RU2840887C1 - Air conditioning system for supersonic civil aircraft - Google Patents

Abstract

FIELD: aircraft air conditioning systems.

SUBSTANCE: air conditioning system for supersonic civil aircraft comprises sequentially located air preparation system, an air cooling unit (ACU) and an air recirculation system. Air preparation system includes electric supercharger (KM1,2) with cooling of electric motor and its fuel control system, air-to-air heat exchanger (AT), electric fan (EV1,2), air flow sensor (DRP1,2), bypass flaps and check valves (KO1,2,3,4). Air cooling unit consists of: turbo-cooler with turbine controlled nozzle assembly, unit of fuel-air heat exchangers, unit of loop air-to-air heat exchangers, moisture separator, located before turbo-cooler turbine stage, bypass flaps and air flow control. Air recirculation system includes fan with controlled rotation frequency.

EFFECT: improving energy efficiency.

2 cl, 4 dwg

Description

The invention relates to air conditioning systems (ACS) of aircraft, primarily supersonic civil aircraft (SCA), and solves the problem of creating and maintaining specified air parameters at the outlet of the ACS throughout the entire range of operation.

For normal operation of the crew and equipment, it is necessary to supply pre-prepared working air with the required values of temperature, pressure and other parameters to the cabin and technical compartments.

The most common variant of the SCS of aircraft (LA) at present are systems with the selection of working air from the compressors of the aircraft engines with subsequent processing of this air to the required parameters. In the absence of the possibility of using compressed air from the compressors of the aircraft engines, it becomes necessary to create a SCS with an autonomous source of compressed air.

Considering the high temperature of the adiabatically decelerated oncoming air flow during supersonic flight of the SGS, its use as a coolant for cooling the electric motor of the electric supercharger and its control system and for cooling the air in the heat exchangers of the second cooling cascade of the SCS does not allow obtaining the required air temperature for supply to the pressurized cabin. In this regard, it is advisable to use the fuel available on board the SGS as a coolant for the specified purposes.

An air conditioning system is known from the prior art (patent US 7322202 B2), which includes an air conditioning unit for receiving compressed air and converting pressurized air into conditioned air for an aircraft. The pressurized air is supplied by a pressurized air supply system to the air conditioning unit. The pressurized air supply system includes a blower powered by an electric motor. The air conditioning unit contains a heat exchanger, an air cycle machine having a compressor and a turbine, and a condenser.

A technical solution is known for the long-range Boeing-787 aircraft's air conditioning system, which includes a system for supplying pressurized cabin air with electrically driven superchargers (Electronic journal Aero QTR_04 2007, Boeing, pp. 6-11).

The disadvantage of the two listed solutions is the use of an electric supercharger, its control system and air in the heat exchangers of the second stage of cooling the outside air for cooling the electric motor, which does not ensure the operability of the SGS SCS in the supersonic flight mode.

An air conditioning system is known according to patent RU 2637080, which contains primary and secondary heat exchangers, loop heat exchangers and a main turbo cooler. The system additionally contains a bypass pipeline connected through a damper after the primary heat exchanger, and containing an additional turbo cooler connected at the compressor inlet and at the turbine inlet to the air bleed pipeline from the engine, wherein the compressor outlet is included in the main pipeline before the secondary heat exchanger, and the turbine outlet is connected to the atmospheric pressure zone. Ensuring a sufficient degree of air compression in the turbo cooler compressor at a reduced pressure of the air entering the system is achieved.

The disadvantage of the system under consideration is the absence of a bypass line for the moisture separation loop, which leads to:

- to heating of air in the loop without separation of moisture during cruising flight due to practically dry atmospheric air;

- to an increase in the hydraulic resistance of the outlet section of the air cooling unit.

Of interest is a system for replacing an engine-powered air conditioning unit with an electric air conditioning unit in an aircraft (US 9617005 B1).

For this purpose, an electric compressor, evaporator and condenser fan are installed. Heat exchange units are installed in the areas of the aircraft that need to be cooled. The air conditioning system has two circulation circuits. In the cooler circuit, the refrigerant circulates between the electric compressor, evaporator and condenser. This cools the evaporator. The evaporator is then used to cool the circulating liquid refrigerant. The coolant circulates in the heat exchangers of the system.

The disadvantage of the presented technical solution is: the use of a vapor compression cycle air cooling unit in the air conditioning system, which is more energy efficient than an air cycle air cooling unit, but has a greater weight and dimensions, more stringent requirements for the tightness of the system, more stringent requirements for the arrangement of units, requiring more frequent maintenance during operation.

Also known is an air conditioning system according to patent US 2013160472 A1, which includes a compressed air branch for transferring externally supplied and compressed air, preferably bleed air. In addition, a cooling circuit is provided for supplying preferably a liquid coolant, which passes through a pressure air duct. The system also includes a first heat exchanger for heat transfer between the compressed air branch and the cooling circuit, a compressed air turbine located in the compressed air branch, and a cooling circuit compressor located in the cooling circuit and mechanically connected to the compressed air turbine. The system can have a modular design and be located in optimal places of the aircraft due to the separation of the compressed air and cooling circuits.

The disadvantages of this system include:

- increased requirements for the reliability of a three-wheel turbocharger of complex design with stages operating on refrigerant and air and optionally with an electric drive;

- increased requirements for tightness, since if the refrigerant leaks in the heat exchangers with liquid refrigerant, the conditioned air will not be cooled, the refrigerant-driven turbine will not produce power and the air conditioning system will fail;

- the use of outside air for cooling in the heat exchangers of the second cooling stage, which does not allow for the necessary air temperature to be supplied to the cabin during supersonic flight of the SGS.

Also known is an air conditioning system according to patent RU 2807448, containing an air preparation system consisting of an interconnected electric supercharger, an air-to-liquid cryogenic pre-cooling heat exchanger, an air cooler pump and a unit for measuring the flow rate of the air being prepared, an air cooling unit consisting of an interconnected four-wheel turbo-refrigerator, a main air-to-air heat exchanger, a block of loop air-to-air heat exchangers, moisture separators, an air-to-liquid cryogenic heat exchanger for thermal stabilization, bypass and air flow control flaps and an air recirculation system.

The disadvantages of this system include:

- the air cooling unit uses a four-wheel turbo-refrigerator that is difficult to regulate and less reliable;

- to cool the electric motor and the control system of the electric supercharger, outside air is used in the heat exchanger of the second stage to cool the conditioned air, which does not allow for the necessary air temperature to be supplied to the pressurized cabin;

- the possibility of using such a scheme only if there is a cryogenic agent on board.

The closest solution in technical essence to the claimed object is an air conditioning system (patent US 20220144438), which includes, depending on the design of the turbo-refrigerator, two or three heat exchangers in which the conditioned air is cooled using the fuel available on board the aircraft. Depending on the version, the system includes one two-wheeled turbo-refrigerator, or two two-wheeled turbo-refrigerators connected in series, or a three-wheeled turbo-refrigerator, or a four-wheeled turbo-refrigerator. Separation of moisture from the air is carried out in a high-pressure loop.

The disadvantages of this system are:

- air for the system is taken from the engine or auxiliary power unit, which has a negative impact on the energy efficiency of the system and the fuel efficiency of the aircraft;

- the use of parallel cooling of conditioned air with fuel in heat exchangers, which leads to an increase in the required fuel consumption for the needs of the system;

- the absence of a bypass line for the moisture separation loop, which leads to heating of the air in the loop without separating moisture during cruising flight due to practically dry atmospheric air and to an increase in the hydraulic resistance of the outlet section of the air cooling unit.

The technical result of the proposed invention consists in increasing the energy efficiency of the SCS in the entire range of operation.

The stated technical result is achieved due to the fact that in the air conditioning system for the preparation of compressed air an electric supercharger with cooling of the electric motor and its fuel management system is used, the air is cooled by the main heat exchanger and the turbine stage of the turbo-cooler with an adjustable nozzle apparatus or by cooling only in the air-to-air heat exchanger, for the operation of the SCS the air extraction from the aircraft engines is excluded, the air cooling unit contains a pipeline for bypassing the turbine stage, a block of loop heat exchangers and a moisture separator.

Additionally, the declared SCS may contain an air flow control unit, located between the air preparation system and the air cooling unit, and consisting of an air flow control damper and an air flow measurement unit.

The design features of the declared SCS are:

1. An electric supercharger is used to prepare compressed air. This solution increases the energy efficiency of the ACS by using a more optimal source of air preparation compared to the engine and the auxiliary power unit of the aircraft. The consequence of increasing the energy efficiency of the air conditioning system will be an increase in the fuel efficiency of the APU;

2. Air cooling is carried out by means of an air-to-air heat exchanger, a block of fuel-to-air heat exchangers and a turbo-refrigerator turbine stage with an adjustable nozzle apparatus, or by means of an air-to-air heat exchanger and a block of fuel-to-air heat exchangers, which ensures cooling modes that are optimal in terms of energy consumption, which leads to an increase in the energy efficiency of the SCS and an increase in the fuel efficiency of the SGS;

3. The air cooling unit contains a bypass pipeline for the loop heat exchanger unit and a moisture separator, which, at high-altitude/cruise modes of operation of the air cooling unit, under conditions of low moisture content in the atmospheric air, allows for a reduction in hydraulic losses along the working air path and thereby a reduction in energy costs for obtaining compressed air with the same parameters, eliminating the heating of the working air from the use of a loop moisture separation system, which in combination will lead to an increase in the energy efficiency of the air cooling unit and an increase in the fuel efficiency of the air cooling system.

The proposed invention shows only those devices and circuits of the ACS that form air circuits. Computing means, resources of the digital control system and details of the ACS control algorithms are not considered. It is assumed that the information and computing capabilities of prospective aircraft and currently tested devices for monitoring and controlling the ACS, actuators in air circuits guarantee the control tasks in the proposed invention, since such tasks are typical for existing ACS.

The claimed invention will be further described with reference to the drawings:

Fig. 1.1-1.2 - Structural diagram of one of the identical duplicating subsystems of the air conditioning system, located on the right and left sides of the aircraft, where SPV1, SPV2 - air preparation system, UOV1, UOV2 - air cooling unit, VRS - air distribution network, KM1(2) - electric supercharger, AT1(2) - air-to-air heat exchanger, AT3(4) - fuel-to-air heat exchanger (FAHE) unit, AT5(6) - air-to-air loop heat exchanger unit; TX1(2) - turbo cooler, VD1(2) - moisture separators, OR1(2) - nozzles, EV1 (2), EV3, - electric fans, F1, - filter, OK1 - ozone converter, BU1 - control unit, KC1, KC3, - concentrators, ZRU1(2), ZRU3, ZRU5(6), ZRU7(8), ZRU9(10) - shut-off and control dampers, ZU1 - shut-off damper, DRP1 (2), DRP3 - air flow sensors, KO1(2), KO3(4), KO5(6), KO7, KO9, KOP - check valves, DD1(2), DD3(4), DD5(6), DD7, DD9(10) - pressure sensors, DPD1(2), DPD3, DPD5(6) - differential pressure sensors, DT1(2), DT3(4), DT5(6), DT7(8), DT9, DTP, DT13(14), DT15(16), DT17(18), DT19, DT21 - temperature sensors, SD1(2) - pressure alarms.

Fig. 2 - Structural diagram of the air preparation system (APS).

Fig. 3 - Structural diagram of the air cooling unit (ACU).

The air conditioning system for a supersonic civil aircraft (Fig. 1.1 - Fig. 1.2) contains the following sequentially arranged:

- an air preparation system (Fig. 2), which includes at least one electric supercharger (KM1(2)) with cooling of the electric motor and its fuel management system, one air-to-air heat exchanger (AT1(2)), one electric fan (EV1(2)), one air flow sensor (DRP1(2)), two bypass flaps (ZRU1(2)) and two check valves (KO1(2));

- an air cooling unit (Fig. 3), consisting of at least a turbo-cooler (TX1(2)) with an adjustable turbine nozzle apparatus, a block of fuel-air heat exchangers (AT3(4)), a block of loop air-air heat exchangers (AT5(6)), a moisture separator (VD1(2)), located in front of the turbo-cooler turbine stage, bypass and air flow regulation flaps ZRU5(6), ZRU7(8), ZRU9(10);

- an air recirculation system, the main unit of which is a fan (EVZ) with adjustable rotation speed, controlled by control units based on signals from air parameter sensors installed in the SCS.

An explanation of the operation of the SGS SCV is given using the example of one of the equivalent duplicating subsystems of the SCV (Fig. 1.1 - Fig. 1.2, Fig. 2, Fig. 3).

1. Air preparation system (APS) (Fig. 1.1 - Fig. 1.2, Fig. 2)

Air enters the system from the atmosphere through a special air intake. Then the air enters the electric supercharger (KM1(2)) (Fig. 1, Fig. 2, Fig. 3), where it is compressed.

At the input and output of the electric supercharger (KM1(2)) there are absolute pressure sensors (DD1(2)) and (DD3(4)) respectively, when the pressure is exceeded, the electric supercharger (KM1(2)) is switched off by the control unit (BU1). At the output of (KM1(2)) there are temperature sensors (DT1(2)), (DT3(4)). When the permissible temperature at the output of the electric supercharger (KM 1(2)) is exceeded, it is switched off by the control unit (BU1) of the SCS.

Bypass dampers (ZRU1(2)) are designed to protect against surge of the electric supercharger (KM1(2)) and to heat the air in the heating mode at low ambient temperatures at low temperatures (at the outlet of the electric supercharger (KM1(2)).

To measure air flow, a flow sensor (DRP1(2)) is used together with absolute pressure sensors (DD5(6)), differential pressure sensors (DPD1(2)), temperature sensors (DT5(6)), (DT7(8)), a flow sensor (DRP3) together with absolute pressure sensors (DD7), differential pressure sensors (DPD3), temperature sensors (DT9), (DT11).

The pressure alarm (SD1(2)) is designed to switch off the SCS when the permissible pressure is exceeded in the event of failure of the absolute pressure sensors (DD3(4)). The check valves (KO1(2)), (KO3(4)) are designed to prevent backflow of air.

The air heated in the electric blower (KM1(2)) is cooled in the heat exchanger (AT1(2)) by outside air. On the ground, the purge air is supplied to the heat exchanger (AT 1(2)) by the electric fan (EV1(2)); at altitude, the purge is carried out mainly by means of the high-speed pressure of the oncoming air flow through a bypass line with a check valve (KO3(4)).

Cooling of the electric supercharger (KM1(2)) is carried out by fuel from the fuel line.

2. Air cooling unit (ACU) (Fig. 1.1 - Fig. 1.2, Fig. 3)

To remove ozone, the air passes through ozone converters (OKI).

The dampers (ZRU3) regulate the air flow through the SCS.

The valve (ЗУ1) opens and closes the pipeline ring line.

Next, the air enters section 1 of the TVT unit (AT3(4)), where it is cooled by fuel coming from section 2 of the TVT unit. Then the air is compressed in the turbo cooler (TX1(2)) and then enters section 2 of the TVT unit for cooling, where it is cooled by fuel coming from the fuel line. The check valve (KO5(6)) is designed to bypass the turbo cooler (TX1(2)) in order to facilitate its start-up in the case of using gas-dynamic supports in the design.

When the permissible temperature at the outlet of the turbo-cooler (TX1(2)) measured by the temperature sensors (DT13(14)), is exceeded, the SCR unit (BU3) switches off the SCR. The temperature sensor (DT15(16)) is designed to measure the temperature behind the TVT unit (AT3(4)) to be able to regulate the fuel consumption through the TVT unit (AT3(4)) based on its readings.

The circuit provides for moisture separation in the high-pressure loop, which includes the VVT unit (AT5(6)), consisting of a superheater, a condenser, and a moisture separator (VD1(2)). The final cooling of the air occurs in the turbo-refrigerator turbine (TX1(2)) . The temperature sensor (DT17(18)) measures the temperature behind the moisture separator (VD1(2)) to maintain it above zero.

The moisture separated in the moisture separator (VD1(2)) with the help of the sprinkler (OR1(2)), is injected into the scavenging tract of the air-to-air system (AT1(2)) to use evaporative cooling in order to increase the efficiency of the air-to-air system.

The temperature at the outlet of the air cooling unit (ACU) is maintained using the dampers (ZRU5(6)), (ZRU7(8)) . These dampers open sequentially. If it is necessary to increase the temperature behind the ACU, the damper (ZRU7(8)) opens. When it is fully open and the temperature at the outlet of the ACU has not increased sufficiently, the damper (ZRU5(6)) opens.

The damper (ZRU5(6)) is also used for defrosting the condenser. This damper opens and lets hot air through when the hydraulic resistance of the VVT unit condenser (AT5(6)) is exceeded when it freezes. The hydraulic resistance of the condenser is measured by the differential pressure sensor (DPD5(6)).

The damper (ZRU9(10)) bypasses the loop at high altitudes, when the working air is practically dry, in order to reduce the hydraulic resistance of the outlet section of the system and eliminate cold losses in the loop.

3. Air recirculation system

The air recirculation system is a complex of units for cleaning and supplying air used by consumers for reuse in the SCS (Fig. 1.1 - Fig. 1.2).

With the help of electric fans (EV3), recirculated air from the cabin, purified in filters (F1), is mixed in.

After mixing with recirculated air, the air from the UOV enters the manifold and then the distribution system, which supplies air to the cockpit, passenger cabin, toilets, and galley. The air supplied to the cockpit is additionally humidified.

The SCS interacts with the aircraft's propulsion systems through electrical interfaces, receiving power from the aircraft's power supply system (PSS).

Claims (5)

1. An air conditioning system for a supersonic civil aircraft, characterized in that it contains the following sequentially arranged: - an air preparation system, which includes at least one electric supercharger with cooling of the electric motor and its fuel management system, one air-to-air heat exchanger, one electric fan, one air flow sensor, two bypass flaps and two check valves; - an air cooling unit consisting of at least a turbo-cooler with an adjustable turbine nozzle apparatus, a block of fuel-air heat exchangers, a block of loop air-air heat exchangers, a moisture separator located in front of the turbo-cooler turbine stage, bypass flaps and air flow regulation; - an air recirculation system, the main unit of which is a fan with adjustable rotation speed, controlled by control units based on signals from air parameter sensors installed in the air handling unit. 2. An air conditioning system for a supersonic civil aircraft according to paragraph 1, characterized in that it additionally contains an air flow control unit located between the air preparation system and the air cooling unit and consisting of an air flow control damper and an air flow measurement unit.