FR3013389A1 - SYSTEM FOR MONITORING THE OPENING OF A BYPASSING SYSTEM FOR THE FLUID SUPPLY OF A TURBOMACHINE - Google Patents

Abstract

The invention relates to a system (20) for controlling the opening of a bypass system (12) for a turbomachine supply system (2). The control system (20) is configured to determine a quantity of contaminant retained by a filter (10) of the supply system (2), from the flow rate of fluid passing through the filter (10), the temperature of the fluid and a determination of the pressure difference across the filter (10). The control system (20) is further configured to detect whether the amount of contaminant determined exceeds a threshold value.

Description

TECHNICAL FIELD The invention relates to the technical field of turbomachine feed fluid supply systems. More specifically, the invention relates to a system for controlling the opening of a bypass system for supplying fluid to a turbomachine. STATE OF THE PRIOR ART In order to ensure the proper functioning of the turbomachine, the fuel supply system of the turbomachine supplies the combustion chamber with fuel with a controlled flow and pressure. For the same reason, the amount of fuel contaminant injected into the combustion chamber must remain limited. The turbomachine feed system includes a fuel filter configured to reduce the amount of contaminant from the fuel flowing to the combustion chamber. However, the filter may be clogged by the contaminant it retains. The clogging of the filter results in a decrease in the maximum flow rate of fuel that can pass through the filter and in a difference in fuel pressure across the filter. To ensure the supply of fuel to the turbomachine before the filter is replaced, the supply system of the turbomachine comprises a filter bypass system. In known manner, the bypass system is configured to open by allowing the fuel to flow towards the combustion chamber when the difference in fuel pressure across the filter becomes large enough.

In addition, the regulations in force oblige to prevent the risk of opening of the diversion system. In this context, the warning linked to the opening of the bypass system must precede the opening of the bypass system by at least some time. However, the operational constraints encourage delaying the filter change as much as possible and increasing maintenance intervals. There is therefore a need to improve the indication of the deterioration of the characteristics of the filter in accordance with the regulations in force, in particular the regulation relating to a warning preceding the opening of the filter bypass system, while limiting the mass and the the size of the turbomachine. DISCLOSURE OF THE INVENTION The invention aims to at least partially solve the problems encountered in the solutions of the prior art. In this regard, the subject of the invention is a system for controlling the opening of a bypass system for a turbomachine supply system with supply fluid, the bypass system being configured to open when a Power supply fluid filter of the power system is clogged.

The control system according to the invention is configured to determine a quantity of contaminant retained by the filter, from the flow rate of fluid passing through the filter, the temperature of the fluid and a determination of the pressure difference at the terminals. of the filter, the control system being configured to detect whether the amount of contaminant determined exceeds a threshold value.

Taking into consideration the fluid temperature, the flow rate of fluid passing through the filter and the pressure difference across the filter makes it possible to anticipate with greater precision the opening of the bypass system. Thanks to the invention, the filter is therefore likely to be changed later before the opening of the bypass system. The maintenance operations of the filter can therefore be further spaced over time. The control system determines characteristics of the fuel at the filter terminals to deduce the amount of contaminant, since the amount of contaminant is a variable whose value is more difficult to measure directly or indirectly than other parameters taken into account. that is, the temperature, the flow rate, and the pressure difference. The values of fluid temperature, fluid flow rate and pressure difference across the filter can be determined directly. In some cases, for example in the event of sensor failures or sensor failures, the temperature, flow rate and pressure difference values are likely to be estimated values or even default values. The indication of the next opening of the bypass system by a control system according to the invention is likely to be based mainly on a new programming logic of a pre-existing control system. As a result, the mass and size of the turbomachine are limited by incorporating a control system according to the invention into a turbomachine. The invention may optionally include one or more of the following characteristics combined with each other or not: The feed fluid is preferably a feed liquid. The supply liquid is for example oil or fuel. Preferably, the feed liquid is fuel. According to a particular embodiment, the control system comprises: a memory configured to store correlation data between a plurality of pressure difference values across the filter, the amount of contaminant retained by the filter, the flow rate and the temperature; fluid, a contaminant quantity determining device, configured to determine the amount of contaminant retained by the filter from the data stored in the memory as a function of flow rate, temperature and pressure difference across the filter, a device critical contaminant quantity detection system, configured to compare the determined amount of contaminant with the threshold value and detect whether the amount of contaminant exceeds the threshold value.

The correlation data stored by the memory are for example data of one or more characteristic curves of the operation of the filter. The amount of contaminant retained by the filter is particularly likely to be extrapolated from the data of the memory if it can not be calculated directly from the stored data. The extrapolation of stored data is performed for example by regression methods. According to an additional characteristic, the control system comprises a means for determining the temperature of the fluid passing through the filter. Preferably, the control system comprises means for determining the pressure difference across the filter. The temperature determining means and / or the pressure difference determining means may be dedicated additional sensors. Alternatively, the control system uses the measurements made by the pre-existing pressure and temperature sensors.

According to another embodiment, the control system comprises an alert device configured to trigger when the amount of contaminant determined exceeds the threshold value. The alert device includes a device capable of emitting a signal capable of drawing the attention of a user to the fact that the state of the filter should be inspected or the filter changed. The invention also relates to a feed fluid supply system for a turbomachine, comprising a feed fluid filter, a filter bypass system and a control system as defined above. The invention further relates to a turbomachine comprising a feed system as defined above. The invention finally relates to a method for controlling the opening of a bypass system for a turbomachine fluid supply system, the supply system comprising a feed fluid filter, the method being implemented by a control system as defined above, the method comprising: a step of determining the amount of contaminant retained by the filter as a function of the fluid temperature, the fluid flow rate and a pressure difference determination at the terminals of the filter, - a detection step if the amount of contaminant determined exceeds a threshold value, in particular a fixed or scalable threshold value. The amount of contaminant is determined in particular by the control system as a function of data correlating values of temperature, flow rate and pressure difference. Advantageously, the threshold value is determined before and / or during each flight as a function of the fluid temperature and / or the fluid flow rate. The threshold then varies in particular according to the estimated conditions for the next flight or for the rest of the flight of the turbomachine. The threshold is therefore more precise. Therefore, the anticipation of the opening of the bypass system may be more accurate.

According to an additional characteristic, the temperature of the fluid is extrapolated from the temperature of the fluid at the beginning of the flight, and estimated heat loss losses. According to another additional characteristic, the flow rate of fluid taken into account to determine the threshold value and / or at least a quantity of contaminant retained by the filter corresponds to the maximum flow circulating in the turbomachine feed system in cruising mode. The maximum flow circulating in the power system during takeoff or during the altitude rise of the aircraft is certainly higher than the flow circulating in the cruising power system.

However, current regulations require that users be warned well in advance of the upcoming opening of the diversion system. More specifically, the indication related to the opening of the diversion system during a take-off or climb-up phase should have been given during the previous flight. It follows that the maximum flow rate in the feed system at the time of the indication of an anticipation of the opening of the bypass system corresponds in practice almost always to the maximum flow circulating in the turbomachine feed system in regime cruising. The maximum flow circulating in the turbomachine supply system in cruising mode is therefore taken into account to estimate the threshold value and / or to the first approximation the amount of contaminant retained by the filter. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood on reading the description of exemplary embodiments, given purely by way of indication and in no way limiting, with reference to the appended drawings in which: FIG. 1 is a partial schematic representation of a feeding system illustrating an embodiment of the invention; Figures 2 and 3 are graphs schematically illustrating the operation of the filter shown in Figure 1; FIG. 4 illustrates the implementation of a method for controlling the opening of a fuel filter bypass system by the control system represented in FIG. 1. DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS Identical Parts , similar or equivalent of the different figures bear the same numerical references so as to facilitate the passage from one figure to another. FIG. 1 represents a supply system 2 for a turbomachine 1. The supply system 2 comprises a supply fluid filter 10, a bypass system 12 of the filter 10 and a system 20 for controlling the opening of the system bypass 12.

The feed fluid is preferably fuel feeding a combustion chamber 4 of the turbomachine 1. The fuel comes from one or more tanks 3 of the feed system 2. The feed system 2 further comprises one or more pumps 6 so that the fuel can feed the combustion chamber 4, under pressure despite the presence of hydraulic pressure losses symbolically represented under the references 7 and 9. The fuel filter 10 is configured to reduce the quantity of contaminant Qdc fuel flowing towards the combustion chamber 4 of the turbomachine 1. The contaminant present in the fuel is then retained by the filter 10 which may become clogged gradually. As a result, the feed system 2 includes a shunt system 12 configured to open when the filter 10 is clogged. The bypass system 12 is in particular a non-return valve configured to open when the difference in fuel pressure across the filter 10 exceeds a predetermined pressure value So. The control system 20 of the opening of the bypass system 12 is configured to determine a quantity of contaminant Qdc retained by the filter 10, from fluid flow data Dtf through the filter 10, temperature of the fluid Ttf and a determination of the pressure difference dPt across the filter 10. For this reason, the control system 20 includes a memory 242 and a contaminant amount determining device 24. The memory 242 is configured to store correlation data. between a plurality of pressure difference values dPt across the filter 10, amount of contaminant Qdc retained by the filter 10, flow rate Dtf and temperature of the fluid Ttf. The contaminant quantity determination device 24 is configured to determine the amount of contaminant Qdc retained by the filter 10 from the data stored in the memory 242 as a function of the flow rate Dtf, the temperature Ttf and the pressure difference dPt across the terminals. filter 10.

The operation of the control system 20 will be described in more detail with reference to FIGS. 2 to 4 and more particularly with reference to FIG. 4. The control system further comprises a means for determining the temperature of the fluid Ttf passing through the filter. 10.

The means for determining the temperature of the fluid Ttf is preferably a pre-existing temperature sensor, in particular a temperature sensor of the fuel in the reservoir or reservoirs 3. The temperature of the fuel Ttf passing through the filter 10 is then determined from This measure. Similarly, the control system 20 comprises a pressure difference determining means 22 at the terminals of the filter 10. The pressure difference determining means 22 comprises in particular one or more pressure sensors. The pressure difference dPt across the filter 10 is for example determined by comparing a measurement downstream of the filter 10 and a measurement upstream of the filter 10.

Similarly, the control system may include a fuel flow determination means in the vicinity of the filter 10, such as a flow meter 8. The control system 20 also has the function of detecting if the amount of determined contaminant Qdc exceeds a threshold value Rs. The control system 20 includes a contaminant critical quantity detection device 244 configured to compare the determined contaminant quantity Qdc with the threshold value Rs. The critical contaminant quantity detection device 244 is configured to detect then if the amount of contaminant Qdc exceeds the threshold value Rs. The critical quantity detection device contaminant 244 and the memory 242 are integrated in practice in a motor ECU 24 of the turbine engine 1 or an aircraft incorporating the turbomachine 1. The contaminant quantity determination device 24 comprises in practice the engine control computer 24 progra mmed with software for determining the amount of Qdc contaminant. The engine computer 24 also includes a software for comparing a quantity of contaminant at the threshold value R, and for detecting the exceeding of the threshold value R 1. In order to draw the attention of a user to the risk of the next opening of the bypass system 12, the control system 20 includes an alerting device 26 configured to trigger an alarm when the determined amount of contaminant Qdc exceeds the threshold value R ,. The warning device 26 is notably a device for processing and displaying the signal at the output of the critical quantity of contaminant device 244. The signal emitted by the warning device 26 is a light and / or sound signal, suitable for draw a user's attention to the fact that the filter 10 should be changed soon or at least that an inspection operation of the state of the filter 10 should take place shortly. The various characteristic curves of the operation of the filter 10 of FIG. 2 are referenced a) to h). They represent the evolution of the pressure difference dPt at the terminals of the filter 10 as a function of the amount of contaminant Qdc retained by the filter 10, for different given values of fuel flow Dtf and different given fuel temperature values Ttf in the vicinity. The curves a, b, c, d are made at low temperature with decreasing flow rates of the curves a to d. The curves e, f, g, h are made at high temperature with decreasing flow rate values of the curves e to h. The indication of the opening of the bypass system 12 precedes for at least a certain duration the opening of the bypass system 12. This duration is fixed by the regulations in force according to the turbomachine 1. It currently coincides with a duration value equal to half the maximum duration of a turbine engine 1 flight under extreme conditions of contaminant deposition rate in the filter 10. Therefore, the threshold value R is significantly lower than the corresponding amount of contaminant at the predetermined pressure value So. FIG. 2 shows that the next indication of the opening of the bypass system 12 only on the basis of a fixed threshold of pressure difference across the filter 10 is less accurate than the indication of the upcoming opening of the opening of the bypass system 12 based on the determination of the amount of contaminant Qdc. It emerges in particular from the analysis of curves a) to h) that at the differential pressure dPt across the fixed filter 10, the amount of contaminant Qdc determined across the filter 10 decreases with an increase in the fluid flow Dtf. Moreover, at the difference of pressure dPt across the fixed filter 10, the amount of contaminant Qdc determined across the filter 10 increases with an increase in the temperature of the fluid Ttf. FIG. 3 is a representation similar to that of FIG. 2. It illustrates that it is possible to significantly further improve the accuracy of the indication of the opening of the bypass system 12 with an evolutionary threshold value R . The curves i) and j) are distinguished by the temperature of the fluid passing through the filter 10 for a fuel flow rate equal to the flow rate cruising. The curves i) and j) are also differentiated by the different threshold values R 1 and R 5, which derive from the temperature difference of the fluid passing through the filter 10. The method of controlling the opening of the bypass system 12 is now The control method mainly comprises a step 64 of determining the amount of contaminant Qdc retained by the filter 10 and a detection step 66 if the amount of determined contaminant Qdc exceeds the threshold value R 1. The amount of contaminant Qdc is determined in step 64 from the stored data and measurements, estimates or approximations made in relation to the temperature of the fluid Ttf, the fluid flow rate Dtf and the pressure difference dPt at filter terminals 10.

Preferably, the temperature of the fluid Ttf, the fluid flow rate Dtf and the pressure difference dPt across the filters 10 taken into account for the step 64 are measured in real time or at least regularly. The method continues with the detection step 66 if the quantity of determined contaminant Qdc exceeds the threshold value R 'also called step 66 of critical quantity detection of contaminant, according to the branch 642.

During step 66, the quantity of contaminant Qdc just determined is compared with the threshold value R 1. The engine computer 24 then detects whether the amount of contaminant Qdc is greater than the threshold value R 1. If this is the case, the control method continues according to the branch 662 by the emission of a signal in this direction by the warning device 26 during a step 68 signaling the exceeding of the threshold value R ,. Otherwise, the process continues according to branch 664. The step 64 of determining the quantity of contaminant Qdc is repeated thereafter until the control system detects that the amount of contaminant Qdc exceeds the threshold value R, or until the control system 20 stops. The control method is initiated, optionally optionally, by a step 62 for establishing the threshold value R 1. When the threshold value R is a fixed value, the threshold value R is for example equal to a threshold value. In this case, step 62 is possibly not repeated during a subsequent implementation of the control method. In a variant, the threshold value R 1 is an evolutionary value. In this preferred configuration, the threshold value R may also include a default value, such as a threshold value. The threshold value R can also be determined before and / or during each flight, in particular as a function of the fluid temperature Ttf and / or the fluid flow rate Dtf. If necessary, the threshold value R, is modified several times during the same flight. Finally, the threshold value R can also be modified after a turbine engine flight 1. Whether the threshold value R, whether scalable or not, the fluid flow Dtf taken into account to determine the threshold value R, preferably corresponds to the maximum flow rate. Dniax circulating in the feed system 2 of turbomachine 1 in cruising mode. Indeed, the maximum flow Dniax in the feed system 2 at the time of the indication of an anticipation of the opening of the bypass system 12 is in practice equal to the maximum flow circulating in the turbomachine supply system in cruise regime.

The temperature of the fluid Ttf taken into account for the determination of the threshold value R, is for example extrapolated from the temperature of the fluid at the beginning of the flight Tof of the turbine engine 1, and heat loss losses estimated in the course of next flight or during the remainder of the flight.

Once the threshold value R, has been established during the step 62 of establishing the threshold value R ', the control method continues with the step 64 according to the branch 622. On the contrary, the measurements of fluid temperature Ttf, fluid flow rate Dtf and pressure difference dPt at the terminals of the filter 10 during step 64 may lead to re-evaluation of the threshold value during a flight. In this case, the process continues according to the arrow 644 and the step 62 of establishing the threshold value R, is repeated. Of course, various modifications may be made by those skilled in the art to the invention which has just been described without departing from the scope of the disclosure of the invention.

Claims (10)

REVENDICATIONS1. Control system (20) for opening a bypass system (12) for a turbomachine supply system (2) with supply fluid, the bypass system (12) being configured to open when a feed fluid filter (10) of the feed system (2) is clogged, characterized in that the control system (20) is configured to determine a quantity of contaminant (Qdc) retained by the filter (10), from the flow rate of fluid (Dtf) passing through the filter (10), the temperature of the fluid (Ttf) and a determination of the pressure difference (dPt) across the filter (10) , and in that the control system (20) is configured to detect whether the determined amount of contaminant (Qdc) exceeds a threshold value (R5). 2. Control system (20) of the opening according to the preceding claim, characterized in that it comprises: a memory (242) configured to store correlation data between a plurality of pressure difference values (dPt) to filter terminals (10), contaminant quantity (Qdc) retained by the filter (10), flow rate (Dtf) and fluid temperature (Ttf), - a contaminant quantity determination device (24) configured to determine the amount of contaminant (Qdc) retained by the filter (10) from the data stored in the memory (242) as a function of flow rate (Dtf), temperature (Ttf) and pressure difference (dPt) at the terminals of the filter (10), a critical contaminant quantity detecting device (244), configured to compare the determined contaminant quantity (Qdc) with the threshold value (R,) and detect whether the amount of contaminant (Qdc) exceeds the threshold value (R5). 3. Control system (20) according to any one of the preceding claims, characterized in that it comprises means for determining (5) the fluid temperature (Ttf) passing through the filter (10), and preferably a means for determining the pressure difference (22) across the filter (10). 4. Control system (20) according to any one of the preceding claims, characterized in that it comprises an alert device (26) configured to trigger when the determined amount of contaminant (Qdc) exceeds the threshold value ( R5). Method for controlling the opening of a branching system for a turbomachine fluid supply system (2) (2), the supply system (2) comprising a supply fluid filter (10) characterized in that the method is carried out by a control system (20) according to any one of claims 1 to 4, the method comprising: a step of determining the amount of contaminant (Qdc) retained by the filter (10) depending on the fluid temperature, the fluid flow rate (Dtf) and a pressure difference determination (dPt) across the filter (10), a detection step if the determined amount of contaminant (Qdc) ) exceeds a threshold value (R,), especially a threshold value (R,) fixed or evolutive. 6. Control method according to the preceding claim, characterized in that the threshold value (R) is determined before and / or during each flight as a function of the fluid temperature (Ttf) and / or the fluid flow rate (Dtf). . 7. Control method according to any one of claims 5 to 6, characterized in that the fluid temperature (Ttf) is extrapolated from the fluid temperature at the beginning of the flight (Tof) of the turbomachine (1), and estimated heat loss losses. 8. Control method according to any one of claims 5 to 7, characterized in that the fluid flow (Dtf) taken into account to determine the valueseuil (R) and / or at least a quantity of contaminant (Cbc) retained by the filter (10) corresponds to the maximum flow rate (Dniax) flowing in the feed system (2) of the turbomachine (1) in cruising mode. Supply system (2) for turbomachine feed fluid (1), comprising a feed fluid filter (10), a bypass system (12) of the filter (10) and a control system ( 20) according to any one of claims 1 to 4. 10. Turbomachine (1) comprising a power system (2) according to the preceding claim.