Environmental control systems for civil aircraft

Abstract

An environmental control system for a civil aircraft can ensure the lift-to-drag ratio of the aircraft, reduce the bleed air volume and overflow loss of ram air, and reduce the loss of fuel. The environmental control system includes an air circulation refrigeration subsystem with a refrigeration heat exchanger, an air preparation subsystem with an air preparation heat exchanger, an auxiliary cooling subsystem with an auxiliary cooling heat exchanger, and a ram air flow channel with a ram air inlet and a ram air outlet, the ram air flow channel includes a first ram air branch flow channel and a second ram air branch flow channel connected in parallel, the auxiliary cooling heat exchanger and the refrigeration heat exchanger are arranged in the first ram air branch flow channel, and the air preparation heat exchanger is arranged in the second ram air branch flow channel.

Description

Technical Field

[0001] The invention relates to an environmental control system for a civil aircraft. Background Art

[0002] In modern civil aircraft, as the requirements for safety and comfort become increasingly stringent, especially for wide-body aircraft, the cooling demand is affected by the number of passengers, heat-generating electronic equipment, the number of meals, and fuel protection. Aircraft usually need to use refrigeration temperature control systems, auxiliary cooling systems, and air preparation systems to provide energy for cooling the entire aircraft.

[0003] In traditional wide-body aircraft, the refrigeration temperature control system, auxiliary cooling system, and air preparation system are generally designed, installed, and controlled independently. For example, the refrigeration temperature control system uses independent engine bleed air as the hot side and independent ram air as the cold side. The main equipment is installed in the front wing fairing area, with the air source system upstream and the ventilation system downstream; the auxiliary cooling system uses an independent refrigerant as the loop and an independent ram air as the cold side. The main equipment is installed in the rear wing fairing area, with the liquid storage tank upstream and the kitchen or electronic equipment compartment downstream; the air preparation system uses independent engine bleed air as the hot side and independent ram air as the cold side. The main equipment is installed in the front wing fairing area, with the air source system upstream and the inerting system downstream.

[0004] Take a certain model as an example. If the refrigeration temperature control system, auxiliary cooling system, and air preparation system are designed according to the traditional method, each system will be designed independently. This requires:

[0005] a) Two sets of ram air flow channels serving the two-stage heat exchangers of the refrigeration temperature control system, each set including complete ram air inlet, inlet damper, inlet damper actuator, distribution pipeline, muffler, fan, valve, ram air outlet, outlet damper, outlet damper actuator;

[0006] b) Two sets of ram air flow passages serving the auxiliary cooling system condensers, each set including complete ram air inlet, inlet damper, inlet damper actuator, distribution piping, silencer, fan, valve, ram air outlet, outlet damper, outlet damper actuator;

[0007] c) two sets of ram air flow passages serving the air preparation system heat exchangers, each set containing a complete ram air inlet, inlet damper, inlet damper actuator, distribution piping, silencer, fan, valve, ram air outlet, outlet damper, and outlet damper actuator;

[0008] Such an environmental control system that has not been integrated has 6 skin inlets, 6 skin outlets, and 6 sets of ram air internal flow pipes. Summary of the invention

[0009] Technical problem to be solved by the invention

[0010] The advantage of this form of system architecture is that each system works independently of each other, without interference, and has low control difficulty. However, the negative impact is that the three systems use independent ram air cooling, which requires openings in multiple places on the aircraft skin. The openings on the lifting surface of the skin lead to a decrease in the aircraft's lift-to-drag ratio; the three systems use independent ram air bleed cooling, but the ram air is discharged out of the aircraft before its cooling capacity is fully utilized, wasting ram air bleed, and the bleed air volume leads to increased flight resistance; the three systems use independent ram air cooling, and fans are used to extract ambient air for cooling when on the ground. The aircraft needs to carry more weight during flight, and the weight leads to increased fuel consumption.

[0011] In view of the above, an object of the present invention is to provide an environmental control system for a civil aircraft, which can ensure the lift-to-drag ratio of the aircraft, reduce the bleed air volume and overflow loss of ram air, and reduce fuel consumption.

[0012] Technical solutions adopted to solve technical problems

[0013] The environmental control system of a civil aircraft according to a first aspect of the present invention comprises an air cycle refrigeration subsystem having a refrigeration heat exchanger, an air preparation subsystem having an air preparation heat exchanger, an auxiliary cooling subsystem having an auxiliary cooling heat exchanger, and a ram air flow passage having a ram air inlet and a ram air outlet, wherein:

[0014] The ram air flow channel includes a first ram air branch flow channel and a second ram air branch flow channel connected in parallel,

[0015] The auxiliary cooling heat exchanger and the cooling heat exchanger are arranged in the first ram air branch flow channel, and the air preparation heat exchanger is arranged in the second ram air branch flow channel.

[0016] According to the environmental control system of a civil aircraft described in the first viewpoint, by bifurcating a ram air flow channel into a first ram air branch flow channel and a second ram air branch flow channel connected in parallel, the ram air overflowing from one branch flow channel can flow into another branch flow channel without overflowing, thereby reducing the aircraft ram air bleed volume and overflow loss. In addition, by arranging the refrigeration heat exchanger and the auxiliary cooling heat exchanger in the first ram air branch flow channel in a manner connected in series with the ram air, and arranging the air preparation heat exchanger in the second ram air branch flow channel, the cooling energy of the ram air can be released more fully. Moreover, compared with the prior art, since only one ram air flow channel is provided, only one inlet and one opening need to be opened on the aircraft skin, which can avoid the reduction of the aircraft lift-drag ratio due to the opening of the skin lifting surface.

[0017] On the basis of the environmental control system described in the first viewpoint, in the environmental control system of a civil aircraft of the second viewpoint, preferably, a water ejector is provided at a portion of the first ram air branch flow channel upstream of the auxiliary cooling heat exchanger and the refrigeration heat exchanger, and the water ejector ejects water into the first ram air branch flow channel.

[0018] According to the environmental control system of a civil aircraft described in the second aspect, a water ejector is provided in the first ram air branch flow passage to eject water toward the auxiliary cooling heat exchanger and the refrigeration heat exchanger in the first ram air branch flow passage, thereby improving the heat exchange efficiency of the heat exchanger.

[0019] Based on the environmental control system described in the first aspect, in the environmental control system of a civil aircraft of the third aspect, preferably, a ram air flow control valve is provided in the second ram air branch flow channel, and the ram air flow control valve adjusts the flow rate of the ram air flowing in the second ram air branch flow channel.

[0020] According to the environmental control system of the civil aircraft described in the third aspect, when the flow rate of the ram air in the second ram air branch flow channel is too large, the amount of cooling heat exchange can be reduced by reducing the opening of the ram air flow rate control valve.

[0021] In the environmental control system according to the first aspect, in the environmental control system for a civil aircraft according to the fourth aspect, preferably,

[0022] The refrigeration heat exchanger comprises a first refrigeration heat exchanger located upstream and a second refrigeration heat exchanger located downstream which are connected in series.

[0023] The first refrigeration heat exchanger is connected to an air source system for supplying bleed air located upstream, and the second refrigeration heat exchanger is connected to a ventilation system located downstream.

[0024] The first refrigeration heat exchanger is connected to a first bypass pipeline that bypasses the second refrigeration heat exchanger and is directly connected to the ventilation system.

[0025] According to the environmental control system of a civil aircraft described in the fourth viewpoint, on the basis of being provided with a first bypass duct, by adjusting the flow rate of bleed air flowing through the first bypass duct, the cooling and mixing flow ratio of the bleed air can be changed, which is beneficial to the adjustment of the bleed air temperature.

[0026] Based on the environmental control system described in the fourth aspect, in the environmental control system for a civil aircraft described in the fifth aspect, preferably,

[0027] It also includes an integrated controller, which adjusts the flow rate of the ram air flowing in the first ram air branch flow channel and the flow rate of the bleed air flowing in the first bypass duct according to the difference between the temperature of the bleed air at the downstream outlet of the air circulation refrigeration subsystem and the target refrigeration temperature, so that the temperature of the bleed air at the downstream outlet of the air circulation refrigeration subsystem reaches the target refrigeration temperature.

[0028] According to the fifth aspect, the environmental control system of the civil aircraft can make the temperature of the bleed air supplied to the ventilation system of the air cycle refrigeration subsystem reach the specified target refrigeration temperature by simultaneously adjusting the flow rate of the ram air flowing through the refrigeration heat exchanger and the mixing flow rate ratio of the bleed air flowing in the air cycle refrigeration subsystem. Thus, the bleed air temperature requirement of the air cycle refrigeration subsystem, which consumes the most energy in the environmental control system, can be preferentially met.

[0029] Based on the environmental control system described in the fourth aspect, in the environmental control system for a civil aircraft described in the sixth aspect, preferably,

[0030] The air preparation heat exchanger includes a first air preparation heat exchanger located upstream and a second air preparation heat exchanger located downstream, which are connected in series.

[0031] The first air preparation heat exchanger is connected to an air source system for supplying bleed air located upstream, and the second air preparation heat exchanger is connected to an inerting system located downstream.

[0032] The first air preparation heat exchanger is connected to a second bypass line that bypasses the second air preparation heat exchanger and is directly connected to the inerting system.

[0033] According to the environmental control system of a civil aircraft described in the fourth viewpoint, on the basis of being provided with a second bypass duct, by adjusting the flow rate of bleed air flowing through the second bypass duct, the cooling and mixing flow ratio of the bleed air can be changed, which is beneficial to the adjustment of the bleed air temperature.

[0034] Based on the environmental control system described in the sixth aspect, in the environmental control system for a civil aircraft described in the seventh aspect, preferably,

[0035] The system further includes an integrated controller, which adjusts the flow rate of the ram air flowing in the first ram air branch flow channel and the flow rate of the bleed air flowing in the first bypass line according to the difference between the temperature of the bleed air at the downstream outlet of the air cycle refrigeration subsystem and the target refrigeration temperature, so that the temperature of the bleed air at the downstream outlet of the air cycle refrigeration subsystem reaches the target refrigeration temperature.

[0036] When the temperature of the bleed air at the downstream outlet of the air circulation refrigeration subsystem reaches the target refrigeration temperature, the integrated controller adjusts the flow rate of the bleed air flowing in the second bypass duct according to the difference between the temperature of the bleed air at the downstream outlet of the air preparation subsystem and the target air preparation temperature, so that the temperature of the bleed air at the downstream outlet of the air preparation subsystem reaches the target air preparation temperature.

[0037] According to the environmental control system of the civil aircraft described in the seventh viewpoint, considering that the subsystem with the largest energy consumption demand in the environmental control system is the air circulation refrigeration subsystem, therefore, in order to make full use of the cooling energy of the ram air as much as possible, the temperature of the bleed air flowing in the air circulation refrigeration subsystem is first adjusted by the integrated controller so that the temperature of the bleed air at the downstream outlet reaches the target refrigeration temperature. Then, the residual cooling energy of the ram air is fully utilized, and the temperature of the bleed air flowing in the air preparation subsystem is adjusted by the integrated controller so that the temperature of the bleed air at the downstream outlet reaches the target air preparation temperature. In this way, the energy consumption demand of the air preparation subsystem can be met while the cooling energy consumption demand of the air circulation refrigeration subsystem with the largest energy consumption is met, and the closed-loop control of the temperature can be achieved while the original cooling capacity and the upstream and downstream system interfaces remain unchanged.

[0038] Based on the environmental control system described in the fourth aspect, in the environmental control system for a civil aircraft described in the eighth aspect, preferably,

[0039] The auxiliary cooling subsystem includes a refrigerant circuit connected to an evaporator, a liquid storage tank, the auxiliary cooling heat exchanger and a compressor, and the refrigerant circuit is used for refrigerant circulation.

[0040] The refrigerant circuit is formed with a third bypass line that bypasses the auxiliary cooling heat exchanger.

[0041] According to the environmental control system of a civil aircraft described in the eighth viewpoint, on the basis of being provided with a third bypass line, by adjusting the flow rate of the refrigerant flowing through the third bypass line, the cooling and mixing flow ratio of the refrigerant can be changed, which is beneficial to the regulation of the refrigerant temperature.

[0042] Based on the environmental control system described in the eighth aspect, in the environmental control system for a civil aircraft described in the ninth aspect, preferably,

[0043] The system further includes an integrated controller, which adjusts the flow rate of the ram air flowing in the first ram air branch flow channel and the flow rate of the bleed air flowing in the first bypass line according to the difference between the temperature of the bleed air at the downstream outlet of the air cycle refrigeration subsystem and the target refrigeration temperature, so that the temperature of the bleed air at the downstream outlet of the air cycle refrigeration subsystem reaches the target refrigeration temperature.

[0044] When the temperature of the bleed air at the downstream outlet of the air circulation refrigeration subsystem reaches the target refrigeration temperature, the integrated controller adjusts the flow rate of the refrigerant flowing in the third bypass line and the speed of the compressor according to the difference between the temperature of the refrigerant in the liquid storage tank of the auxiliary cooling subsystem and the target auxiliary cooling temperature, so that the temperature of the refrigerant in the liquid storage tank of the auxiliary cooling subsystem reaches the target auxiliary cooling temperature.

[0045] According to the environmental control system of the civil aircraft described in the ninth viewpoint, considering that the subsystem with the largest energy consumption demand in the environmental control system is the air circulation refrigeration subsystem, therefore, in order to make full use of the cooling energy of the ram air, the temperature of the bleed air flowing in the air circulation refrigeration subsystem is first adjusted by the integrated controller so that the temperature of the bleed air at the downstream outlet reaches the target refrigeration temperature. Then, the temperature of the refrigerant flowing in the auxiliary cooling subsystem is adjusted by the integrated controller so that the temperature of the refrigerant in the liquid storage tank reaches the target auxiliary cooling temperature. In this way, the energy consumption demand of the auxiliary cooling subsystem can be met while the refrigeration energy consumption demand of the air circulation refrigeration subsystem with the largest energy consumption is met, and the closed-loop control of the temperature can be achieved while the original refrigeration capacity and the upstream and downstream system interfaces remain unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of an environmental control system for a civil aircraft according to one embodiment of the present invention.

[0047] Figure 2 Shows Figure 1 Schematic diagram of the air circulation refrigeration subsystem in the environmental control system.

[0048] Figure 3 Shows Figure 1 Schematic diagram of the air preparation subsystem in an environmental control system. DETAILED DESCRIPTION

[0049] Next, the general structure of the environmental control system of a civil aircraft according to one embodiment of the present invention will be described with reference to the accompanying drawings.

[0050] Figure 1FIG. 1 shows an architecture diagram of an environmental control system (hereinafter referred to as an environmental control system) S for a civil aircraft according to an embodiment of the present invention. Figure 1 As shown, the environmental control system S is an integrated environmental control system, including an air circulation refrigeration subsystem SS1, an air preparation subsystem SS2, an auxiliary cooling subsystem SS3, a ram air flow channel AC and an integrated controller IC. Among them, the air circulation refrigeration subsystem SS1, the air preparation subsystem SS2 and the auxiliary cooling subsystem SS3 constitute the hot side of the environmental control system S, and the ram air flow channel AC constitutes the cold side of the environmental control system S. The upstream inlet of the air circulation refrigeration subsystem SS1 is connected to the air source system A that supplies high-temperature and high-pressure bleed air, and the downstream outlet is connected to the ventilation system V that supplies conditioned air to the cabin. The air preparation subsystem SS2 is connected to the air circulation refrigeration subsystem in parallel with the air source system A, the upstream inlet is connected to the air source system A, and the downstream outlet is connected to the inerting system B. The auxiliary cooling subsystem SS3 is a subsystem for adjusting the temperature of the kitchen or electronic equipment compartment K, and it has a refrigerant circuit for refrigerant circulation. The integrated controller IC is a controller for closed-loop control of the temperature of the bleed air or refrigerant in the air circulation refrigeration subsystem SS1, the air preparation subsystem SS2, and the auxiliary cooling subsystem SS3. The details of the integrated controller IC will be described in detail later.

[0051] like Figure 1 As shown, the air circulation refrigeration subsystem SS1 and the air preparation subsystem SS2 are connected in parallel with respect to the air source system A. Specifically, the air circulation refrigeration subsystem SS1 (to be precise, the first refrigeration heat exchanger 11 described later) is connected to the air source system A through the first pipeline P1, and the air preparation subsystem SS2 is connected to the air source system A through the second pipeline P2. In addition, a first bleed air inlet regulating valve PV1 is provided in the first pipeline P1, and the amount of bleed air supplied to the air circulation refrigeration subsystem SS1 is adjusted by adjusting the opening of the first bleed air inlet regulating valve PV1. A second bleed air inlet regulating valve PV2 is provided in the second pipeline P2, and the amount of bleed air supplied to the air preparation subsystem SS2 is adjusted by adjusting the opening of the second bleed air inlet regulating valve PV2.

[0052] For ease of understanding, Figure 2 A schematic diagram of the air circulation refrigeration subsystem SS1 in the environmental control system S of this embodiment is shown separately. Figure 2As shown, in this embodiment, the air circulation refrigeration subsystem SS1 adopts a three-wheel boost type high-pressure dehydration air circulation refrigeration system, including a first refrigeration heat exchanger 11 as a primary refrigeration heat exchanger, a refrigeration compressor 12, a second refrigeration heat exchanger 13 as a secondary refrigeration heat exchanger, a regenerator 14, a refrigeration condenser 15, a water separator 16, and a refrigeration turbine 17. The first refrigeration heat exchanger 11 is connected to the air source system A through a first pipeline P1, and the refrigeration condenser 15 is connected to the ventilation system V through a third pipeline P3. In addition, in this embodiment, a first temperature sensor TS1 for detecting the temperature of the bleed air at the downstream outlet of the air circulation refrigeration subsystem SS1 is provided in the third pipeline P3. In addition, one end of the first bypass line BP1 is connected to the first refrigeration heat exchanger 11, and the other end of the first bypass line BP1 bypasses the refrigeration compressor 12, the second refrigeration heat exchanger 13, the regenerator 14, the water separator 16, and the refrigeration turbine 17 and is connected to the upstream side of the refrigeration condenser 15. A first bypass valve BV1 is provided in the middle of the first bypass line BP1, and the first bypass valve BV1 adjusts the amount of bleed air flowing in the first bypass line BP1.

[0053] Next, combine Figure 1 and Figure 2 , the flow condition of the bleed air in the air cycle refrigeration subsystem SS1 of the present embodiment is described.

[0054] First, a portion of the high-temperature and high-pressure bleed air sent from the air source system A flows to the first pipeline P1. This portion of bleed air flows into the first cooling heat exchanger 11 via the first pipeline P1 and the first bleed air inlet regulating valve PV1 set in the middle of the first pipeline P1, and performs heat exchange with the ram air flowing in the first ram air branch flow channel SAC1 of the ram air flow channel AC described later in the first cooling heat exchanger 11. Then, the bleed air after the heat exchange flows into the cooling compressor 12 and is compressed, and then flows into the second cooling heat exchanger 13 and performs heat exchange with the ram air flowing in the first ram air branch flow channel SAC1. Then, the bleed air that has completed the heat exchange in the second cooling heat exchanger 13 flows into the regenerator 14 and further flows into the cooling condenser 15 to be cooled and liquid water is precipitated, thereby forming a gas-liquid two-phase bleed air. Then, the bleed air in the gas-liquid two-phase state flows into the water separator 16, and the free water is removed by the water separator 16. Then, the bleed air in a dry state after the free water is removed flows into the refrigeration turbine 17 for expansion and cooling. Finally, the bleed air expanded and cooled in the refrigeration turbine 17 is supplied to the ventilation system V via the third pipe P3. When the bleed air flows in the third pipe P3, the first temperature sensor TS1 detects the temperature of the bleed air. In addition, when the closed-loop control of the temperature of the bleed air in the air circulation refrigeration subsystem SS1 described later is performed, the amount of bleed air flowing in the first bypass pipe BP1 is adjusted by adjusting the opening of the first bypass valve BV1, thereby adjusting the mixing flow ratio of the bleed air flowing in the air circulation refrigeration subsystem SS1.

[0055] For ease of understanding, Figure 3 A schematic diagram of the air preparation subsystem SS2 in the environmental control system S of this embodiment is shown separately. Figure 3As shown, the air preparation subsystem SS2 includes a first air preparation heat exchanger 21 as a primary air preparation heat exchanger, a three-way valve 22, and a second air preparation heat exchanger 23 as a secondary air preparation heat exchanger. The first air preparation heat exchanger 21 is connected to the air source system A through the second pipeline P2, the first air preparation heat exchanger 21, the three-way valve 22 and the second air preparation heat exchanger 23 are connected in series, and the second air preparation heat exchanger 23 is connected to the inerting system B through the fourth pipeline P4. Specifically, the first air preparation heat exchanger 21 is connected to the first port of the three-way valve 22, and the second air preparation heat exchanger 23 is connected to the second port of the three-way valve 22. In addition, one end of a branch pipeline BAP is connected between the second bleed air inlet regulating valve PV2 of the second pipeline P2 and the first air preparation heat exchanger 21, and the other end of the branch pipe BAP is connected to the pipeline between the second port of the three-way valve 22 and the second air preparation heat exchanger 23. In the branch pipe BAP, the branch pipe valve BAV, the air preparation turbine 24, and the air preparation compressor 25 with a shaft fan are connected in sequence from one end to the other end, and the third port of the three-way valve 22 is connected to the pipeline between the air preparation turbine 24 and the air preparation compressor 25. In addition, one end of the second bypass pipe BP2 is connected in the middle of the pipeline between the first air preparation heat exchanger 21 and the second air preparation heat exchanger 23, and the other end of the second bypass pipe BP2 is connected to the fourth pipe P4. In other words, the second bypass pipe BP2 is configured to bypass the second air preparation heat exchanger 23. In addition, a second bypass valve BV2 is provided in the second bypass pipe BP2, and the second bypass valve BV2 adjusts the amount of bleed air flowing in the second bypass pipe BP2. In addition, in the present embodiment, a second temperature sensor TS2 is provided in the fourth pipe P4 to detect the temperature of the bleed air at the downstream outlet of the air preparation subsystem SS2.

[0056] Next, combine Figure 1 and Figure 3 , the flow condition of the bleed air in the air preparation subsystem SS2 of the present embodiment will be described.

[0057] First, another part of the high-temperature and high-pressure bleed air sent from the air source system A flows to the second pipeline P2. This part of the bleed air flows into the first air preparation heat exchanger 21 via the second pipeline P2 and the second bleed air inlet regulating valve PV2 set in the middle of the second pipeline P2, and performs heat exchange with the ram air flowing in the second ram air branch flow channel SAC2 of the ram air flow channel AC described later in the first air preparation heat exchanger 21. Then, the bleed air that has completed the heat exchange in the first air preparation heat exchanger 21 flows into the second air preparation heat exchanger 23 via the three-way valve 22. It should be noted that when the pressure of the bleed air in the second pipeline P2 is sufficient, the third port of the three-way valve 22 and the branch pipe valve BAV are closed. The bleed air flowing into the second air preparation heat exchanger 23 performs heat exchange again with the ram air flowing in the second ram air branch flow channel SAC2 in the second air preparation heat exchanger 23. Then, the bleed air that has completed the heat exchange in the second air preparation heat exchanger 23 is supplied to the inerting system B via the fourth pipe P4. The second temperature sensor TS2 provided in the middle of the fourth pipe P4 detects the temperature of the bleed air flowing in the fourth pipe P4. On the other hand, when the pressure of the bleed air flowing in the second pipe P2 is insufficient, the branch pipe valve BAV provided in the branch pipe BAP is opened, and a small part of the bleed air flowing in the second pipe P2 is diverted to the branch pipe BAP, and most of the bleed air still flows into the first air preparation heat exchanger 21. The small part of the bleed air that flows into the branch pipe BAP further flows into the air preparation turbine 24 and expands to do work, thereby driving the shaft fan of the air preparation compressor 25 located downstream of the air preparation turbine 24 to rotate. At the same time, the third port of the three-way valve 22 is opened and the second port is closed, and the bleed air that has completed the heat exchange in the first air preparation heat exchanger 21 flows into the air preparation compressor 25 and merges with the small part of the bleed air from the air preparation turbine 24 and is pressurized. Then, the bleed air that has completed supercharging in the air preparation compressor 25 flows from the air preparation compressor 25 into the second air preparation heat exchanger 23, and performs heat exchange again with the ram air flowing in the second ram air branch flow channel SAC2 in the second air preparation heat exchanger 23. Finally, the bleed air that has completed heat exchange in the second air preparation heat exchanger 23 is supplied to the inerting system B via the fourth pipeline P4. When the bleed air flows in the fourth pipeline P4, the second temperature sensor TS2 detects the temperature of the bleed air. In addition, when performing closed-loop control of the temperature of the bleed air in the air preparation subsystem SS2 described later, the amount of bleed air flowing in the second bypass pipeline BP2 is adjusted by adjusting the opening of the second bypass valve BV2, thereby adjusting the mixing flow ratio of the bleed air flowing in the air preparation subsystem SS2.

[0058] Next, we will refer to Figure 1, the structure of the auxiliary cooling subsystem SS3 in the environmental control system S of the civil aircraft according to the present embodiment will be described.

[0059] like Figure 1 As shown, the auxiliary cooling subsystem SS3 has a refrigerant circuit RC1, and the refrigerant circuit RC1 is composed of an evaporator 31, a liquid storage tank 32, an auxiliary cooling heat exchanger 33, and an auxiliary cooling compressor 34 connected by refrigerant pipes. The liquid storage tank 32 stores a liquid refrigerant. In addition, a third bypass line BP3 that bypasses the auxiliary cooling heat exchanger 33 is formed in the refrigerant circuit RC1, and the third bypass line BP3 is provided with a third bypass valve BV3 that adjusts the amount of refrigeration flowing in the third bypass line BP3. In addition, in the present embodiment, a third temperature sensor TS3 is provided in the refrigerant line on the side of the inlet of the liquid storage tank 32 of the refrigerant circuit RC1, and the third temperature sensor TS detects the temperature of the refrigerant that is about to flow in from the inlet of the liquid storage tank 32. However, the setting position of the third temperature sensor TS3 is not limited to this, and it can also be set inside the liquid storage tank 32 to detect the temperature of the refrigerant in the liquid storage tank 32. It should be noted that ethylene glycol is used as the refrigerant in the present embodiment.

[0060] Then, still combine Figure 1 , the flow condition of the refrigerant in the auxiliary cooling subsystem SS3 of this embodiment is described.

[0061] First, under the action of the auxiliary cooling compressor 34, the liquid refrigerant stored in the liquid storage tank 32 flows out from the outlet of the liquid storage tank 32. Then, the liquid refrigerant flowing out from the outlet of the liquid storage tank 32 exchanges heat with the heat medium of the kitchen or electronic equipment compartment K in the evaporator 31 and evaporates, thereby becoming a gaseous refrigerant. Then, the gaseous refrigerant that has completed the heat exchange in the evaporator 31 flows into the auxiliary cooling compressor 34 and is compressed, and then flows into the auxiliary cooling heat exchanger 33. Then, the gaseous refrigerant flowing into the auxiliary cooling heat exchanger 33 exchanges heat with the ram air flowing in the first ram air branch flow channel SAC1 and condenses, thereby forming a liquid (or gas-liquid two-phase) refrigerant. Finally, the liquid (or gas-liquid two-phase) refrigerant returns to the liquid storage tank 32 through the inlet of the liquid storage tank 32. When the refrigerant is about to flow into the liquid storage tank 32 or has already flowed into the liquid storage tank 32, the third temperature sensor TS3 detects the temperature of the refrigerant that is about to flow into the liquid storage tank 32 or has already been stored in the liquid storage tank 32. In addition, when the closed-loop control of the temperature of the refrigerant in the auxiliary cooling subsystem SS3 described later is performed, the amount of refrigerant flowing in the third bypass pipe BP3 is adjusted by adjusting the opening of the third bypass valve BV3, thereby adjusting the mixing flow ratio of the refrigerant flowing in the air preparation subsystem SS3.

[0062] The air circulation refrigeration subsystem SS1, the air preparation subsystem SS2, and the auxiliary cooling subsystem SS3 constituting the hot side (hot path) of the environmental control system S of this embodiment have been described above. Figure 1 Next, the ram air flow passage AC constituting the cold side (cold path) of the environmental control system S according to the present embodiment will be described.

[0063] like Figure 1As shown, the ram air flow channel AC is a channel that uses the pressure difference between the inside and outside of the aircraft to introduce the air outside the aircraft as ram air and make it flow inside, including an air inlet 4, an inlet-side ram air flow channel AC0, a first ram air branch flow channel SAC1, a second ram air branch flow channel SAC2, an outlet-side ram air flow channel AC1, and an exhaust port 5. Among them, the first ram air branch flow channel SAC1 and the second ram air branch flow channel SAC2 are connected in parallel between the inlet-side ram air flow channel AC0 and the outlet-side ram air flow channel AC1. The air inlet 4 is provided with an inlet damper 41 and an inlet damper actuator 42 for adjusting the opening of the inlet damper 41, and the exhaust port 5 is provided with an exhaust damper 51 and an exhaust damper actuator 52 for adjusting the exhaust damper 51. In addition, in the present embodiment, a ram cavity AC2 is formed in the outlet-side ram air flow channel AC1, and a ram cavity fan ACF is arranged in the ram cavity AC2. Here, the reasons for setting the ram chamber AC2 and the ram chamber fan ACF are explained. Generally speaking, when the aircraft is on the ground or flying at low altitude, the ram pressure heads inside and outside the aircraft are small and the required amount of ram air cannot be formed. In order to form the required amount of ram air to meet the temperature control requirements of the environmental control system S, the ram chamber AC2 and the ram chamber fan ACF arranged in the ram chamber AC2 are set. Specifically, under the action of the ram chamber fan ACF, a sufficiently large ram pressure head is formed inside and outside the fuselage of the ram air flow channel AC, and a large amount of air outside the aircraft is sucked into the ram air flow channel AC through the air inlet 4 of the ram air flow channel AC. The ram air sucked into the ram air flow channel AC is divided into the first ram air branch flow channel SAC1 and the second ram air branch flow channel SAC2 according to the specified amount under the control of the environmental control system S. Then, after the above-mentioned ram air is merged in the ram chamber AC2 of the ram air flow channel AC1 on the outlet side, it flows out to the outside of the aircraft through the exhaust port 5 under the action of the ram chamber fan ACF.

[0064] like Figure 1As shown, in the first ram air branch flow channel SAC1, the auxiliary cooling heat exchanger 33 of the auxiliary cooling subsystem SS3, the first cooling heat exchanger 11 and the second cooling heat exchanger 13 of the air cycle refrigeration subsystem SS1 are arranged in the first ram air branch flow channel SAC1 in a manner of being connected in series with respect to the ram air flowing in the first ram air branch flow channel SAC1 and in this order. In addition, a water ejector 6 is provided at a portion of the first ram air branch flow channel SAC1 on the upstream side of the auxiliary cooling heat exchanger 33, and the water ejector 6 is connected to the water separator 16 in the air cycle refrigerant subsystem SS1 so that the liquid water in the water separator 16 can flow to the water ejector 6. The water injector 6 can spray the above-mentioned liquid water to the first ram air branch flow channel SAC1, so that the liquid water, driven by the ram air, contacts the auxiliary cooling heat exchanger 33 and the first cooling heat exchanger 11 and the second cooling heat exchanger 13, thereby cooling the auxiliary cooling heat exchanger 33 and the first cooling heat exchanger 11 and the second cooling heat exchanger 13, thereby improving the heat exchange efficiency of the auxiliary cooling heat exchanger 33 and the first cooling heat exchanger 11 and the second cooling heat exchanger 13.

[0065] On the other hand, the first air preparation heat exchanger 21 and the second air preparation heat exchanger 23 of the air preparation subsystem SS2 are arranged in the second ram air branch flow passage SAC2. In addition, a ram air flow control valve CV is provided in the middle of the second ram air branch flow passage SAC2 to adjust the amount of ram air flowing in the second ram air branch flow passage SAC2.

[0066] The above describes the air circulation refrigeration subsystem SS1, the air preparation subsystem SS2, and the auxiliary cooling subsystem SS3 constituting the hot side (hot circuit) of the environmental control system S of this embodiment, and the ram air flow channel AC constituting the cold side (cold circuit) of the environmental control system S of this embodiment. Figures 1 to 3 , the closed-loop control of the bleed air or refrigerant temperature of each subsystem based on the integrated controller IC is explained.

[0067] However, before explaining the closed-loop control using the integrated controller IC, the physical principle underlying the closed-loop control described below will be explained.

[0068] In the existing environmental control system, since a ram air flow channel is independently formed for each subsystem, the temperature control for each subsystem is independent, which results in the problem of ram air waste and a separate controller is required for each subsystem, making the entire control system complicated.

[0069] In order to overcome the above technical problems and taking into account the principle of energy cascade utilization, an integrated centralized temperature closed-loop control based on an integrated controller IC is adopted in this embodiment, so as to fully utilize the cooling energy of the ram air, reduce the ram air intake volume and excessive waste of ram air, and simplify the entire control system.

[0070] Furthermore, it is known that in an environmental control system of a civil aircraft, the air cycle refrigeration subsystem SS1 has a greater cooling energy requirement for ram air than the air preparation subsystem SS2 and the auxiliary cooling subsystem SS3 .

[0071] Therefore, the integrated controller IC first performs closed-loop control on the temperature of the bleed air in the air cycle refrigeration subsystem SS1.

[0072] Specifically, first, the integrated controller IC receives the actual temperature of the bleed air at the downstream outlet of the air cycle refrigeration subsystem SS1, i.e., the portion of the second pipeline P2 close to the ventilation system V, detected by the first temperature controller TS1. Next, the integrated controller IC compares the received actual temperature of the bleed air with the target refrigeration temperature pre-stored in the integrated controller IC. If the actual temperature of the bleed air is higher or lower than the target refrigeration temperature within a certain range, the integrated controller IC controls the air inlet damper actuator 42 and the exhaust damper actuator 52 to adjust the opening of the air inlet damper 41 and the exhaust damper 51, thereby adjusting the ram air volume in the ram air flow channel AC. It should be noted that, since the pipe diameters and internal flow resistances of the first ram air branch flow channel SAC1 and the second ram air branch flow channel SAC2 are pre-designed, under a certain flight condition, when the total flow of ram air in the ram air flow channel AC is determined, the ram air volume in the first ram air branch flow channel SAC1 and the ram air volume in the second ram air branch flow channel SAC2 are determined (at this time, the opening of the ram air flow control valve CV in the second ram air branch flow channel SAC2 is fixed). Therefore, it can also be said that the integrated controller IC adjusts the ram air volume in the first ram air branch flow channel SAC1 by adjusting the opening of the air inlet damper 41 and the exhaust damper 51. At the same time, the integrated controller IC adjusts the opening of the first bypass valve BV1 set in the first bypass pipeline BP1 to change the amount of bleed air flowing in the first bypass pipeline BP1, thereby changing the mixing flow ratio of the bleed air in the air circulation refrigeration subsystem SS1. Thus, the ram air volume in the first ram air branch channel SAC1 and the mixing flow ratio of the bleed air in the air circulation refrigeration subsystem SS1 are adjusted simultaneously and repeatedly until the actual temperature of the bleed air reaches the preset target refrigeration temperature, thereby achieving closed-loop temperature control of the bleed air.

[0073] Next, after the actual temperature of the bleed air in the air circulation refrigeration subsystem SS1 reaches the preset target refrigeration temperature, the integrated controller IC preferably further performs closed-loop control of the bleed air temperature in the air preparation subsystem SS2 and / or closed-loop control of the refrigerant temperature in the auxiliary cooling subsystem SS3.

[0074] Specifically, when the actual temperature of the bleed air in the air circulation refrigeration subsystem SS1 reaches the preset target refrigeration temperature and the closed-loop control of the bleed air temperature in the air preparation subsystem SS2 is desired, the integrated controller IC receives the actual temperature of the bleed air at the downstream outlet of the air preparation subsystem SS2, i.e., the fourth pipeline P4, near the inerting system B, detected by the second temperature sensor TS2. Then, the integrated controller IC compares the received actual temperature of the bleed air with the target air preparation temperature pre-stored in the integrated controller IC. If the actual temperature of the bleed air is higher or lower than the target air preparation temperature within a certain range, the integrated controller IC adjusts the opening of the second bypass valve BV2 set in the second bypass pipeline BP2 to change the amount of bleed air flowing in the second bypass pipeline BP2, thereby changing the mixing flow ratio of the bleed air in the air preparation subsystem SS2. Thus, by adjusting the mixing flow ratio of the bleed air in the air preparation subsystem SS2, the actual temperature of the bleed air reaches the preset target air temperature, thereby realizing the closed-loop control of the temperature of the bleed air. In addition, when the amount of ram air flowing in the second ram air branch flow channel SAC2 is too large, the integrated controller IC adjusts the opening of the ram air flow control valve CV to reduce the ram air amount.

[0075] On the other hand, when the actual temperature of the bleed air of the air circulation refrigeration subsystem SS1 reaches the preset target refrigeration temperature and the closed-loop control of the refrigerant temperature in the auxiliary cooling subsystem SS3 is desired, the integrated controller IC receives the actual temperature of the refrigerant in the liquid storage tank 32 of the auxiliary cooling subsystem SS3 or near the inlet of the liquid storage tank 32 detected by the third temperature sensor TS3. Then, the integrated controller IC compares the received actual temperature of the refrigerant with the target auxiliary cooling temperature pre-stored in the integrated controller IC. If the actual temperature of the refrigerant is higher or lower than the target auxiliary cooling temperature within a certain range, the integrated controller IC adjusts the opening of the third bypass valve BV3 set in the third bypass line BP3 to change the amount of refrigerant flowing in the third bypass line BP3, thereby changing the mixing flow ratio of the refrigerant in the auxiliary cooling subsystem SS3. At the same time, the integrated controller IC also adjusts the rotation speed of the compressor 34 for auxiliary cooling. By simultaneously adjusting the mixing flow ratio of the refrigerant in the auxiliary cooling subsystem SS3 and the rotation speed of the auxiliary cooling compressor 34, the actual temperature of the refrigerant reaches the preset target auxiliary cooling temperature, thereby realizing closed-loop control of the refrigerant temperature.

[0076] In this way, through the integrated control based on the integrated controller IC, the principle of energy cascade utilization can be fully followed and the cooling energy of the ram air can be fully released. At the same time, compared with the independent control of each subsystem in the existing environmental control system, the configuration of the controller can be simplified and the control system can be simplified.

[0077] Furthermore, the present invention can freely combine the various embodiments within the scope of the present invention, or can appropriately modify or omit the various embodiments.

Claims

1. An environmental control system for a civil aircraft, comprising an air cycle refrigeration subsystem having a refrigeration heat exchanger, an air preparation subsystem having an air preparation heat exchanger, an auxiliary cooling subsystem having an auxiliary cooling heat exchanger, and a ram air flow channel having a ram air inlet and a ram air outlet, characterized in that: The ram air flow channel includes a first ram air branch flow channel and a second ram air branch flow channel connected in parallel, The auxiliary cooling heat exchanger and the cooling heat exchanger are arranged in the first ram air branch flow channel, and the air preparation heat exchanger is arranged in the second ram air branch flow channel.

2. The environmental control system for a civil aircraft according to claim 1, characterized in that: A water ejector is provided at a portion of the first ram air branch flow channel upstream of the auxiliary cooling heat exchanger and the cooling heat exchanger, and the water ejector ejects water into the first ram air branch flow channel.

3. The environmental control system for a civil aircraft according to claim 1, characterized in that: The second ram air branch flow channel is provided with a ram air flow rate control valve, and the ram air flow rate control valve adjusts the flow rate of the ram air flowing in the second ram air branch flow channel.

4. The environmental control system for a civil aircraft according to claim 1, characterized in that: The refrigeration heat exchanger comprises a first refrigeration heat exchanger located upstream and a second refrigeration heat exchanger located downstream which are connected in series. The first refrigeration heat exchanger is connected to an air source system for supplying bleed air located upstream, and the second refrigeration heat exchanger is connected to a ventilation system located downstream. The first refrigeration heat exchanger is connected to a first bypass pipeline that bypasses the second refrigeration heat exchanger and is directly connected to the ventilation system.

5. The environmental control system for a civil aircraft according to claim 4, characterized in that: It also includes an integrated controller, which adjusts the flow rate of the ram air flowing in the first ram air branch flow channel and the flow rate of the bleed air flowing in the first bypass duct according to the difference between the temperature of the bleed air at the downstream outlet of the air circulation refrigeration subsystem and the target refrigeration temperature, so that the temperature of the bleed air at the downstream outlet of the air circulation refrigeration subsystem reaches the target refrigeration temperature.

6. The environmental control system for a civil aircraft according to claim 4, characterized in that: The air preparation heat exchanger includes a first air preparation heat exchanger located upstream and a second air preparation heat exchanger located downstream, which are connected in series. The first air preparation heat exchanger is connected to an air source system for supplying bleed air located upstream, and the second air preparation heat exchanger is connected to an inerting system located downstream. The first air preparation heat exchanger is connected to a second bypass line that bypasses the second air preparation heat exchanger and is directly connected to the inerting system.

7. The environmental control system for a civil aircraft according to claim 6, characterized in that: The system further includes an integrated controller, which adjusts the flow rate of the ram air flowing in the first ram air branch flow channel and the flow rate of the bleed air flowing in the first bypass line according to the difference between the temperature of the bleed air at the downstream outlet of the air cycle refrigeration subsystem and the target refrigeration temperature, so that the temperature of the bleed air at the downstream outlet of the air cycle refrigeration subsystem reaches the target refrigeration temperature. When the temperature of the bleed air at the downstream outlet of the air circulation refrigeration subsystem reaches the target refrigeration temperature, the integrated controller adjusts the flow rate of the bleed air flowing in the second bypass duct according to the difference between the temperature of the bleed air at the downstream outlet of the air preparation subsystem and the target air preparation temperature, so that the temperature of the bleed air at the downstream outlet of the air preparation subsystem reaches the target air preparation temperature.

8. The environmental control system for a civil aircraft according to claim 4, characterized in that: The auxiliary cooling subsystem includes a refrigerant circuit connected to an evaporator, a liquid storage tank, the auxiliary cooling heat exchanger, and a compressor, wherein the refrigerant circuit is used for refrigerant circulation. The refrigerant circuit is formed with a third bypass line that bypasses the auxiliary cooling heat exchanger.

9. The environmental control system for a civil aircraft according to claim 8, characterized in that: The system further includes an integrated controller, which adjusts the flow rate of the ram air flowing in the first ram air branch flow channel and the flow rate of the bleed air flowing in the first bypass line according to the difference between the temperature of the bleed air at the downstream outlet of the air cycle refrigeration subsystem and the target refrigeration temperature, so that the temperature of the bleed air at the downstream outlet of the air cycle refrigeration subsystem reaches the target refrigeration temperature. When the temperature of the bleed air at the downstream outlet of the air circulation refrigeration subsystem reaches the target refrigeration temperature, the integrated controller adjusts the flow rate of the refrigerant flowing in the third bypass line and the speed of the compressor according to the difference between the temperature of the refrigerant in the liquid storage tank of the auxiliary cooling subsystem and the target auxiliary cooling temperature, so that the temperature of the refrigerant in the liquid storage tank of the auxiliary cooling subsystem reaches the target auxiliary cooling temperature.

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