RU2669913C1 - Aircraft fuel system - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: invention relates to fuel systems of aircraft. Fuel system consists of a tank, an inertial valve, a supply compartment with a partition, pipelines for fuel sampling from the tank. Inertial valve is cylindrical load (6) located along the axis in the direction of flight and moving axially along balls (7) located in separator (8) mounted on inner cage (9) pressed onto load (6). Load (6) contains on the ends of seal (10, 11), interacting with seats (12), oppositely arranged on flanges (14, 15) of valve body (16). Flanges (14, 15) are interconnected with an abutment along outer cage (17) of load (6) along balls (7), outer cuff (17) at each end comprises openings (18) communicating intake conduits (4, 5) fuel from the tank with the consumption compartment.

EFFECT: invention provides a continuous supply of the engine with fuel in any position of the aircraft.

1 cl, 4 dwg

Description

The invention relates to devices of aircraft (LA) and can find application in the design of the fuel system of the engine of an unmanned aircraft in the circuit of fuel intake devices at any positions of the aircraft, including negative overloads.

Due to the fact that the formation of air jams is unacceptable in the system, the design of the tank as a mandatory component includes drainage and pressurization systems of the fuel tank, as well as a consumable tank for continuous supply of fuel to the engine in all modes. In addition, complex automation systems, partitions, and fixtures are used to distribute fuel generation and control this process, providing for increased operating requirements.

Known power plants LA [1. Polikovsky V.I. Aircraft power plants / V.I. Polikovsky. - M .: Oborongiz, 1952. - S. 54-60, Fig. 28-32; from. 71-72, FIG. 42, 44; from. 157-160, FIG. 108-111.] With engine fuel supply systems from a tank containing a consumable compartment, partitions, swing valves, floats or inertia loads, air separators, as well as drainage systems into the atmosphere or boost cavity; ejectors are also used in aircraft systems [1. S. 133-134, FIG. 90]. The listed devices should be used in a simplified version, taking into account the specific purpose of the aircraft.

Known simplified diagram of the fuel system [2. Polikovsky V.I. Power plants of aircraft with jet engines / V.I. Polikovsky, D.N. Surnov. - M.: Mechanical Engineering, 1965. - p. 20-22; 30-55, fig. 10, 38, 40], where in fig. 10, a fuel tank with a fuel extrusion bag was introduced into the fuel system, which ensures uninterrupted operation of the engine in any modes, but depending on the layout of the aircraft, it is often not possible to use the indicated device. In fig. 38 [2.] shows a diagram with a long tank, divided into three compartments, where the fuel is produced sequentially by overflow through the compartment located in the center of mass of the tank. This scheme is used for relatively small tanks with an increased boost pressure, which also cannot be optimally applied for different aircraft systems and layouts. In fig. 40 [2.] shows the operation patterns of inertial valves, the operation and reliability of which significantly depends on the overload perceived by the aircraft.

Known fuel system unmanned aircraft [3. Pat. RU 2523729 C1, IPC B64C 29/00. Fuel system of an unmanned aerial vehicle / Kostkin M.D., Popovich A.M. Publ. 07/20/2014. Bull. No. 20], where the problem of centering the aircraft and fuel consumption was solved, but to ensure reliable operation of the fuel system at any aircraft position, including during negative overloads, it lacks special devices that exclude gas from entering the fuel.

It is known the use of ejectors in devices [4. Hydraulic systems of high pressure / Ed. Yu.N. Laptev. - M.: Mechanical Engineering, 1973. - S. 117-119 Fig. 58, 59], or [5. Pat. RU 2016266 C1, IPC F04F 5/54. Pump-ejector installation / Gorodivsky A.V., Roshak I.I., Gorodivsky L.V. - Publ. July 15, 1994], or [6. Pat. RU 2366840 C1, IPC F04F 5/30. Ejector / Panchenko V.I., Panchenko O.V., Raskin A.I., Rukavishnikov A.I., Sychenkov V.A., Sharapov L.E. Publ. 09/10/2008. Bull. No. 25], in the proposed fuel system, the ejector is used as an air separator and a device for draining the consumable compartment.

Devices [1-6] are considered as analogues of the present invention, but they do not fundamentally solve the problem of degassing the fuel entering the engine, which does not exclude cavitation processes in the fuel supply system. Air separation devices do not provide reliable gas removal from the fuel. The ejector systems in these devices cannot be used in the indicated design for the degassing of fuel in the aircraft fuel system.

The closest in technical essence and the achieved result are the design of the fuel tanks and intake devices in the fuel tanks [1. from. 56-58, FIG. 28, 29.], containing a consumable compartment with a baffle and an inertial valve, providing continuous fuel supply to the engine in all modes. But these devices do not provide instantaneous overlap of the fuel supply lines due to the inertia of the lever system of closing the valve and the free movement of the ball valves.

The objective of the invention is:

- creation of a simple and reliable aircraft fuel system with a suction device that provides continuous fuel supply to the engine at all engine operating modes and at any aircraft positions;

- removal of gas from the consumable compartment;

- improving the filling of the fuel intake pipelines and the fuel compartment with fuel;

- compensation for losses associated with the resistance of the pipeline path;

- creating a device that is sensitive to minimal changes in the position of the aircraft.

The technical result is achieved by the fact that in a fuel system containing a tank, an inertia valve, a flow compartment with a baffle, and fuel intake pipes from the tank, the inertia valve is a cylindrical load located along the axis in the direction of flight and moving axially along balls placed in a separator mounted on an inner sleeve pressed onto a load containing seals at the ends that interact with seats that are opposed to the flanges of the valve body. The flanges are interconnected with emphasis on the outer casing of the movement of the load on the balls. The outer cage at each end contains holes communicating the fuel intake pipes from the tank with the consumable compartment. In the flow compartment, an ejector is used as an air separator and a device for draining the flow compartment, in which the annular chamber of the low-pressure flow is led to the upper extreme zones of the flow compartment in the direction of flight (NP) by means of drainage pipelines, and the high-pressure flow nozzle is connected to the discharge of the working fluid from the aircraft hydraulic system into the consumable compartment. At the outlet of the pipe for draining the working fluid from the aircraft hydraulic system, a diaphragm is installed in the consumable compartment.

The invention is illustrated by drawings. In FIG. one; 2; 3; 4 shows the fuel system of the aircraft.

The fuel system of the invention shown in FIG. 1, consists of a tank 1, an inertial valve 2, a consumable compartment 3, and pipelines 4, 5 for taking fuel from the tank. The state of the hydraulic system is shown in the dive position of the aircraft, indicated by NP.

The inertia valve 2 shown in FIG. 2, contains a cylindrical load 6, balls 7, placed in a separator 8 mounted on an inner sleeve 9, pressed onto a load 6, containing at the ends of the seal 10, 11, interacting with saddles 12, 13, opposite located on the flanges 14, 15 of the housing 16 The flanges 14, 15 are interconnected with a stop on the outer sleeve 17 for moving the load 6 along the balls 7. The outer sleeve 17 from each end contains openings 18 communicating the pipelines 4, 5 with the consumable compartment shown in FIG. 3.

The consumable compartment shown in FIG. 3, contains an ejector 19 with pipelines 20 for drainage of the consumable compartment, a pipeline 21 for discharging the working fluid from the aircraft hydraulic system, a pipe 22 for communication with an inertia valve, a pipe 23 for taking fuel from the consumable compartment to the engine, a partition 24.

The ejector 19 shown in FIG. 4, comprises an annular chamber 25 of low pressure flow with pipelines 20 for drainage of the consumable compartment 3 discharged to the upper extreme zones of the consumable compartment 3 by NP, the nozzle 26 of the high-pressure flow as an element of the pipeline 21 for draining the working fluid from the hydraulic system of the aircraft into the consumable compartment 3, the nozzle 27, forming a cross section of the low-pressure flow through a concentric gap 28 between the nozzle 26, a nut 29, pressing the nozzle 27 through the adjusting gasket 30. At the outlet of the pipeline 21 for draining the working fluid from the aircraft hydraulic system into the consumable compartment, afragma 31 shown in FIG. 3, which determines the flow rate of the working fluid consumed by the ejector.

In addition, excess gas pressure is created in the tank to reduce the natural release of air from the fuel and as a means of cavitation, as well as the spent liquid from the aircraft hydraulic system is drained into the tank (these processes are not considered in the application).

The principle of operation of the fuel system is stated taking into account the provisions of the aircraft in flight.

Convertible flight: fuel due to gravity and overload is shifted to the rear of the tank with the level of the aircraft elevation angle, while leaving the fuel intake pipe 4 open, without fuel. Continuous fuel supply to the engine as a mandatory requirement is ensured in the indicated position by the following operation of the fuel system devices:

- the load 6 of the inertial valve 2 also due to gravity and overload instantly moves along the balls 7 and the outer cage 17 in the opposite direction of flight, blocking the seal 11 on the saddle 13, the gas from the pipeline 4 through the pipe 22 to the consumable compartment 3, opening the flow of fuel through the pipeline 5 through the pipe 22 to the consumable compartment 3 and then through the pipe 23 to the engine.

When flying with a dive, the functioning of the fuel system is similar to that described above: the load 6 of the inertia valve 2 moves in the direction of flight, blocking the seal 10 on the seat 12, the gas from pipeline 5 through line 22 to the flow compartment 3, opening the fuel supply through line 4 through line 22 to the supply compartment 3 and further also through the pipe 23 to the engine.

In case of negative and lateral overloads, the continuous flow of fuel to the engine is ensured by the constant filling of the flow chamber with fuel due to the alternate blocking of gas access to the system, as described above, by guaranteed removal of gas from the flow chamber 3 by the ejector 19; the presence in the flow compartment 3 of the partition 24, restricting the vertical movement of fuel in the flow compartment and improving the occupancy of the cavity of the flow compartment, located below the partition 24, by draining the working fluid from the aircraft hydraulic system. The volume of the consumable compartment fully provides the condition for the continuous supply of fuel to the engine.

For the effective use of the ejector 19 to remove gas from the flow compartment 3 and to improve the fillability of the fuel compartment 3 and the pipe 23, as well as to reduce losses associated with the resistance of the pipeline path, no more than 15% of the drained working fluid from the aircraft hydraulic system is used for high-pressure ejector flow , which is provided by the diaphragm 31, through which the rest of the flow enters the intake cavity of the consumable compartment, improving the occupancy of the consumable compartment. The concentric gap 28 is selected so that the speed of the high-pressure flow of the ejector does not exceed the speed of the low-pressure flow by 10-15%. The principle of operation of the drainage device of the consumable compartment using the ejector 19: high-pressure flow of draining the working fluid from the hydraulic system of the aircraft, leaving the nozzle 26 at a high speed, carries with it the low-pressure flow and through the concentric gap 28, the annular chamber 25 with pipelines 20 removes gas from the consumable compartment 3, which enters into it due to the permissible leak through the seals 10, 11 and transients during movements of the load 6 of the inertial valve 2.

The calculation of the drainage device of the consumable compartment using the ejector based on the calculations according to the book [7. Volkov E.B. Liquid rocket engines: Fundamentals of the theory of rocket engine aggregates and propulsion systems / EB. Volkov, L.G. Golovkov, T.A. Syritsyn. - M: Military Publishing, 1970. - § 6.9. Jet pumps. - S. 297-305. Fig. 6.38, 6.39.].

Initial data:

Minimum flow rate - 0.4 l / s (400 cm ³ / s), pressure - 15 kgf / cm ² flow in the discharge line from the aircraft hydraulic system (used to organize high-pressure flow).

The internal diameter of the hydraulic discharge line is -14 mm.

The leakage of the distributor, taking into account the transient processes of its operation, is 300 cm ³ / min (5 cm ³ / s). For guaranteed removal of gas, the flow rate of the low-pressure flow G _n = 10 cm ³ / s is adopted.

The pressure in the tank is 7 kgf / cm ² .

The pressure in the consumable compartment is 6.5 kgf / cm ² .

1. Determination of the required flow rate of high pressure flow:

For the stable operation of the ejector, the pressure of the stream at its exit (behind the diffuser) is taken to be P _C = 8 kgf / cm ² . In this case, the pressure drops and their ratio will be:

where P _H is the pressure of the low-pressure flow;

P _P - pressure high-pressure flow;

ΔP _H is the pressure change between the low-pressure flow and the flow exiting the ejector;

ΔP _P - pressure change between the high-pressure flow and the flow exiting the ejector.

In accordance with the schedule [7. fig. 6.39] the ratio of ΔP _H / ΔP _P determines the injection coefficient: υ = 1.2. This ratio is the ratio of the low-pressure flow rate G _H to the high-pressure flow G _p :

Considering that this graph is made for a jet pump with flows of the same liquid (compressible gas bubbles are present in the calculated ejector in a low-pressure flow) and taking into account that the losses in the calculated ejector will be higher (a short mixing chamber is structurally made), a reduction coefficient of 0 is adopted. 5. Then the injection coefficient will be 1.2 × 0.5 = 0.6. Therefore, the flow rate of high pressure flow:

Given that the ejection system, in addition to the main task (gas removal), improves the filling of the flow compartment and compensates for hydraulic losses of the fuel supply lines to the flow compartment, and in order to improve fuel supply it is accepted: G _P = 40 cm ³ / s.

This flow rate is ensured by installing a diaphragm with a hole with a diameter of 7 mm in the discharge line from the hydraulic system to the bottom of the flow compartment, providing a flow through it of 360 cm ³ / s (0.36 l / s or 21.6 l / min) with a minimum pressure drop. The specified diameter is determined on the basis of the nomogram for determining the flow rate through the throttle washer presented in the book [8. Abramov E.I. Hydraulic drive elements: Reference book / Abramov, E.I., Kolesnichenko, K.A., Maslov, V.T. - Kiev: Technique. - 1969. - S. 46-50, 145-148.]

2. Determination of geometric characteristics:

The nozzle diameter of the high-pressure flow D is taken to be 14 mm (1.4 cm), i.e. equal to the internal diameter of the hydraulic drain. Flow area fp of high pressure flow:

High-pressure flow rate ω _p :

The concentric gap forming the cross section of the low-pressure flow is assumed to be 1 mm (0.8 to 1 mm is permissible). Minimum flow area f _{H of} low pressure flow:

The low-pressure flow rate ω _n :

which is slightly less than the high-pressure flow rate. In this case, the speeds should level out in the mixing chamber.

, что несколько больше площади проходного сечения низконапорного потока (0,42 см²).The total cross-sectional area of the pipelines of the drainage system with an inner diameter of 6 mm is

that is slightly larger than the flow area of the low-pressure flow (0.42 cm ² ).

Designations:

G _H - low-pressure flow rate;

P _H is the pressure of the low-pressure flow;

ω _H is the low-pressure flow rate;

f _H is the flow area of the low-pressure flow;

G _P - flow rate of high pressure flow;

P _P - pressure high-pressure flow;

ω _p is the velocity of the high-pressure flow;

fp is the flow area of the high-pressure flow;

P _C is the pressure at the outlet of the ejector;

ΔP _H is the pressure change between the low-pressure flow and the flow exiting the ejector;

ΔP _P - pressure change between the high-pressure flow and the flow exiting the ejector.

υ is the injection coefficient.

Technical result:

- the fuel system provides continuous fuel supply to the engine at all engine operating modes and in any aircraft position;

- removal of gas from the consumable compartment;

- improving the filling of the fuel intake pipelines and the fuel compartment with fuel;

- compensation for losses associated with the resistance of the pipeline path;

- the device is sensitive to minimal changes in the position of the aircraft.

The aircraft fuel system can be performed using standard equipment and materials of domestic production, which meets the criterion of "industrial applicability".

Information sources

1. Polikovsky V.I. Aircraft power plants. - M .: Oborongiz, 1952. - 600 p. (S. 54-60, Fig. 28-32; p. 71-72, Fig. 42.44; p. 133-134, Fig. 90; p. 157-160, Fig. 108-111).

2. Polikovsky V.I. Power plants of aircraft with jet engines / V.I. Polikovsky, D.N. Surnov. - M.: Mechanical Engineering, 1965. - 261 p. (S. 20-22; 30-55, Fig. 10, 38, 40).

3. Pat. RU 2523729 C1, IPC B64C 29/00. Fuel system of an unmanned aerial vehicle / Kostkin M.D., Popovich A.M. - Publ. 07/20/2014. Bull. No. 20.

4. Hydraulic systems of high pressures / Ed. Yu.N. Laptev. - M.: Mechanical Engineering, 1973. - 153 p.

5. Pat. RU 2016266 C1, IPC F04 F5 / 54. Pump-ejector installation / Gorodivsky A.V., Roshak I.I., Gorodivsky L.V. - Publ. 07/15/1994.

6. Pat. RU 2366840 C1, IPC F04F 5/30. Ejector / Panchenko V.I., Panchenko O.V., Raskin A.I., Rukavishnikov A.I., Sychenkov V.A., Sharapov L.E. Publ. 09/10/2008. Bull. Number 25.

7. Volkov E.B. Liquid rocket engines: Fundamentals of the theory of rocket engine aggregates and propulsion systems / EB. Volkov, L.G. Golovkov, T.A. Syritsyn. - M.: Military Publishing, 1970 .-- 592 p.

8. Abramov E.I. Hydraulic drive elements: Reference book / Abramov, E.I., Kolesnichenko, K.A., Maslov, V.T. - Kiev: Technique. - 1969. - S. 46-50, 145-148.

9. Pat. RU 2209350 C1, IPC F04F 5/14; B01F 3/04; B05B 7/04. Ejector and method of its operation / Koss A.V., Penzin R.A. Publ. 07/27/2003. Bull. No. 21.

Claims (2)

1. The fuel system of the aircraft, comprising a tank, an inertia valve, a consumable compartment with a baffle, and fuel intake pipes from the tank, characterized in that the inertia valve is a cylindrical load located along the axis in the direction of flight and moving axially along the balls placed in a separator mounted on an inner sleeve, pressed onto a load, containing at the ends of the seal, interacting with seats, opposite located on the flanges of the valve body, flanges They are interconnected with emphasis on the outer cage of moving the load around the balls, the outer cage at each end contains holes communicating the fuel intake pipes from the tank with the consumable compartment. 2. The fuel system according to claim 1, characterized in that an ejector is used in the flow compartment as an air separator and a device for draining the flow compartment, in which the annular chamber of the low-pressure flow through the drain pipes is led to the upper extreme zones of the flow compartment in the direction of flight, and the nozzle high-pressure flow is connected with the discharge of the working fluid from the hydraulic system of the aircraft to the consumable compartment, at the outlet of the pipe for draining the working fluid from the hydraulic system of the aircraft to the consumable compartment aperture set.

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