fig.l] represents in a simplified manner a test bench 1 of a turbomachine 2, for example an aircraft turbojet or turboprop. According to the configuration represented in this [Fig.l], the test bench 1 is said to be “L” shaped. The test bench 1 forms an infrastructure or construction. It comprises a passage 3, or test chamber, with an inlet 4 and an outlet 5. This passage 3 comprises an essentially elongated corridor 6. It may have a length greater than 50 meters. The length of the corridor 6 allows the straight-line circulation of an air flow or gas flow F, i.e. an air flow F passing through the passage 3. This air flow F circulates through the test bench 1 due to the blast of the turbomachine 2. In order to limit the flow resistance, in particular the entry of an air flow F into the turbomachine 2, the corridor 6 may have a passage section greater than or equal to 50 m2. The passage section, or free section, can be measured upstream of the fixing zone 8 intended to receive the turbomachine 2. The fixing zone 8 can be a section of the corridor 6 according to its length. The passage section can be observable over at least a quarter of the length of the corridor 6, preferably over the majority of the length. The fixing zone 8 is optionally provided with fixing means 9, for example a fixing arm, where the turbomachine 2 is mounted. These fixing means 9 can extend vertically from the ceiling of the corridor 6, in the manner of a column or a post. They make it possible to mount the turbomachine 2 with an offset, and to center the latter in the middle of the corridor 6. The centering is vertical and horizontal. The corridor 6 is delimited by chimneys, a horizontal chimney 10a at the inlet 4 and a vertical chimney 11 at the outlet 5. They respectively allow a horizontal air intake and a vertical exhaust in elevation relative to the corridor 6. This “L” configuration is not limiting of the invention. [Fig.2], described below, has a “U” configuration but other configurations are possible, for example without chimneys. Similarly, a single chamber can form the passage 3. At the entrance 4 there is a door 7. In addition, at the entrance to corridor 6, the test bench 1 has a grid 15 to intercept debris likely to disrupt the test and damage the turbomachine 2. Furthermore, the test bench comprises a collector tube 16 for the gas flow F produced by the test downstream of the turbomachine 2. The collector tube 16 is arranged horizontally and comprises at its outlet a diffuser 17 in the vertical outlet chimney 11. The collector tube 16 is also configured to absorb the noise produced by the test. In addition, the vertical outlet chimney 11 comprises a noise reduction device 18, in this case acoustic baffles. Although not shown, these acoustic baffles may also be present in the inlet chimney 10a, or the inlet chimney 10b on the. The test bench 1 allows endurance tests in a controlled environment. Thus, the test bench 1 comprises a device 20 for admitting at least one pollutant intended to mix with the air flow F coming from the inlet 4. This device 20 for admitting one or more pollutants is for example located at the level of the grid 15, between the inlet chimney 10a and the corridor 6. The intake device 20 makes it possible to contaminate the air with pollutant(s) so that the environment of the turbomachine 2 under test is as close as possible to real flight conditions. The intake device 20 may comprise a system for regulating said at least one introduced pollutant. The pollutant(s) may include sulfur for the purpose of testing corrosion, for example, or sand for the purpose of testing erosion, for example. Advantageously, the intake device 20 may include a cylinder comprising a controlled concentration of pollutant(s). For example, in the case of sulfur, it may be a cylinder marketed with a specific quantity of pollutants measured in particles per million (ppm), marketed by the company Air Liquide, for example. Test bench 1 also includes a decontamination system 21 at outlet 5 to capture the previously injected pollutant. This decontamination system mination 21 may include a pollution filter 22 making it possible to recover, or block, unwanted pollution. This decontamination system 21 may include at least one discharge valve for evacuating the polluted air to decontaminate the enclosure of the test bench 1. This may be done by suction or ventilation. This may also allow the filter to be changed if it is clogged. Test bench 1 allows endurance tests to be carried out on engines in a so-called "polluted" environment. In addition, the injection of the pollutant(s), for example sulfur for corrosion tests, can be carried out in a controlled manner. [Fig.2] also represents in a simplified manner a test bench 1 of a turbomachine 2, for example an aircraft turbojet or turboprop, now with a test bench 1 called "U". In comparison with the, the common references are not described again. In this “U” configuration, corridor 6 is delimited by vertical chimneys, a vertical chimney 10b at inlet 4 and a vertical chimney 11 at outlet 5. They respectively allow a vertical air intake and a vertical exhaust at an elevation relative to corridor 6. At the junction between the vertical upstream chimney 10b and the corridor 6, the test bench 1 is equipped with a series of deflection blades 12. They allow the air descending from the inlet chimney 10b to be returned in the horizontal direction. The deflection blades 12 extend horizontally, and cross the entire corridor 6. They have curved profiles.

[0021] The present invention proposes to improve the test bench 1 of [Fig. 1] or 2 by equipping it with an improved decontamination system 21. In particular, the pollution filter 22 is an electrostatic precipitator 40 which is connected to an electrical source, and the decontamination system 21 further comprises a control circuit 23 which is connected to the electrical source and to at least one pollution analyzer 24 located in the passage 6, the control circuit 23 being configured to receive information collected by the pollution analyzer(s) 22 and to control the electrical source for the purpose of supplying the electrostatic precipitator 40.

[0022] An electrostatic precipitator 40 is schematically represented in [Fig.3].

[0023] The electrostatic precipitator 40 is a filter configured to filter a gas flow and in particular to retain solid particles contained in this gas flow.

[0024] The electrostatic precipitator 40 comprises:

[0025] - conductive wires 42 which are connected to a first terminal 44 of a source electric 46, and

[0026] - conductive walls 48 which are connected to a second terminal 50 of the source electric 46.

[0027] The electrostatic precipitator 40 is mounted in the outlet 5 so that the wires 42 pass through the vertical chimney 11 in order to ionize polluting particles 70 contained in the flow F, and the walls 48 are located in the vertical chimney 11, downstream of the wires 42, in order to attract the particles thus ionized.

[0028] The wires 42 extend for example in a plane perpendicular to the direction of flow of the stream and therefore for example in a horizontal plane. The wires 42 are preferably regularly spaced from each other.

[0029] The number of threads 42 is preferably between 5 and 400, and for example between 5 and 200.

[0030] The diameter of the wires 42 is for example between 5mm and 50mm.

[0031] The wires 42 have for example a length between 200mm and 600mm.

[0032] The wires 42 are for example made of copper.

[0033] The walls 48 have, for example, a vertical orientation so as not to disturb the flow of the stream F. The walls 48 are preferably regularly spaced from one another.

[0034] The number of walls 48 is preferably between 5 and 400, and for example between 5 and 200.

[0035] The number of walls 48 can be equal to the number of wires 42.

[0036] The walls 48 can be axially aligned with the wires 42 or on the contrary be arranged in a staggered pattern relative to the wires 42.

[0037] The dimensions of the walls 48 are for example of length (axial) between 50mm and 150mm and height (radial) between 200mm and 600mm.

[0038] The walls 48 are for example made of copper.

[0039] The wires 42 are preferably at an axial distance from the walls 48 of between 1 and 40cm.

[0040] In the example shown, the wires 42 are connected to the negative terminal 44 and are therefore intended to be negatively charged. The particles 70 are ionized and become negatively charged as they pass through the wires 42. The walls 48 are connected to the positive terminal 50 and are positively charged. The walls 48 attract the particles 70 of opposite charges. These particles 70 come into contact with the walls 48 and their path inside the bench is thus stopped.

[0041] The particles 70 can then be evacuated through a door 30 into a collection tank 31.

[0042] The electrical source 46 is preferably configured to generate a high voltage direct current (preferably greater than or equal to 1000 volts), so that the electrostatic precipitator 40 generates a potential difference between the wires on the one hand, and the walls on the other hand, of between 1,000 and 150,000 volts depending on the applications.

[0043] In a particular embodiment of the invention, the air flow F is freed from more than 90 to 98% of the solid particles it contains. Typically, these particles have an average size between 10 pm and 70 pm.

[0044] The filtration properties of the electrostatic precipitator 40 depend in particular on its electrical power supply. It is therefore understood that controlling the electrical power supply of the electrostatic precipitator 40 makes it possible to vary its filtration properties.

[0045] An example of a pollution analyzer 24 is shown in [Fig. 4]. It may for example be an electronic box 25 connected to a probe 26 intended to be scanned by the flow F. The connection of the analyzer 24, or of its box 25, to the circuit may be of the wired or wireless type.

[0046] The analyzer 24 is preferably based on a nephelometer laser measurement principle.

[0047] The analyzer 24 is preferably capable of measuring concentrations of TSP particles (total suspended particles), PM 10 (particles larger than approximately 10 pm), PM2.5 (particles larger than approximately 2.5 pm), PMI (particles larger than approximately 1 pm).

[0048] The pollution analyzer 24 is preferably located between the turbomachine 2 and the decontamination system 22. It is for example located at or in the collector tube 16.

[0049] The analyzer 24 makes it possible to monitor the nature and quantity of pollutants discharged by the turbomachine 2, independently of the nature and quantity of pollutants injected into the turbomachine 2.

[0050] The filtration properties of the electrostatic precipitator 40 can therefore be adapted to the nature and quantity of pollutants discharged, and can be regulated over time depending on the evolution of the nature and quantity of these pollutants.

[0051] For this, the control circuit 23 can be configured to control the electrical source 46 supplying the electrostatic precipitator 40 automatically based on the information collected by the pollution analyzer(s) 24.

[0052] Alternatively, the control circuit 23 is configured to be controlled by an operator in order to control the electrical source 46 supplying the electrostatic precipitator 40 as a function of the information collected by the pollution analyzer(s) 24.

[0053] The invention makes it possible to reduce the external pollution that is generated during hundreds or more of engine tests that take place continuously. It also makes it possible to reduce the carbon footprint.

[0054] Furthermore, this invention has a secondary but nevertheless very interesting advantage, preferably in an isolated bench, which would be a more precise analysis of the pollution captured by collection and therefore recalibrate the predictive system of the test.

Claims

Claims

1. Test bench (1) for a turbomachine (2), comprising: - an inlet (4), - an outlet (5), - a passage (3) in communication with the inlet (4) and the outlet (5), the passage (3) being configured to receive a turbomachine (2) during testing and comprising a corridor (6) allowing the circulation of a gas flow (F), - an admission device (20) for at least one pollutant intended to mix with the gas flow (F) coming from the inlet (4), - a decontamination system (21) at the outlet (5) making it possible to capture the pollutant(s) admitted, this decontamination system comprising a pollution filter (22), characterized in that the pollution filter (22) is an electrostatic precipitator which is connected to an electrical source (46) and which comprises: - conductive wires (42) which are connected to a first terminal (44) of the electrical source (46) in order to ionize the pollutant(s) admitted, the pollutants admitted,and - conductive walls (48) which are located downstream of the wires (42) and which are connected to a second terminal (50) of the electrical source (46) in order to attract the pollutant(s), and in that the decontamination system (21) further comprises a control circuit (23) which is connected to the electrical source (46) and to at least one pollution analyzer (24) located in said passage (6), the control circuit (23) being configured to receive information collected by said at least one pollution analyzer (24) and to control the electrical source (46).,

2. Test bench (1) according to claim 1, wherein the control circuit (23) is configured to control the electrical source (46) automatically based on the information collected by said at least one pollution analyzer (24).

3. Test bench (1) according to claim 1, wherein the control circuit (23) is configured to be controlled by an operator in order to control the electrical source (46) according to the information collected by said at least one pollution analyzer (24).

4. Test bench (1) according to one of the preceding claims, wherein said at least one pollution analyzer (24) is located between the turbomachine (2) and the decontamination system (21).

5. Test bench (1) according to one of the preceding claims, in which it further comprises a collector tube (16) of the gas flow leaving the turbomachine (2), said at least one pollution analyzer (24) being located at or in this collector tube (16).

6. Test bench (1) according to one of the preceding claims, wherein said at least one pollution analyzer (24) is based on a laser nephelometer measurement principle.

7. Test bench (1) according to one of the preceding claims, wherein said at least one pollution analyzer is capable of measuring concentrations of TSP, PM10, PM2.5 and PMI particles.

8. Test bench (1) according to one of the preceding claims, wherein the first terminal (44) is a negative terminal, and the second terminal (50) is a positive terminal.

9. Test bench (1) according to one of the preceding claims, in which the wires (42) are at a distance from the walls (48) of between 1 and 40 cm.

10. Test bench (1) according to one of the preceding claims, in which the electrostatic precipitator (40) is configured to generate a potential difference between the wires (42) on the one hand, and the walls (48) on the other hand, of between 1,000 and 150,000 volts.

11. Test bench (1) according to one of the preceding claims, wherein said at least one pollutant comprises sulfur and / or sand.

12. Test bench (1) according to one of the preceding claims, characterized in that the corridor (6) is delimited upstream by a horizontal inlet chimney (10a) and downstream by a vertical outlet chimney (11), the test bench (1) being in a so-called “L” configuration.

13. Test bench (1) according to one of claims 1 to 11, characterized in that the corridor (6) is delimited upstream by a vertical inlet chimney (10b) and downstream by a vertical outlet chimney (11), the test bench (1) being in a so-called “U” configuration.

Images