A helicopter equipment compartment environmental control system and control method

Abstract

The present application belongs to the technical field of airborne environmental control / thermal management, and relates to a helicopter equipment cabin environmental control system and a control method. The system comprises a cold source assembly, a heat source assembly, an equipment cabin environmental control assembly and an environmental control control box. The equipment cabin environmental control system collects hot air at the outlet of an oil cooler to warm and control the humidity of the equipment cabin, only reduces the relative humidity of the air, and does not reduce the moisture content of the air. Therefore, the air humidity in the equipment cabin is maintained within a suitable range, and the reliability and safety of electronic equipment are improved. Energy is saved and carbon emission is reduced: compared with the traditional humidity control method, the system collects waste heat from oil, realizes the effect of controlling humidity without additional energy consumption, thereby reducing energy consumption and carbon dioxide emission.

Description

Technical Field

[0001] This invention belongs to the field of airborne environmental control / thermal management technology, and relates to an environmental control system and control method for a helicopter equipment compartment. Background Technology

[0002] Below 9 km, the atmosphere contains both dry air and water vapor; this mixture is generally referred to as humid air. Although the water vapor content in humid air is very low, its variations cause changes in the air's dryness and humidity, directly impacting human comfort, environmental control processes, and the reliability of electronic equipment. Helicopters typically fly below 9 km, operating in a humid atmospheric environment, especially in southern my country and coastal areas where relative humidity is high.

[0003] As the helicopter climbs from near the ground to high altitude, the temperature of the outside air gradually decreases, and the temperature inside the equipment cabin also gradually decreases. As the temperature drops, the saturated humidity of the air inside the equipment cabin decreases, and the excess water vapor in the air condenses into water droplets. The condensed water droplets may exist on the bottom of the equipment cabin, the bulkhead panels, the surface of some electronic equipment, etc.

[0004] As the helicopter returns from high altitude to near the ground, the humidity of the outside atmosphere gradually increases. The air temperature inside the equipment cabin, the bulkhead panels, and the surface temperature of electronic equipment are low and do not rise above the air dew point temperature in time. As a result, water droplets will condense on the bulkhead panels and some electronic equipment surfaces.

[0005] If liquid water is present on the electrical connectors or internal circuit boards of electronic devices, it may affect the normal operation of the electronic devices. If this happens to important or critical electronic devices, it will pose a great threat to the flight safety of helicopters. Summary of the Invention

[0006] Purpose of the invention

[0007] In view of the above problems, the present invention proposes an environmental control system configuration and control method that can control the temperature inside the equipment compartment and prevent condensation and moisture buildup inside the equipment compartment.

[0008] Technical solution

[0009] A helicopter equipment compartment environmental control system includes a cold source component, a heat source component, an equipment compartment environmental control component, and an environmental control box 18.

[0010] The cold source assembly includes an evaporator assembly 1, a compressor 2, a condenser assembly 3, and an expansion valve 4. The outlet of the evaporator assembly 1 is connected to the suction port of the compressor 2 through a refrigerant suction pipe. The discharge port of the compressor 2 is connected to the inlet of the condenser assembly 3 through a hot gas pipe. The outlet of the condenser assembly 3 is connected to the inlet of the expansion valve 4 through a liquid supply pipe. The outlet of the expansion valve 4 is connected to the inlet of the evaporator assembly 1 through a liquid supply pipe.

[0011] The heat source components include an oil radiator 19, an oil cooling fan 20, a main reducer 21, a main reducer oil temperature sensor 22, an oil tank 23, an oil temperature sensor 24, and an oil pump 25. In the oil radiator 19, the air drawn in by the oil cooling fan 20 exchanges heat with the oil in the oil radiator 19, increasing the temperature of the drawn-in air. The oil in the oil radiator 19 cools down and returns to the main reducer 21 through the oil pipeline. After lubricating and absorbing heat in the main reducer 21, the oil enters the oil tank 23 through the oil pipeline. The oil tank 23 is equipped with an oil temperature sensor 24 for detecting the oil temperature. The oil pump 25 draws oil from the oil tank 23 and delivers it to the oil radiator 19.

[0012] The equipment compartment environmental control assembly includes a cold path regulating valve 5, a hot path regulating valve 7, a temperature sensor 8, and a temperature and humidity sensor 16. The cold path regulating valve 5 is used to regulate the airflow in the cold air duct of the cold source assembly, and the hot path regulating valve 7 is used to regulate the airflow in the hot air duct of the hot source assembly. A temperature sensor 8 is installed on the main pipeline after the cold and hot air ducts merge to detect the air temperature at the equipment compartment inlet. The main pipeline extends into the equipment compartment to provide cold and hot air sources. The temperature and humidity sensor 16 is installed in the equipment compartment to sense the temperature and relative humidity of the air inside the equipment compartment. The environmental control box 18 controls the start and stop of the cold source assembly and adjusts the opening of the cold path regulating valve 5 and the hot path regulating valve 7 by sensing the temperature and relative humidity signals from the temperature and humidity sensor 16, thereby controlling the temperature and relative humidity inside the equipment compartment.

[0013] Furthermore, it also includes an oil filter 26, which is disposed between the oil tank 23 and the oil pump 25 to filter impurities in the oil.

[0014] Furthermore, it also includes an air intake assembly 6, which is located in the main reduction chamber, near the outlet of the lubricating oil radiator, to collect hot air from the outlet of the lubricating oil radiator 19.

[0015] Furthermore, after the main pipeline enters the equipment compartment, it is divided into several distribution pipelines 11. Each branch is equipped with a flow-limiting ring 9 to distribute the air volume as needed, and to accurately control the temperature and humidity of electronic devices 10 with different heating powers.

[0016] Furthermore, it also includes an air outlet 17, which is installed on the equipment compartment skin for air circulation. The air outlet 17 should face downward and backward, not forward, to prevent rainwater from entering.

[0017] Furthermore, the thermal circuit regulating valve 7 should be a valve with good sealing performance and low leakage, capable of opening and closing quickly, and stepless adjustment.

[0018] Furthermore, the cold circuit regulating valve 5 should be a valve designed to prevent condensation, such as by using insulation measures or non-metallic materials, to prevent condensation from forming on the valve body surface and entering the equipment compartment under low temperature conditions.

[0019] Furthermore, the air supply pipes connecting the air inlet assembly 6, the hot circuit regulating valve 7, and the cold circuit regulating valve 5 are all insulated pipes to prevent the loss of heat or cold from the air.

[0020] Furthermore, the temperature and humidity sensor 16 should be installed near important / critical equipment in the equipment compartment to monitor the temperature and relative humidity of the air near the important / critical equipment in real time to ensure flight safety.

[0021] A control method for an environmental control system in a helicopter equipment compartment includes the following steps:

[0022] Step 1) When the air temperature inside the equipment compartment ts≥t0 (t0 is the maximum allowable temperature), the hot circuit regulating valve 7 is closed and the cold circuit regulating valve 5 remains open. When ts<t0, the opening of the cold circuit regulating valve 5 remains unchanged.

[0023] Step 2) When ts is equal to or lower than the outside atmospheric temperature t0, the opening of the cold circuit regulating valve 5 is continuously reduced, while the hot circuit regulating valve 7 remains closed.

[0024] Step 3) During the cooling process of the equipment compartment, if the relative humidity of the air ψs≥ψ0 (ψ0 is the maximum allowable relative humidity), the cold circuit regulating valve 5 should be closed and the hot circuit regulating valve 7 should be kept open so that ts<t0 and ψs<ψ0.

[0025] Step 4) When ts≥t0 and ψs<ψ0, return to step 1) to control the system;

[0026] Step 5) When ts≥t0 and ψs≥ψ0, the opening of the hot circuit regulating valve 7 remains unchanged, and the cold circuit regulating valve 5 is opened to control the temperature of the mixed air so that ts<t0 and ψs<ψ0.

[0027] The beneficial effects of this application are as follows:

[0028] This invention patent uses a cooling source component to cool the equipment compartment and collects heat from the lubricating oil system to control humidity in the equipment compartment, thus creating a favorable temperature and humidity environment inside the equipment compartment. It has the following technical advantages:

[0029] 1) Improving helicopter flight safety: The relative humidity of the air inside the equipment cabin is crucial for the normal operation of electronic equipment. Excessively high or low humidity negatively impacts equipment performance and lifespan. High humidity can easily lead to short circuits, corrosion, and damage, while excessively low humidity can cause problems such as electrostatic discharge. The equipment cabin environmental control system collects hot air from the lubricating oil radiator outlet to heat and control the humidity of the equipment cabin. It only reduces the relative humidity of the air, without reducing the moisture content, thus maintaining the air humidity within the equipment cabin within a suitable range, improving the reliability and safety of electronic equipment.

[0030] 2) Energy saving and carbon emission reduction: Compared with traditional humidity control methods, this system collects the waste heat of lubricating oil, achieving the effect of humidity control without additional energy consumption, thereby reducing energy consumption and carbon dioxide emissions. Attached Figure Description

[0031] Figure 1 Design condition diagram for external atmospheric temperature;

[0032] Figure 2 Design condition diagram for external atmospheric humidity;

[0033] Figure 3 Enthalpy-humidity diagram of condensation for air cooling;

[0034] Figure 4 This is a schematic diagram of the configuration of the equipment compartment environmental control system;

[0035] Figure 5 Schematic diagram of the working principle of cooling air dissipation in the equipment compartment;

[0036] Figure 6 Diagram illustrating the working principle of hot air humidity control in the equipment compartment;

[0037] Figure 7 Enthalpy-humidity diagram for air temperature rise;

[0038] Figure 8 Diagram illustrating the working principle of temperature and humidity control in the equipment compartment;

[0039] Figure 9 This is the working logic diagram of the equipment compartment environmental control system. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar components or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this invention. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this invention, and should not be construed as limiting the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The embodiments of this invention will be described in detail below with reference to the accompanying drawings.

[0041] The present invention will now be described in further detail with reference to the accompanying drawings.

[0042] The main reducer lubrication system mainly consists of an oil radiator 19, an oil cooling fan 20, a main reducer 21, a main reducer lubrication temperature sensor 22, an oil tank 23, an oil temperature sensor 24, an oil pump 25, and an oil filter 26.

[0043] When the rotor rotates, the gear transmission mechanism of the main reducer drives the lubricating oil cooling fan 20 and the lubricating oil pump 25 to rotate simultaneously. The hot lubricating oil in the main oil tank at the bottom of the lubricating oil tank 23 is pressurized by the lubricating oil pump 25 and filtered through pipelines and lubricating oil filter 26 before being sent to the lubricating oil radiator 19 for heat exchange. The heat is drawn away by the outside atmosphere by the lubricating oil cooling fan 20, and the outside atmosphere absorbs the heat and its temperature rises.

[0044] After cooling, the lubricating oil is sent to the main oil circuit in the main gearbox 21 through the lubricating oil pipeline. The bearings and gears of the transmission mechanism of the main gearbox 21 are directly lubricated by the lubricating oil drawn from the main oil circuit. The hot lubricating oil after lubrication falls into the lower part of each unit of the main gearbox 21 by its own weight, and is then drawn by the lubricating oil pump 25 and collected in the oil sump of the lubricating oil tank 23 to start a new round of lubricating oil circulation. When the helicopter lubricating oil cooling system is working normally, the oil temperature is stable at about 90°C. If the outside air temperature is 20°C, the temperature will exceed 50°C after heat exchange with the lubricating oil.

[0045] In the summer in the south, the relative humidity of the air near the ground is high, usually above 65%. When a helicopter climbs rapidly from near the ground to higher altitudes, the air in the equipment cabin does not have enough time to be fully replaced, and the moisture content is still relatively high. As the flight altitude increases, the outside air temperature gradually decreases, and the equipment cabin and the outside air continuously exchange heat. The equipment cabin frame and bottom wall gradually cool down. When the temperature is lower than the dew point temperature of the air, water vapor in the air will condense into liquid water droplets on the bottom of the equipment cabin, the frame wall panels, and the surface of some electronic equipment.

[0046] When the equipment compartment environmental control system is activated, the cold circuit regulating valve 5 gradually opens. A portion of the cold air (approximately 12℃~15℃) from the evaporator assembly 1 in the cold source components flows through the cold circuit regulating valve 5 and is then delivered to the equipment compartment to cool the electronic equipment (the number of which is determined by the actual system). The temperature and humidity sensor 16 inside the equipment compartment feeds back temperature signals to the environmental control box 18. When the temperature inside the equipment compartment is higher than or equal to ts (determined by the actual model, e.g., 50℃), the cold circuit regulating valve 5 continues to open until it is fully open. When the temperature inside the equipment compartment is lower than ts, the cold circuit regulating valve 5 continues to close until it is fully closed.

[0047] Because the helicopter is at a high altitude and the outside air temperature is very low, the temperature inside the equipment compartment continues to decrease even after the cold circuit regulating valve 5 is fully closed. The temperature and humidity sensor 16 feeds back the relative humidity signal to the environmental control box 18. When the relative humidity reaches ψs (determined by the actual model, such as 90%), the hot circuit regulating valve 7 remains open. The hot air collected from the lubricating oil radiator by the air intake assembly 6 flows through the hot circuit regulating valve 7 and is delivered to the equipment compartment to heat the electronic equipment and the equipment compartment, thereby reducing the relative humidity of the air inside the equipment compartment.

[0048] During the heating and dehumidification process, if the temperature inside the equipment compartment fed by the temperature and humidity sensor 16 exceeds ts, the cold circuit regulating valve 5 opens, and the cold air from the evaporator assembly 1 and the hot air from the lubricating oil radiator 19 are mixed to a temperature of (determined by the actual model, such as 30℃) and delivered to the equipment compartment. The air temperature inside the equipment compartment is maintained within ts and the relative humidity is maintained below ψs.

[0049] like Figure 1 As shown, the temperature design conditions for the helicopter environmental control system in hot weather are based on the US standard MIL-STD-210A, which has a similar geographical latitude to my country. Starting from the ground, the lower air mass is heated and rises, expanding and cooling from high pressure to low pressure. The temperature decreases with altitude, with a decrease rate of approximately 6.5℃ / km. Based on the US standard MIL-STD-210A, which has a similar geographical latitude to my country, the temperature design conditions for the helicopter environmental control system in hot weather are as follows: Figure 1 .

[0050] like Figure 2 As shown, the humidity design conditions for the helicopter environmental control system in hot weather are based on the US standard MIL-STD-210A, which is similar to my country in terms of geographical latitude. When the h is below 3km, the change in the humidity content in the air is small; when the h is above 3km, as the temperature continues to drop, the excess water vapor in the air will condense into water droplets, and the saturated humidity content in the air will decrease.

[0051] like Figure 3As shown, assuming the air temperature inside the near-ground equipment cabin is 40℃ and the moisture content is 19g / kg dry air, it is at state point A on the enthalpy-humidity chart. When the helicopter ascends to 3km and cruises, the temperature inside the equipment cabin drops to 20℃, reaching state point B. At this point, the air inside the equipment cabin is saturated air with a relative humidity of 100%, and liquid water precipitates out. The precipitated liquid water is:

[0052] Δd=dB-dC

[0053] According to the enthalpy-humidity chart, dC = 14.7 g / kg dry air, dB = dA = 19 g / kg dry air, therefore Δd = 4.3 g / kg dry air.

[0054] Therefore, it can be seen that during the process of a helicopter climbing from near the ground to high altitude, if the conventional equipment cabin cooling system is used to continuously provide the equipment cabin with cold air from the outside atmosphere or the refrigeration system, the temperature inside the equipment cabin will drop rapidly. When the temperature drops below the air dew point temperature, a large amount of water vapor in the air inside the equipment cabin will condense, resulting in a large number of water droplets on the equipment cabin walls, floor and electronic equipment surfaces, and even water accumulation.

[0055] Similarly, when a helicopter descends from high altitude to the ground, the equipment cabin walls and floor are at low temperatures, while the relative humidity of the outside air near the ground is high. The outside air entering the equipment cabin can easily drop below the dew point temperature, which can also cause a large number of water droplets to appear on the equipment cabin walls, floor, and electronic equipment surfaces, and even water accumulation.

[0056] like Figure 4 As shown, a novel configuration of an environmental control system for a helicopter equipment compartment requires both a cold source and a heat source to prevent water vapor in the air inside the equipment compartment from condensing into liquid water. The cold source comes from a cold source component, and the heat source comes from the main anti-lubricating oil system. The temperature and humidity of the equipment compartment are controlled by adjusting the flow rate of cold air through the cold path regulating valve 5 and the flow rate of hot air through the hot path regulating valve 7.

[0057] like Figure 5 As shown, in hot weather near the ground, the equipment compartment environmental control system only uses the cooling function. The outside air temperature near the ground is high, and the temperature inside the equipment compartment is even higher, requiring the use of a cooling source component for rapid cooling. The cold circuit regulating valve 5 gradually opens, and a portion of the cold air (temperature approximately 12℃~15℃) from the evaporator assembly 1 flows through the cold circuit regulating valve 5 and is then delivered to the equipment compartment to cool the critical electronic equipment (the quantity is determined by the actual system). Based on the heat output of the critical electronic equipment, the airflow is adjusted through the flow-limiting ring 9 to achieve precise temperature control. The temperature and humidity sensor 16 inside the equipment compartment feeds back temperature signals to the environmental control box 18. When the temperature inside the equipment compartment is higher than or equal to ts (determined by the actual model, e.g., 50℃), the cold circuit regulating valve 5 continues to open until it is fully open. When the temperature inside the equipment compartment is lower than ts, the cold circuit regulating valve 5 continues to close until it is fully closed.

[0058] like Figure 6 As shown, during high-altitude flight, the equipment cabin environmental control system only uses the hot air humidity control function. At high altitudes, the outside air temperature is low, and the temperature inside the equipment cabin is also low, making condensation likely. Therefore, hot air heating is required to prevent water vapor from escaping from the air. Even after the cold-circuit regulating valve 5 is fully closed, the temperature inside the equipment cabin continues to decrease. The temperature and humidity sensor 16 feeds back a relative humidity signal to the environmental control box 18. When the relative humidity reaches ψs (determined by the actual model, e.g., 90%), the hot-circuit regulating valve 7 remains open. Hot air collected from the lubricating oil radiator by the air intake assembly 6 flows through the hot-circuit regulating valve 7 and is delivered to the equipment cabin, heating the electronic equipment and the equipment cabin, and reducing the relative humidity inside the equipment cabin.

[0059] like Figure 7 As shown, assuming the air temperature inside the near-ground equipment compartment is 40℃, the moisture content is 19g / kg dry air, and the relative humidity is 38.9%, it is at state point A on the enthalpy-humidity chart. During the helicopter's climb, the temperature inside the equipment compartment gradually decreases, while the relative humidity gradually increases. When the relative humidity rises to 90%, state point D is reached, at which point the air temperature inside the equipment compartment has dropped to 25.9℃. After heating the equipment compartment with lubricating oil-heated air (approximately 50℃), the air temperature begins to rise, increasing to 30℃, reaching state point E, and the relative humidity drops from 90% to 70%.

[0060] like Figure 8 As shown, when both the temperature and humidity inside the equipment compartment exceed the design critical values, the environmental control requirements of the equipment compartment cannot be met by a single function, and temperature and humidity control of the equipment compartment should be implemented. During the heating and dehumidification process, if the temperature inside the equipment compartment fed back by the temperature and humidity sensor 16 exceeds ts, the cold circuit regulating valve 5 opens, and the cold air from the evaporator assembly 1 and the hot air from the lubricating oil radiator 19 are mixed. The temperature of the mixed air is controlled and delivered to the equipment compartment, maintaining the air temperature inside the equipment compartment below ts and the relative humidity below ψs.

[0061] like Figure 9 As shown, the working logic of the equipment compartment environmental control system is as follows:

[0062] 1) When the air temperature inside the equipment compartment ts≥50℃, the hot circuit regulating valve 7 is closed and the cold circuit regulating valve 5 remains open. When ts<50℃, the opening of the cold circuit regulating valve 5 remains unchanged.

[0063] 2) When ts is equal to or lower than the outside atmospheric temperature t0, the opening of the cold circuit regulating valve 5 is continuously reduced, while the hot circuit regulating valve 7 remains closed.

[0064] 3) During the cooling process of the equipment compartment, if the relative humidity ψs ≥ 90%, the cold circuit regulating valve 5 should be closed and the hot circuit regulating valve 7 should be kept open to keep ts < 50℃ and ψs < 90%;

[0065] 4) When ts≥50℃ and ψs<90%, return to step 1) to control the system;

[0066] 5) When ts≥50℃ and ψs≥90%, the opening of the hot circuit regulating valve 7 remains unchanged, and the cold circuit regulating valve 5 is opened to control the temperature of the mixed air (determined by the actual model, such as 40℃) so that ts<50℃ and ψs<90%.

[0067] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein. The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Within the spirit and principles of the present invention, any person skilled in the art may use the disclosed technical content to make changes or modifications to create equivalent embodiments applicable to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention, any modifications, equivalent substitutions, improvements, etc., should be included within the protection scope of the present invention.

Claims

1. A helicopter equipment compartment environmental control system, characterized in that, The system comprises a cold source assembly, a heat source assembly, a device cabin environment control assembly, and an environment control control box. The cold source assembly comprises an evaporator assembly, a compressor, a condenser assembly, and an expansion valve. The heat source assembly comprises an oil radiator, an oil cooling fan, a main reducer, a main reduction oil temperature sensor, an oil tank, an oil temperature sensor, and an oil pump. The device cabin environment control assembly comprises a cold path regulating valve, a hot path regulating valve, a temperature sensor, and a temperature and humidity sensor.

2. The system of claim 1, wherein, The system further comprises an oil filter, which is arranged between the oil tank and the oil pump.

3. The system of claim 2, wherein, The system further comprises an air inlet assembly, which is arranged in the main reduction cabin and close to the outlet of the oil radiator.

4. The system of claim 3, wherein, The main pipeline is divided into several distribution pipelines after entering the device cabin, and each branch pipeline is provided with a flow limiting ring.

5. The system of claim 4, wherein, The system further comprises an air outlet, which is arranged on the device cabin skin.

6. The system of claim 5, wherein, The hot path regulating valve should be a valve with good sealing performance, small leakage, fast opening and closing, and stepless adjustment.

7. The system of claim 6, wherein, The cold path regulating valve should be a valve with anti-condensation water design.

8. The system of claim 7, wherein, The air supply pipeline connected with the air inlet assembly, the hot path regulating valve, and the cold path regulating valve is a heat preservation pipeline.

9. The system of claim 8, wherein, The temperature and humidity sensor should be installed near important or critical equipment in the device cabin to monitor the temperature and relative humidity of the air near the important or critical equipment in real time.

10. The control method of the system according to claim 9, comprising the following steps: Step 1) when the air temperature ts in the device cabin is greater than or equal to t0, t0 is the maximum allowable temperature, the hot path regulating valve is closed, and the cold path regulating valve is continuously opened; when ts is less than t0, the opening degree of the cold path regulating valve remains unchanged; Step 2) when ts is equal to or lower than the external atmospheric temperature t0, the opening degree of the cold path regulating valve is continuously reduced, and the hot path regulating valve remains in the closed state. Step 3) during the cooling process of the equipment cabin, if the relative humidity of air ψs≥ψ0, ψ0 is the maximum allowable relative humidity, then the cold path regulating valve should be closed, the hot path regulating valve should be kept open, ts < t0, ψs < ψ0; Step 4) when ts≥t0 and ψs<ψ0, return to step 1) to control the system; Step 5) when ts≥t0 and ψs≥ψ0, the opening of the hot path regulating valve is kept unchanged, the cold path regulating valve is opened, the temperature of mixed air is controlled, ts < t0, ψs < ψ0.

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