JP2004090778A - Air conditioner for aircraft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner for aircraft which obtains a required cooling function by reducing the bleed air rate from an engine as much as possible and takes the open air as a part of the bleed air. <P>SOLUTION: When grounding or flying at a low altitude, the engine bleed air is cooled by a primary heat exchanger 3a, and on the other hand, the open air 16 is compressed by a compressor 4a, and cooled by a secondary heat exchanger 5a, and the bleed air and the open air are led into a turbine 10a at the same time, and adiabatically expanded, to lower the temperature of the air, and this low-temperature air is fed to a mixing chamber 11. When flying at a high altitude, the engine bleed air is led to the turbine 10a through the primary heat exchanger 3a, and expanded, while insulating the heat, to lower temperature of the air, and on the other hand, the open air 16 is compressed by the compressor 4a, and passed through a secondary heat exchanger 5a, and a flow rate/surge control valve 17a is opened to feed the compressed open air 16 to an outlet side of the turbine 10a, and fed to the mixing chamber 11 with the low-temperature bleed air, and supplied to a cockpit cabin 12. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air conditioner for an aircraft, and more particularly, to an air cycle system (ACS) that reduces the amount of engine bleed air during ground or low altitude flight.
[0002]
[Prior art]
An air conditioner for an aircraft performs cooling, heating, and ventilation in the cabin (cabin) and supplies pressurized air, and is roughly classified into a pressurized system and a cooling / heating system. In a small machine without a pressurized system, the inside of the machine is heated by heat of an exhaust pipe of an engine or heat from a separately provided heater, and cooling is performed by taking in outside air into the machine. On the other hand, a large-sized machine with a pressurized room extracts a part of high-temperature, high-pressure air from the compressor of the engine (this is called engine freed air or bleed air), and (A) removes cold air outside the machine. (This is referred to as ram air), (B) a vapor cycle cooling system using a refrigerant, or (C) an air cycle cooling system. Air conditioning and heating are being performed. Older large aircraft and current turbine helicopters use a combination of (A) and (B) for the vapor cycle system, and newer jets use a combination of (A) and (C) for the air cycle system. Is adopted.
[0003]
In the conventional apparatus, a method of separating water under a low pressure (referred to as an LPWS method) is used as an air cycle system (referred to as an ACS). However, a large amount of air is extracted from an engine, and an engine or an APU (auxiliary) is used. A power unit, which is bleeding from here when not flying, which is usually provided at the rear of the fuselage) because of its poor fuel efficiency (called a 3-WheelHPWS system) under high pressure. Has been adopted. This 3-Wheel HPWS system is equipped with a fan, a compressor and a turbine for introducing ram air in a single shaft, can remove the humidity in the conditioned air under high pressure, and can lower the ACS outlet temperature to below freezing. Therefore, the amount of bleed air used to obtain the required cooling capacity is smaller than that of the conventional LPWS system, and the fuel efficiency of the engine or the APU is improved. The ACS outlet air is too cold to feed directly into the cabin, so it mixes with some of the exhaust from the cabin that has returned through the recirculation line and is adjusted to a comfortable temperature before being fed to the cabin. Further, when the cooling capacity is insufficient with the ACS alone, a vapor cycle system (VCS and VCS) having a cooling device using a refrigerant or the like is provided independently of the ACS for cooling the mounted electronic devices and the like. ) Is provided for cooling.
[0004]
FIG. 3 shows a conventional air conditioner system for an aircraft. On the ground or at a low altitude, the air extracted from the engine 1 is adjusted by the extraction control valve 2, the valve 21 is opened, the valves 22 and 23 are closed, and the air is input to the ACS 19. The humidity in the conditioned air is removed by the ACS 19, and air near the freezing point is introduced into the mixing chamber 11 from the outlet of the ACS 19. At a high altitude above the air, the valve 21 is closed and the valves 22 and 23 are opened to take in the high-temperature and high-pressure air extracted from the engine 1 and a part of the air from the outside air 16, and to harmony with the ACS 19. The humidity in the air is removed, and air near the freezing point is introduced into the mixing chamber 11 from the outlet of the ACS 19. On the other hand, warm air exhausted from the cockpit cabin 12 by the recirculation fan 13 and the control valve 14 is introduced into the mixing chamber 11 through the recirculation line, and mixed with air near the freezing point introduced from the ACS 19 to provide a comfortable air. After being adjusted to the temperature, it is introduced into the cockpit cabin 12. Further, when the cooling capacity is insufficient with the ACS 19 alone, a VCS (not shown) is provided independently of the ACS 19, and cools mounted electronic devices and the like. An outflow valve (not shown) is provided for automatically adjusting the pressure in the cockpit cabin 12 to a predetermined comfortable pressure, and the air is automatically controlled to exhaust excess air to the outside.
[0005]
Next, the operation of the ACS 19 will be described. A part of the air which has become high temperature and high pressure in the engine is adjusted in pressure by the bleed control valve 2 and taken out, and is inputted to the ACS 19.
In the ground or low altitude flight, the valve 21 was opened, the valves 22 and 23 were closed, and the extracted air was cooled by the primary heat exchanger 3 cooled by the ram air 6 filled with cool air. Thereafter, the gas is compressed by the compressor 4 via the valve 21 and cooled again by the secondary heat exchanger 5, and a part of the steam is condensed. On the other hand, the ram air 6 is discharged to the outside by the fan 7. The air cooled by the secondary heat exchanger 5 enters the high-temperature circuit of the repeater 8 and is cooled by heat exchange of the cooled air from the condenser 9 with the low-temperature circuit. The high-pressure air that has exited the reheater 8 is further cooled in the condenser 9 by the low-temperature air that has been adiabatically expanded in the turbine 10, and almost all of the water vapor contained therein is condensed. The air that enters the turbine 10 through the reheater 8 and exits the turbine 10 undergoes heat exchange with the air from the reheater 8 in the condenser 9 and is guided to the mixing chamber 11 at 0 ° C. or lower.
In the high altitude flight, the valve 21 is closed, the valves 22 and 23 are opened, and high-temperature and high-pressure air is extracted from the engine 1, and part of the air from the outside air 16 is taken into the ACS 19. Then, the extracted high-temperature air is cooled by the ram air 6 in the primary heat exchanger 3 and sent directly to the turbine 10 via the valve 23. The air taken in from the outside air 16 is compressed by the compressor 4 via the valve 22, further cooled by the ram air 6 in the secondary heat exchanger 5, enters the high-temperature circuit of the reheater 8, and is cooled by the condenser 9. The air is further cooled by heat exchange with the low-temperature side circuit. The high-pressure air exiting the reheater 8 and the air sent from the primary heat exchanger 3 by bleed air via the valve 23 are simultaneously adiabatically expanded in the turbine 10 and heat-exchanged with the air from the reheater 8 in the condenser 9. , 0 ° C. or lower.
Further, when the cooling capacity is insufficient with the ACS 19 alone, the vapor cycle system VCS having a cooling device using a refrigerant such as chlorofluorocarbon, independently of the ACS 19, for cooling the electronic devices mounted thereon is used. (Not shown).
As described above, a conventional large-sized aircraft air conditioner extracts a portion of the high-temperature and high-pressure air from the compressor of the engine (bleed air) and uses the cool air outside the machine (ram air) to generate air / air. The air conditioning is performed mainly by the cycle system and supplementarily and independently using the vapor cycle system.
[0006]
[Problems to be solved by the invention]
The conventional aircraft air conditioner is configured as described above. However, in ground or low altitude flight, air for air conditioning is taken in from an engine bleed into ACS 19 (air cycle system) and supplied, and high altitude flight is performed. In, in addition to the engine bleed, part of the outside air 16 is taken into the ACS 19 to reduce the engine bleed. By reducing the engine bleed, the amount of bleed used to obtain the required cooling capacity can be reduced, and the fuel economy of the engine (or APU) 1 can be improved. Therefore, there is a problem whether it is possible to reduce the engine bleed air even on the ground or at a low altitude flight. In ground or low-altitude flight and high-altitude flight, there is a problem that the ACS 19 needs to be modified in order to obtain the required cooling capacity by reducing the amount of bleed air as much as possible.
[0007]
The present invention has been made in view of such circumstances, and even on a ground or low altitude flight, the amount of engine bleed air from the engine (or APU) is reduced as much as possible, and a part of the air bleed is required from outside air. It is an object of the present invention to provide an air conditioner for an aircraft capable of obtaining a capability.
[0008]
[Means for Solving the Problems]
To achieve the above object, the aircraft air conditioner of the present invention extracts a portion of high-temperature, high-pressure air from a compressor of an aircraft engine, utilizes cold air outside the aircraft, and uses an air cycle system. An air conditioning system for aircraft that air-conditions the cabin.In ground or low altitude flight, engine bleed air passes through a primary heat exchanger using ram air cooling, while outside air is compressed using a compressor and passes through a secondary heat exchanger using ram air cooling. In high altitude flight, engine bleed air flows from the dual nozzle through the primary heat exchanger using ram air cooling, while the external air is compressed by the compressor and the bleed air and outside air are compressed using the compressor. An air cycle system that feeds through the secondary heat exchanger to the turbine outlet and removes some of the supply air. It is obtained to be able to reduce the engine bleed amount by taking the.
[0009]
The aircraft air conditioner of the present invention is configured as described above, and on ground or low altitude flight, engine bleed air is passed through the primary heat exchanger, while outside air is compressed by the compressor and cooled through the secondary heat exchanger. The extracted bleed air and the outside air flow into the turbine from separate nozzles (dual nozzles), adiabatically expand, and condense almost all of the steam contained in the low-temperature air.
In high altitude flights, the engine bleed air passes through a primary heat exchanger and into the turbine through nozzles where it is adiabatically expanded, condensing almost all of the water vapor contained in the cold air. On the other hand, low-pressure outside air is compressed by a compressor, a flow rate / surge control valve is opened through a secondary heat exchanger and sent to the outlet side of the turbine, and sent to the mixing chamber together with the bleed air which has been cooled to be supplied to the cockpit cabin.
In ground or low-altitude flight, engine bleed air is cooled by the adiabatic expansion of the primary heat exchanger and turbine. Since the temperature can be lowered by adiabatic expansion of the turbine, a part of the outside air can be taken in, the amount of extracted air can be reduced, and the cooled air can be supplied.
In high-altitude flights, engine bleed air is cooled by adiabatic expansion of the primary heat exchanger and turbine, while outside air, which has a lower temperature than the ground and has low pressure, is compressed by a compressor and cooled by a secondary heat exchanger. By opening the flow / surge control valve and sending it directly to the outlet side of the turbine and sending it to the mixing chamber together with the cooled bleed air, it takes in some outside air and reduces the amount of bleed air to reduce the cooled air. Can be supplied.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the aircraft air conditioner of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a system diagram of an air conditioner for an aircraft of the present invention. The air conditioner for an aircraft of the present invention includes an ACS (air cycle system) 19a for taking in air from the engine (or APU) 1 and taking in air from outside air 16 to cool and dehumidify the air, and a part of the air in the cockpit cabin 12. It comprises a recirculation flow path for taking out and recirculating, and a mixing chamber 11 for mixing low-temperature air from the ACS 19 a and warm air from the recirculation flow path and supplying the mixed air to the cockpit cabin 12.
[0011]
The difference between the present air conditioner and the conventional device is that, at the time of ground or low altitude flight, the conventional device uses the primary heat exchanger 3 to extract air from the engine (or APU) 1 as shown in FIG. Although the compressor 4, the secondary heat exchanger 5, and the turbine 10 keep the temperature low, in the present apparatus, the engine bleed air is passed through the primary heat exchanger 3a, while the high-pressure external air 16 whose temperature is relatively high as compared to the sky is discharged. The intake air is passed through the compressor 4a and the secondary heat exchanger 5a, and the bleed air and the outside air 16 are sent from the dual nozzle 20a to the turbine 10a to be cooled to be supplied to the mixing chamber 11.
In this device, the engine bleed air is passed through the primary heat exchanger 3a to the turbine 10a without passing through the compressor 4a and the secondary heat exchanger 5a, and a part is supplied from the outside air 16 using only cooling by adiabatic expansion. I have. As described above, in the present apparatus, during the ground or low-altitude flight, part of the outside air 16 is taken in, the engine bleed air is reduced, and the fuel efficiency of the engine (or APU) 1 is improved.
[0012]
In high altitude flight, in the conventional apparatus, as shown in FIG. 3, the engine bleed air is passed through the primary heat exchanger 3, the valve 23, and the turbine 10, while the outside air 16 is passed through the valve 22, the compressor 4, and the secondary heat exchange. Although the temperature is lowered by passing through the heat exchanger 5 and the turbine 10, in this apparatus, the engine bleed air is passed through the primary heat exchanger 3 a, the dual nozzle 20 a, and the turbine 10 a, while the low pressure outside air 16 having a high altitude and a low temperature is taken in. The air passes through the compressor 4a and the secondary heat exchanger 5a. However, since the flow is reduced due to the low pressure, the check valve 18a is closed, and the flow rate / surge control valve 17a is opened. It flows to the outlet of the turbine 10a and is supplied to the mixing chamber 11 together with the cooled bleed air. As described above, the two devices have different systems during high-altitude flight, but partially take in outside air 16 to reduce engine bleed air.
[0013]
Next, the operation of the aircraft air conditioner and the configuration of each part will be described. The ACS (Air Cycle System) 19a is a ram air taken from the engine (or APU) 1 via a bleed control valve 2 when high-temperature and high-pressure engine bleed air is taken from the engine (or APU) 1 during ground or low altitude flight. The heat is exchanged and cooled in the primary heat exchanger 3a cooled by the cooling. On the other hand, the outside air 16 having a higher temperature and a higher pressure than the sky is compressed by the compressor 4a and heat-exchanged and cooled by the secondary heat exchanger 5a cooled by the ram air taken in from the outside air. With the flow / surge control valve 17a closed, the cooled outside air 16 passing through the check valve 18a is sent from the dual nozzle 20a to the turbine 10a together with the cooled bleed air. Almost all of the contained steam is condensed by the low-temperature air adiabatically expanded in the turbine 10a. Then, it is guided to the mixing chamber 11 at 0 ° C. or lower.
Also, the ACS (air cycle system) 19a is configured such that during high altitude flight, high-temperature and high-pressure engine bleed air is taken in from the engine (or APU) 1 via the bleed control valve 2 and ram air taken from outside air is used. The heat is exchanged and cooled by the cooled primary heat exchanger 3a, and sent to the turbine 10a from the dual nozzle 20a. Then, it is adiabatically expanded by the turbine 10a to become low-temperature air. On the other hand, the high-altitude, low-temperature, low-pressure outside air 16 is taken into the compressor 4a and compressed, and heat-exchanged and cooled by the secondary heat exchanger 5a cooled by the ram air taken from the outside air. At this time, if the flow becomes low due to the low pressure and the flow rate decreases, the compressor 4a becomes a surge. Therefore, the check valve 18a is closed, the flow rate / surge control valve 17a is opened, and the cooled outside air 16 flows into the turbine 10a. The air is supplied to the mixing chamber 11 together with the cooled bleed air that has flowed to the outlet. The flow rate / surge control valve 17a prevents the compressor 4a from entering a surge by flowing a flow rate at the outlet of the turbine 10a, and at the same time plays a role of adjusting the flow rate to the mixing chamber 11 to an appropriate value.
The recirculation passage section is a passage for taking out a part of the warm air in the cockpit cabin 12 and recirculating it to the mixing chamber 11, and includes a recirculation fan 13 and a control valve 14. The amount of recirculated air is controlled by adjusting the rotation speed of the recirculation fan 13 and the opening of the control valve 14.
In the mixing chamber 11, the high-temperature and high-pressure air of the engine bleed air and part of the air from the outside air 16 are taken into the ACS 19 a, the humidity is removed during the air conditioning, and the air near the freezing point is discharged from the outlet to the mixing chamber 11. On the other hand, warm air taken in from the cockpit cabin 12 by the recirculation fan 13 in the recirculation flow path section is introduced into the mixing chamber 11 through the recirculation line via the control valve 14 to mix the two airs. After being adjusted to a comfortable temperature, it is introduced into the cockpit cabin 12.
[0014]
FIG. 2 shows another embodiment of the aircraft air conditioner. In FIG. 2, the components denoted by the same reference numerals as those in FIG. 1 have the same functions, and thus detailed description is omitted. In this apparatus, the compressor 4b, the turbine 10b, and the fan 7b are coaxially provided, and the ram air 6b is taken in by the fan 7b to cool the secondary heat exchanger 5b and the primary heat exchanger 3b. The outlet is provided with a water separator 15b. The water separation may be either low pressure separation (LPWS) or high pressure separation (HPWS).
During ground or low altitude flight, high temperature / high pressure engine bleed air from the engine (or APU) 1 is taken in via the bleed control valve 2 and cooled by the ram air 6b taken from outside air by the primary heat exchanger 3b. , Heat exchange and cooling. On the other hand, the outside air 16 having a higher temperature and a higher pressure than the sky is compressed by the compressor 4b, and heat-exchanged and cooled by the secondary heat exchanger 5b cooled by the ram air 6b taken in from the outside air. With the flow / surge control valve 17b closed, the cooled outside air 16 passes through the check valve 18b and is sent from the dual nozzle 20b to the turbine 10b together with the cooled bleed air. In the low-temperature air adiabatically expanded in the turbine 10b, almost all of the steam contained in the water separator 15b is condensed, and the water is removed. Then, it is guided to the mixing chamber 11 at 0 ° C. or lower.
In addition, the ACS (air cycle system) 19b is configured such that in high altitude flight, high-temperature and high-pressure engine bleed air is taken in from the engine (or APU) 1 via the bleed control valve 2 and ram air 6b taken from outside air. The heat is exchanged and cooled by the primary heat exchanger 3b, which has been cooled by the above, and sent to the turbine 10b from the dual nozzle 20b. Then, in the low-temperature air adiabatically expanded in the turbine 10b, almost all of the steam contained in the water separator 15b is condensed, and the water is removed. On the other hand, the low altitude outside air 16 having a high altitude and a low temperature is taken into the compressor 4b, compressed, and heat-exchanged and cooled by the secondary heat exchanger 5b cooled by the ram air 6b. At this time, the flow rate decreases, and the low pressure makes it difficult to flow to the turbine 10b. If the flow rate decreases, the compressor 4a becomes surged. 16 flows to the outlet of the water separator 15b and is supplied to the mixing chamber 11 together with the cooled bleed air.
[0015]
【The invention's effect】
The air conditioner for an aircraft of the present invention is configured as described above.In ground or low altitude flight, engine bleed air is cooled by a primary heat exchanger, while outside air is compressed by a compressor and cooled by a secondary heat exchanger. Then, the bleed air and the outside air flow into the turbine at the same time, adiabatically expand to low-temperature air, and are sent to the mixing chamber.In high altitude flight, the engine bleed air flows into the turbine through the primary heat exchanger and adiabatically expands to produce low-temperature air. Air, while outside air is compressed by a compressor and passed through a secondary heat exchanger, the flow / surge control valve is opened, sent to the outlet side of the turbine, sent to the mixing chamber together with the cooled bleed air, and supplied to the cockpit cabin In this way, it is possible to take in some outside air and reduce the amount of bleed air used to obtain the required cooling capacity, Or it is possible to improve the fuel efficiency of the APU).
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an air conditioner for an aircraft of the present invention.
FIG. 2 is a view showing another embodiment of the aircraft air conditioner of the present invention.
FIG. 3 is a diagram showing a flow rate circuit of a conventional aircraft air conditioner.
[Explanation of symbols]
1. Engine (or APU)
2 Bleed control valve 3, 3a, 3b Primary heat exchanger 4, 4a, 4b Compressor 5, 5a, 5b Secondary heat exchanger 6, 6b Ram air 7, 7b Fan 8 Reheater 9 Condenser 10 10a, 10b Turbine 11 Mixing chamber 12 Cockpit cabin 13 Recirculation fan 14 Control valve 15b Water separator 16 Outside air 17a, 17b Flow / surge control valves 18a, 18b Check valves 19, 19a , 19b ... ACS
20a, 20b ... dual nozzle 21, 22, 23 ... valve

Claims (1)

An air conditioner for aircraft that extracts part of high-temperature, high-pressure air from the compressor of an aircraft engine, uses cold air outside the aircraft, and air-conditions the interior of the aircraft using an air cycle system. In flight, the engine bleed air passes through a primary heat exchanger with ram air cooling, while the outside air is compressed by a compressor and passes through a secondary heat exchanger with ram air cooling, and bleed air and outside air flow into the turbine from dual nozzles. Describes an air cycle system in which engine bleed air enters the turbine through a primary heat exchanger with ram air cooling from a dual nozzle, while external air is compressed by a compressor and sent to the outlet side of the turbine through a secondary heat exchanger with ram air cooling. By extracting part of the supply air from outside air, the amount of engine bleed air can be reduced. Aircraft air-conditioning system being characterized in that the so that.

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