JP2004314654A - Air conditioning system for aircraft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioning system for an aircraft which improves the cooling performance by an air bleed pressure, effectively cools mounted appliances, and eliminates freezing in a capacitor. <P>SOLUTION: A high temperature/high pressure air bleed from an engine 1 is compressed by a compressor 2, and introduced to a primary heat exchanger 4 by a ram air refrigeration, and compressed by a compressor 5 and introduced to a secondary heat exchanger 6. A cooling liquid which cools an electronic appliance 25 is circulated to a primary liquid cold heat-exchanger 28 and a secondary liquid cold heat-exchanger 29 by a pump 26. The air bleed from the secondary heat-exchanger 6 is introduced to the secondary liquid cold-heat exchanger 29 and the capacitor 8, and cooled by air on the low temperature side, and of which the water content is separated by a water extractor 9, and the air bleed is introduced to a turbine 10. The thermal insulation inflated air bleed cools the primary liquid cold-heat exchanger 28. The air bleed on the high temperature side is cooled by the capacitor 8, and the air bleed is input in a turbine 3, and the cooled air is fed to a cabin. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air conditioning system for an aircraft, and more particularly, to an air conditioning system for air conditioning a cabin and cooling mounted devices such as electronic devices.
[0002]
[Prior art]
The air conditioning system for 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. Using (this is called ram air), (B) using a vapor cycle cooling system using a refrigerant, (C) using an air cycle cooling system, and performing cooling and heating using these combinations. I have. Older large aircraft and current turbine helicopters use a combination of (A) and (B) with a gas cycle system, and new jet aircraft use a combination of (A) and (C) with an air cycle system. (B) is combined with the cooling of the mounted equipment.
[0003]
Conventional air conditioning systems use a method of separating water under low pressure (hereinafter, referred to as an LPWS method) as an air cycle machine (hereinafter, referred to as an ACM). Alternatively, the APU (auxiliary power unit, which is bleeding from here when not flying, which is usually provided at the rear of the aircraft) has poor fuel economy, so a method of separating water under high pressure (hereinafter, HPWS) Method is called). In the HPWS system, the ACM outlet temperature can be lowered below the freezing point, so that the amount of bleed air used for obtaining the necessary cooling capacity can be smaller than that in the conventional LPWS system, so that the fuel efficiency of the engine or the APU is improved. Since the ACM outlet air is too cold to feed directly into the cabin, it mixes with some of the exhaust from the cabin returning through the recirculation line and is adjusted to a comfortable temperature before being fed to the cabin. Further, in the case where the cooling capacity is insufficient with the ACM alone for cooling mounted electronic devices and the like, a vapor cycle machine (referred to as a VCM) provided with a cooling device using a refrigerant or the like is provided for cooling. (For example, see Patent Document 1).
[0004]
FIG. 2 shows a circuit of a conventional HPWS type air conditioning system. In the air-conditioning system, a part of the air that has become high temperature and high pressure in the engine 102 is taken out by adjusting the pressure by a bleed control valve 102a, compressed by a compressor 101, and exchanging heat with ram air in a ram air heat exchanger 103. Cooled by. After the cooled bleed air is further cooled by heat exchange in the reheater 105, it is cooled by heat exchange with the low-temperature air passing through the low-temperature side passage in the condenser 106, so that the moisture in the bleed air is cooled below the open-air temperature. The water is separated in the water extractor 107 using centrifugal force. Then, the extracted air from which the water has been separated is used for cooling the extracted air before the separation of water in the reheater 105, and then expanded in the expansion turbine 108 to produce low-temperature air. The low-temperature air passes through the low-temperature side passage of the condenser 106 and is used for cooling the engine bleed air, and then passes through the liquid-cooled heat exchanger 112 and is sent out to the cabin of the aircraft. In the liquid-cooled heat exchanger 112, a coolant for cooling the electronic device 113 is circulated by a pump 114, and heat exchange is performed.
The expansion of the engine bleed air to rotate the expansion turbine 108 also acts as a driving force for the compressor 101 via the rotating shaft. Also, a valve 102b can be provided to perform temperature control by bypassing the bleed air from the engine 102 directly to the outlet of the expansion turbine 108.
[0005]
As described above, the air conditioning system compresses the high-temperature and high-pressure air obtained from the engine 102 with the compressor 101 of the ACM, removes the heat of the compression with the ram air heat exchanger 103, and then adiabatically expands with the expansion turbine 108. It is a system that uses the generated cooling air and is usually configured in units of air conditioning packs. One pack is equipped with one ACM and, if necessary, a plurality of packs. Then, the cooling air generated by the air conditioning system exits the air conditioning pack and is supplied through a pipe, and is used to cool the cabin and the electronic device 113. When the electronic device 113 is liquid-cooled, a liquid-cooled heat exchanger 112 is provided, and the cooling liquid is cooled via the liquid-cooled heat exchanger 112 downstream of the air conditioning system. In the dehumidification, the air to be dehumidified is cooled by the cooling air from the expansion turbine 108 via the condenser 106 to condense the moisture.
[0006]
According to the above-described HPWS system, by performing dehumidification of the engine bleed air upstream of the expansion turbine 108, the outlet temperature of the expansion turbine 108 can be lower than that of the LPWS system, and the air supplied to the cabin or the like can be cooled. By lowering the air temperature at the outlet of the expansion turbine 108, the bleed air flow required to achieve the same cooling capacity can be reduced, so that the fuel consumption required to operate the air conditioning system can be reduced. it can.
[0007]
However, in the air conditioning system of the HPWS system, moisture remaining in the bleed air after passing through the water extractor 107 freezes in the condenser 106 to block the bleed air passage, so that sufficiently low-temperature air can be supplied to the cabin or the like. May disappear. For this reason, for example, a part of the high-temperature engine bleed air is provided downstream of the expansion turbine 108 and a hot bar 109 as shown in FIG. The temperature of the low-temperature air is raised by heat exchange by passing a part of the air.
[0008]
[Patent Document 1]
JP-A-11-44463 (FIGS. 1-6, pages 2-4)
[0009]
[Problems to be solved by the invention]
The conventional air-conditioning system for aircraft is configured as described above, and cools by compressing and expanding the engine bleed air. The cooling capacity increases as the bleed air pressure introduced into the ACM increases. When sufficient pressure cannot be supplied, for example, when the engine 102 is in an idle state, there is a problem that the cooling capacity is reduced.
When the electronic device 25 and the like are cooled with a liquid refrigerant, the refrigerant is cooled through the cooling air generated by the ACM and the liquid cooling heat exchanger 112. At this time, the thermal energy obtained by the cooling air is merely a temperature. There is a problem that it only contributes to the rise.
In addition, in order to perform dehumidification, cryogenic air generated by the turbine 108 is used to cool the air to be dehumidified via the condenser 106. At this time, measures for preventing icing at the condenser 106 are added. There is a problem that must be.
[0010]
The present invention has been made in view of such circumstances, and does not reduce the cooling capacity even if the bleed pressure from the engine is reduced, and is a liquid-cooled heat exchanger for cooling mounted equipment. It is an object of the present invention to provide an air conditioning system for an aircraft that can effectively use heat exchange of the air and prevent icing in a condenser.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the aircraft air conditioning system of the present invention extracts a portion of high-temperature, high-pressure air from an aircraft engine, compresses the compressed air with a compressor provided coaxially with a turbine, An air conditioning system for aircraft that cools with a heat exchanger by ram air cool air and supplies low-temperature air by adiabatic expansion of turbines. Two turbines are connected in series, and mounted equipment is cooled by cooling air obtained by the first stage turbine. The liquid refrigerant to be cooled is cooled, and the cabin is air-conditioned by cooling air obtained by the second stage turbine.
[0012]
Further, the air conditioning system for an aircraft of the present invention is provided with two compressors, compresses the bleed air with the first-stage compressor, sends it to the primary heat exchanger, and then compresses the bleed air with the second-stage compressor to form the secondary heat exchanger. And compresses the bleed air in two stages.
[0013]
Further, the air conditioning system for an aircraft of the present invention is provided with a liquid-cooled heat exchanger for a liquid refrigerant for cooling mounted equipment upstream of a low-temperature side and a high-temperature side of a condenser for condensing moisture from bleed air.
[0014]
The aircraft air-conditioning system of the present invention is configured as described above, and two turbines are provided in series to cool a liquid refrigerant that cools mounted equipment with cooling air obtained by the first-stage turbine. The heat energy obtained at that time is recovered as the axial force of the second stage turbine, and the cabin is air-conditioned with the cooling air obtained there.
In addition, two compressors are provided, and the bleed air is compressed and pre-pressed by the first-stage compressor, sent to the primary heat exchanger, and then compressed by the second-stage compressor to increase the bleed pressure and then to the secondary heat exchanger. Feeding compresses the bleed air in two stages. Thereby, even if the pressure of the bleed air from the engine decreases, the cooling capacity does not decrease.
In addition, a primary liquid-cooled heat exchanger that cools mounted equipment is installed upstream of the low-temperature side of the condenser, and the temperature of the cryogenic air generated by the first-stage turbine rises before flowing into the condenser, No freezing on capacitors. In addition, a secondary liquid cooling heat exchanger that cools the mounted equipment is installed upstream of the high temperature side of the condenser to cool the bleed air and send it to the condenser.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
One embodiment of an air conditioning system for an aircraft of the present invention will be described with reference to FIG.
FIG. 1 is a diagram showing an air conditioning circuit of the air conditioning system for an aircraft of the present invention. The air-conditioning system for aircraft according to the present invention includes a compressor 2 that takes in and extracts high-temperature and high-pressure bleed air from an engine 1 and introduces it into a primary heat exchanger 4, a primary heat exchanger 4 and a secondary heat exchanger provided in a ram air circuit. An exchange 6, a compressor 5 for compressing air heat exchanged in the primary heat exchanger 4 and introducing the compressed air into the secondary heat exchanger 6, and a pump 26 provided in a liquid cooling line 27 for cooling the electronic equipment 25. The liquid-cooled heat exchanger 28, the secondary liquid-cooled heat exchanger 29, and the air from the secondary heat exchanger 6 are cooled by the secondary liquid-cooled heat exchanger 29 and introduced into the high-temperature side circuit. A condenser 8 for introducing the air cooled in the liquid-cooled heat exchanger 28 to the low-temperature side circuit and cooling the air in the high-temperature side circuit to condense water, a water extractor 9 for removing the condensed water by centrifugation, Pressurized air And a turbine 10 for adiabatic expansion, and a low-temperature air supply turbine 3 which introduces cold air by adiabatic expansion cabin from the capacitor 8.
[0016]
The difference between the aircraft air conditioning system and the conventional system is that, in the conventional system, as shown in FIG. In this system, an “energy recovery boost air cycle system” is configured, which includes two turbines 10 and 3 and a flow path between them. A primary liquid-cooled heat exchanger 28 and a condenser 8 are provided, cooling is performed, and heat energy obtained at this time is recovered as an axial force of the second stage turbine 3, and cooling air of the preceding stage is introduced into the second stage turbine 3, The adiabatic expanded air is supplied to a cabin or the like.
The power of the second-stage turbine 3 is used as the power of the first-stage compressor 2 mounted coaxially, and high-temperature and high-pressure bleed air is efficiently taken in from the engine 1.
Further, in the conventional system, as shown in FIG. 2, the engine bleed air from the engine 102 is compressed by only the single-stage compressor 101 and introduced into the ram air heat exchanger 103. Compressed by the compressor 2 and the compressor 5 and introduced into the primary heat exchanger 4 and the secondary heat exchanger 6, the cooling capacity is improved even when the engine bleed pressure is reduced.
Further, as shown in FIG. 2, the conventional system introduces the output of the expansion turbine 108 to the condenser 106 and is provided with a hot bar 109 and the like for preventing icing. After being introduced into the primary liquid cooling heat exchanger 28 for cooling the electronic equipment 25, it is sent to the condenser 8. Therefore, the condenser 8 does not need any countermeasures against icing, and uses the cold heat for cooling the electronic device 25.
In the conventional system, the reheater 105 is provided for the effective use of the cold heat. However, in the present system, the secondary liquid-cooled heat exchanger 29 is provided downstream of the primary liquid-cooled heat exchanger 28 for cooling the electronic device 25. It does not require the reheater 105.
[0017]
Next, the operation of the air conditioning system for an aircraft will be described. High-temperature, high-pressure air from the engine 1 is taken into the first-stage compressor 2 via a bleed control valve 1a, compressed, and introduced into the primary heat exchanger 4. Air outside the machine is drawn into the ram air circuit by a fan (not shown) or an ejector (not shown) provided coaxially with the second stage compressor 5. The primary heat exchanger 4 and the secondary heat exchanger 6 are cooled by the ram air. The air compressed by the first-stage compressor 2 and heat-exchanged by the primary heat exchanger 4 is compressed by the second-stage compressor 5 and introduced into the secondary heat exchanger 6 where heat is exchanged. The air that has exited the secondary heat exchanger 6 is introduced into the high-temperature circuit of the secondary liquid-cooled heat exchanger 29, cooled, and introduced into the high-temperature circuit of the condenser 8. In the condenser 8, the air cooled by the adiabatic expansion of the turbine 10 is introduced into the low-temperature side circuit via the primary liquid-cooled heat exchanger 28 to cool the air in the high-temperature side circuit, and most of the moisture in the air is condensed. Then, they are separated and removed by centrifugation in the water extractor 9. The air from which the moisture has been removed is directly introduced into the turbine 10. The introduced air is adiabatically expanded in the turbine 10, cools the primary liquid-cooled heat exchanger 28 and exchanges heat, passes through the condenser 8, and uses the heat energy obtained at this time as the axial force of the second-stage turbine 3. It is collected and introduced into the second stage turbine 3. The introduced air is adiabatically expanded by the turbine 3 and supplied to the cabin side. At this time, since the air temperature is 0 ° C or less, a mixing chamber and a recirculation circuit are provided in the middle instead of directly supplying to the cabin, and a part of the warm air in the cabin is recirculated by the recirculation fan and the halves to adjust the amount of recirculated air. Is controlled and removed, and both airs are mixed in a mixing chamber, adjusted to a comfortable temperature, and then introduced into the cabin.
[0018]
This air conditioning system includes two turbines 10 and 3, and cools the primary liquid-cooled heat exchanger 28 for cooling the electronic device 25 by adiabatic expansion of the first-stage turbine 10, and reduces the remaining thermal energy to two stages. The air is recovered as the axial force of the eye turbine 3 and the adiabatic expanded air is supplied to a cabin or the like. In this system, the power of the second-stage turbine 3 is used as the power of the first-stage compressor 2 mounted coaxially, and the energy is effectively recovered and the cooling is performed efficiently.
Further, even when the two-stage compressor 2 and the compressor 5 are provided and the bleed pressure from the engine 1 is low, for example, when the engine 1 is in an idle state while parked, the cooling capacity does not decrease. In addition, a pressure drop at the air conditioning system inlet due to the increase in the flow rate is not caused.
[0019]
In the above embodiment, the primary heat exchanger 4 is provided between the compressor 2 and the compressor 5, but the compressor 2 may be arranged downstream of the primary heat exchanger 4 in series with the compressor 5.
[0020]
【The invention's effect】
The aircraft air-conditioning system of the present invention is configured as described above, is provided with two turbines, adiabatically expands the bleed air with the first-stage turbine, and cools the liquid-cooled heat exchanger for cooling the mounted equipment. Can be recovered as the axial force of the second stage turbine, increasing the pressure ratio of the boost ACM compressor. As a result, at the same supply bleed pressure, the cooling capacity increases compared to the conventional case. I do. And the cabin can be air-conditioned with the cooling air obtained there.
In addition, two compressors are provided, and the bleed air can be compressed and pre-pressed by the first-stage compressor and the bleed pressure can be increased by compressing the bleed air by the second-stage compressor. Even if it becomes low, it can be operated without lowering the cooling capacity.
In addition, since a primary liquid-cooled heat exchanger that cools mounted equipment is installed upstream of the cold side of the condenser, the temperature of the cryogenic air generated by the first stage turbine is reduced before flowing into the condenser. Since it rises, there is no icing at the condenser and no anti-icing measures need to be taken.
In addition, a secondary liquid cooling heat exchanger is installed upstream of the hot side of the condenser, and the bleed air can be cooled and sent to the condenser, so the commonly used reheater can be eliminated from the system and the system can be reduced in size and size. Weight reduction becomes possible.
[Brief description of the drawings]
FIG. 1 is a diagram showing one embodiment of an aircraft air conditioning system of the present invention.
FIG. 2 is a diagram showing an electronic device cooling circuit of a conventional aircraft air conditioning system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 1a Valve 2 Compressor 3, 10 Turbine 4 Primary heat exchanger 5 Compressor 6 Secondary heat exchanger 8 Condenser 9 Water extractor 25 Electronic equipment 26 Pump 27 Liquid cooling line 28 Primary liquid cooling heat exchanger 29 Secondary liquid cooling heat exchange vessel

Claims (3)

A portion of the high-temperature, high-pressure air of the aircraft engine is extracted, compressed by a compressor provided coaxially with the turbine, cooled by a heat exchanger using ram air cool air outside the aircraft, and cooled by the adiabatic expansion of the turbine. An aircraft air-conditioning system for supplying, in which two turbines are provided in series to cool a liquid refrigerant for cooling onboard equipment with cooling air obtained by a first-stage turbine, and to be obtained by a second-stage turbine. An air conditioning system for an aircraft, wherein the cabin is air-conditioned with cooled air. Providing two compressors, compressing the bleed air with the first stage compressor and sending it to the primary heat exchanger, then compressing it with the second stage compressor and sending it to the secondary heat exchanger to compress the bleed air in two stages The aircraft air conditioning system according to claim 1, wherein: 2. An air conditioning system for an aircraft according to claim 1, further comprising a liquid-cooled heat exchanger for a liquid refrigerant for cooling the mounted equipment, provided upstream of the low-temperature side and the high-temperature side of the condenser for condensing moisture in the bleed air. .

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