Aero-engine high-altitude test bed

Abstract

The utility model discloses an aero-engine high altitude test bed, high altitude test bed includes high altitude test chamber, cooling cooling unit, first heat exchange unit, second heat exchange unit, mixes and mixes pressure stabilizing unit, oxygen supply unit, air compressor unit, drying unit, heating unit, refrigeration unit, air extractor unit, oxygen concentration detection unit, pressure detection unit, flow detection unit and each valve. The utility model discloses the original air supply air compressor unit and air extractor air compressor combination is a set of air compressor unit, and the semi -open of the air -exhausted entrance high altitude test chamber of the air -exhausted of the original from the atmosphere into high altitude test chamber, and the air -exhausted of the air -exhausted entrance high altitude test chamber of the outlet high altitude test chamber again, greatly reduced the construction cost and energy consumption of high altitude test bed, reduced the peak and valley wave difference of operation / non - operation stage energy consumption, thereby reduced the impact to regional power grid.

Description

Technical Field

[0001] This utility model belongs to the field of aero-engine testing technology, and in particular relates to an aero-engine high-altitude test stand. Background Technology

[0002] An aero-engine high-altitude test stand (hereinafter referred to as a high-altitude stand) is a large-scale experimental device that can simulate the in-flight working environment of an aero-engine on the ground and obtain experimental data such as the engine's high-altitude performance / characteristics. The high-altitude stand artificially creates high-altitude flight conditions (speed, temperature, pressure, etc.) on the ground, making the engine installed on the ground function as if it were operating at high altitude, thereby verifying and evaluating whether the engine's performance meets design requirements.

[0003] In recent years, the explosive growth of the drone market and the overall improvement of the domestic aero-engine technology have led to an increasingly frequent demand for high-altitude test facilities. However, high-altitude test facilities are still scarce in China. The main reason for this is the huge energy (electricity) consumption during the operation of high-altitude test facilities and the huge peak-valley difference in energy consumption during operation and non-operation phases, which has a significant impact on the local energy supply system.

[0004] Regarding energy conservation in high-altitude test benches, there has been considerable technological accumulation and patent achievements. For example, patent document CN209244671U discloses an energy absorption and conversion device for a high-altitude simulation test bench of an aero-engine; patent document CN116952030A discloses a waste heat recovery device, system, and method for an indoor test bench of an aero-engine; and patent document CN115419484A discloses an energy storage and carbon sequestration system applied to the gas cooling process of a test bench. These studies mainly focus on the absorption, conversion, and reuse of energy in a specific unit of the high-altitude test bench. Patent documents such as CN109115506A, which discloses a method for using an engine test bench intake system, and CN110763472A, which discloses an engine test bench and its testing method, focus on energy conservation by shortening the overall testing time through improvements in the design of the test bench itself, the debugging and calibration process, and the testing methods.

[0005] The aforementioned existing technologies have all proposed certain technical solutions for the energy-saving design of high-altitude test stations, but they mainly focus on the energy recovery and utilization of local equipment in the high-altitude test station or the optimization of the overall test process. There is little research on smoothing out the huge peak-valley difference in energy consumption during operation and non-operation phases and reducing the overall energy consumption of the system. They cannot solve the huge impact of high-altitude test stations on the regional power grid. Utility Model Content

[0006] The purpose of this invention is to provide a high-altitude test stand for aero-engines to solve the problem of huge energy consumption during the operation phase of traditional high-altitude test stands, as well as the huge peak-valley difference in energy consumption during the operation / non-operation phases, which has a huge impact on the regional power grid.

[0007] This utility model solves the above-mentioned technical problems through the following technical solution: a high-altitude test stand for aero-engines, comprising a high-altitude test chamber, a cooling unit, a first heat exchange unit, a second heat exchange unit, a mixing and stabilizing unit, an oxygen supply unit, an air compressor unit, a drying unit, a heating unit, a refrigeration unit, an air extraction unit, an oxygen concentration detection unit, a pressure detection unit, a flow detection unit, and various valves.

[0008] The outlet of the oxygen supply unit is connected to the first heat exchange unit, the second heat exchange unit, and the blending and stabilizing unit. The outlet of the air compressor unit is connected to the blending and stabilizing unit through the second heat exchange unit. The outlet of the air compressor unit is also directly connected to the blending and stabilizing unit. The outlet of the blending and stabilizing unit is connected to the heating unit, the drying unit, and the high-altitude test chamber. The drying unit is connected to the refrigeration unit and the high-altitude test chamber. The heating unit and the refrigeration unit are respectively connected to the high-altitude test chamber. The high-altitude test chamber is connected to the air extraction unit through the cooling and temperature reduction unit. The cooling and temperature reduction unit is also connected to the inlet of the air compressor unit through the first heat exchange unit.

[0009] A first vent branch is provided at the outlet of the air compressor unit, and a second vent branch is provided at the outlet of the extraction unit; a first valve and a second valve are sequentially provided on the pipeline between the oxygen supply unit and the blending and stabilizing unit; the inlet of the air compressor unit is also connected to a first air intake, a third valve is provided on the first air intake, and a fourth valve is provided on the pipeline between the third valve and the inlet of the air compressor unit; a fifth valve is provided on the first vent branch; a sixth valve is provided on the pipeline between the blending and stabilizing unit and the high-altitude test chamber; a seventh valve is provided on the pipeline between the blending and stabilizing unit and the drying unit; an eighth valve is provided on the pipeline between the blending and stabilizing unit and the heating unit; a ninth valve is provided on the pipeline between the drying unit and the refrigeration unit; a tenth valve is provided on the pipeline between the drying unit and the high-altitude test chamber; an eleventh valve is provided on the pipeline between the cooling and heat dissipation unit and the extraction unit; the inlet of the extraction unit is also connected to a second air intake, a twelfth valve is provided on the second air intake, and a thirteenth valve is provided on the second vent branch;

[0010] The oxygen concentration detection unit is used to detect the oxygen concentration in the test environment, and to control the first valve and the eleventh valve according to the oxygen concentration in the test environment, so as to adjust the oxygen concentration in the overall balanced state and make the oxygen concentration in the test environment meet the test requirements. The pressure detection unit is used to detect the pressure in the test environment, and to control the third valve, the fourth valve and the fifth valve according to the pressure in the test environment, so as to make the pressure in the test environment meet the test requirements. The flow rate detection unit is used to detect the flow rate in the test environment, and to control the power of the air compressor unit, so that the flow rate in the test environment meets the test requirements.

[0011] Furthermore, the oxygen concentration detection unit is located at the outlet of the blending and stabilizing unit, the pressure detection unit is located on the pipeline between the air compressor unit and the first heat exchange unit, and the flow detection unit is located on the pipeline at the inlet of the high-altitude test chamber.

[0012] Furthermore, the oxygen supply unit includes a liquid oxygen tank group, a pump and a vaporizer connected in sequence, with both ends of the vaporizer connected to the first heat exchange unit.

[0013] Furthermore, the drying unit includes a heat exchanger and a drying tower, and the refrigeration unit is a turboexpander unit.

[0014] Furthermore, exhaust silencers are installed at the ends of the first and second venting branches.

[0015] Furthermore, the air compressor unit includes multiple centrifugal compressors, and a check valve is provided at the outlet and second vent branch of each centrifugal compressor.

[0016] Furthermore, the first, second, third, sixth, ninth, tenth, eleventh, and twelfth valves are all electric valves, the fourth, fifth, and thirteenth valves are all regulating valves, and the seventh and eighth valves are all shut-off valves.

[0017] Furthermore, the cooling unit includes a spray device and a cold water jacket. The cold water jacket is fitted onto the pipeline between the high-altitude test chamber and the air extraction unit, and the spray device is located around the pipeline between the high-altitude test chamber and the air extraction unit.

[0018] Furthermore, the air compressor unit includes multiple centrifugal compressors, and a check valve is provided at the outlet and second vent branch of each centrifugal compressor.

[0019] Furthermore, the blending and stabilizing unit includes multiple blending and stabilizing tanks, each of which corresponds to a second valve and an oxygen concentration detection unit; some of the blending and stabilizing tanks are connected to a heating unit to input high-temperature mixed gas into the high-altitude test chamber; some of the blending and stabilizing tanks are connected to a drying unit and a high-pressure test chamber to input dry low-temperature mixed gas, dry room-temperature gas, or room-temperature gas into the high-altitude test chamber.

[0020] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0021] The high-altitude test stand for aero-engines provided by this utility model combines the air supply compressor unit and the air extraction compressor unit in the original high-altitude test stand into a single air compressor unit. This transforms the original semi-open system of drawing air from the atmosphere into the high-altitude test chamber and then expelling it into a circulating system where air is drawn from the high-altitude test chamber outlet into the high-altitude test chamber inlet. Even considering the increased pressure ratio requirements when combining into a single air compressor unit for the same testing needs, this utility model still significantly reduces the construction cost and energy consumption of the high-altitude test stand. Furthermore, this utility model is equipped with a first heat exchange unit and a second heat exchange unit, saving energy. Compared to the original high-altitude test stand, the overall operating power is reduced by approximately 30% or more.

[0022] Because the overall operating power of the high-altitude test stand for aero-engines of this invention is greatly reduced, the peak-valley difference in energy consumption during operation and non-operation phases is reduced, thereby reducing the impact of the peak-valley difference on the regional power grid.

[0023] This invention improves the response speed after test start-up and state changes by adjusting the fourth and fifth valves before and after the air compressor unit, and effectively avoids air compressor unit surge. Compared with the original high-altitude test bench that requires linkage adjustment of the air supply air compressor unit and the air extraction air compressor unit, this invention greatly reduces the time between test conditions and further improves power efficiency.

[0024] Compared to the original high-altitude test stand's air supply compressor unit and air extraction compressor unit linkage mode, the circulation formed by this utility model greatly reduces the direct contact between the intake and exhaust sections and the atmosphere, thus reducing the construction investment in noise control for the high-altitude test stand. Attached Figure Description

[0025] To more clearly illustrate the technical solution of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1This is a schematic diagram of the structure of the high-altitude test stand for an aero-engine in this embodiment of the present invention.

[0027] Explanation of reference numerals in the attached diagram: 1-Liquid oxygen tank assembly, 2-Pump, 3-First heat exchange unit, 4-Air compressor unit, 5-Second heat exchange unit, 6-Blending and pressure stabilizing unit, 7-Drying unit, 8-Flow detection unit, 9-Pressure detection unit, 10-Oxygen concentration detection unit, 11-First valve, 12-Second valve, 13-Third valve, 14-Fourth valve, 15-Fifth valve, 16-Sixth valve, 17-Seventh valve, 18-Eighth valve, 19-Ninth valve, 20-Tenth valve, 21-Eleventh valve, 22-Twelfth valve, 23-Thirteenth valve, 24-Check valve, 25-Fourteenth valve. Detailed Implementation

[0028] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] The technical solution of this utility model will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0030] To address the significant energy consumption during the operation of traditional high-altitude test benches, as well as the substantial impact on regional power grids caused by the large peak-to-valley difference in energy consumption during operation and non-operation phases, this invention provides a high-altitude test bench for aero-engines. This bench combines the original air supply compressor unit and exhaust compressor unit into a single air compressor unit, and further incorporates a heat exchange unit design, thereby greatly reducing overall operating power and saving energy.

[0031] Figure 1 A schematic diagram of the high-altitude test stand for aero-engines provided by this utility model is shown. Figure 1 As shown, the high-altitude test stand for aero-engines includes a high-altitude test chamber, a cooling unit, a first heat exchange unit 3, a second heat exchange unit 5, a blending and stabilizing unit 6, an oxygen supply unit, an air compressor unit 4, a drying unit 7, a heating unit, a refrigeration unit, an air extraction unit, an oxygen concentration detection unit 10, a pressure detection unit 9, a flow detection unit 8, and various valves.

[0032] The outlet of the oxygen supply unit is connected to the first heat exchange unit 3, the second heat exchange unit 5, and the blending and stabilizing unit 6. The outlet of the air compressor unit 4 is connected to the blending and stabilizing unit 6 through the second heat exchange unit 5. The outlet of the air compressor unit 4 is also directly connected to the blending and stabilizing unit 6. The outlet of the blending and stabilizing unit 6 is connected to the heating unit, the drying unit 7, and the high-altitude test chamber. The drying unit 7 is connected to the refrigeration unit and the high-altitude test chamber. The heating unit and the refrigeration unit are respectively connected to the high-altitude test chamber. The high-altitude test chamber is connected to the air extraction unit through the cooling and temperature reduction unit. The cooling and temperature reduction unit is also connected to the inlet of the air compressor unit 4 through the first heat exchange unit 3.

[0033] A first vent branch is provided at the outlet of air compressor unit 4, and a second vent branch is provided at the outlet of the extraction unit; a first valve 11 and a second valve 12 are sequentially provided on the pipeline between the oxygen supply unit and the mixing and stabilizing unit 6; the inlet of air compressor unit 4 is also connected to a first air intake, and a third valve 13 is provided on the first air intake; a fourth valve 14 is provided on the pipeline between the third valve 13 and the inlet of air compressor unit 4; a fifth valve 15 is provided on the first vent branch; a sixth valve 16 is provided on the pipeline between the mixing and stabilizing unit 6 and the high-altitude test chamber. A seventh valve 17 is provided on the pipeline between the mixing and stabilizing unit 6 and the drying unit 7; an eighth valve 18 is provided on the pipeline between the mixing and stabilizing unit 6 and the heating unit; a ninth valve 19 is provided on the pipeline between the drying unit 7 and the refrigeration unit; a tenth valve 20 is also provided on the pipeline between the drying unit 7 and the high-altitude test chamber; an eleventh valve 21 is provided on the pipeline between the cooling and heat dissipation unit and the air extraction unit; the inlet of the air extraction unit is also connected to the second air intake duct; a twelfth valve 22 is provided on the second air intake duct; and a thirteenth valve 23 is provided on the second venting branch.

[0034] The pipeline between the outlet of air compressor unit 4 and the inlet of the high-pressure test chamber is designed as a positive pressure pipeline, while the pipeline between the outlet of the high-pressure test chamber and the inlet of air compressor unit 4 is designed as a negative pressure pipeline. The positive pressure at the inlet of the high-pressure test chamber is converted into airflow velocity through the nozzle to simulate flight conditions, while the negative pressure at the outlet simulates flight altitude. Air enters air compressor unit 4 through the first air intake, the third valve 13, and the fourth valve 14. After being pressurized by air compressor unit 4, it is delivered to the mixing and stabilizing unit 6. Oxygen output from the oxygen supply unit is delivered to the mixing and stabilizing unit 6 through the first valve 11 and the second valve 12. Within the mixing and stabilizing unit 6, air and oxygen are mixed and pressure stabilized, outputting a mixed gas. Based on the required test temperature, the mixed gas enters the high-altitude test chamber via four paths: The first path is: the mixed gas is heated by the eighth valve 18 and the heating unit, then fed into the high-altitude test chamber as a high-temperature mixed gas; the second path is: the mixed gas is dried and cooled by the seventh valve 17, the drying unit 7, the ninth valve 19, and the refrigeration unit, then fed into the high-altitude test chamber as a dry, low-temperature mixed gas; the third path is: the mixed gas is dried by the seventh valve 17, the drying unit 7, and the tenth valve 20, then fed into the high-altitude test chamber as a dry, room-temperature mixed gas; the fourth path is: the mixed gas is fed into the high-altitude test chamber as a room-temperature mixed gas via the sixth valve 16. The high-temperature exhaust gas from the high-altitude test chamber outlet is cooled by the cooling unit and then divided into two paths: one path is drawn into the atmosphere by the air extraction unit to ensure overall balance while maintaining a constant oxygen concentration; the other path is cooled by the first heat exchange unit 3 and then enters the air compressor unit 4, where it is pressurized and then sent to the mixing and stabilizing unit 6 to form a cycle.

[0035] The oxygen concentration detection unit 10 is used to detect the oxygen concentration in the test environment, and to control the first valve 11 and the eleventh valve 21 according to the oxygen concentration in the test environment, so as to achieve the overall balance of oxygen concentration adjustment and make the oxygen concentration in the test environment meet the test requirements. The pressure detection unit 9 is used to detect the pressure in the test environment, and to control the third valve 13, the fourth valve 14 and the fifth valve 15 according to the pressure in the test environment, so as to make the pressure in the test environment meet the test requirements. The flow detection unit 8 is used to detect the flow rate in the test environment, and to control the power of the air compressor unit 4, so that the flow rate in the test environment meets the test requirements.

[0036] The control of each valve and piece of equipment can be achieved manually or by the control unit. When achieved by the control unit, the control unit controls the first valve 11 and the eleventh valve 21 according to the oxygen concentration of the test environment to adjust the oxygen concentration in an overall balanced state, ensuring that the oxygen concentration of the test environment meets the test requirements; it controls the third valve 13, the fourth valve 14, and the fifth valve 15 according to the test environment pressure to ensure that the test environment pressure meets the test requirements; and it controls the power of the air compressor unit 4 according to the test environment flow rate to ensure that the test environment flow rate meets the test requirements. By adjusting the oxygen concentration, pressure, and flow rate, the working environment of an aero-engine is simulated to achieve the performance testing of the aero-engine.

[0037] This invention relates to a high-altitude test stand for aero-engines. It combines the supply air compressor unit 4 and the extraction air compressor unit 4, which have similar principles but opposite functions at both ends of the original high-altitude test stand, into a single air compressor unit 4, forming a circulation system. This single air compressor unit 4 achieves the required air supply pressure and high-altitude test chamber vacuum. Through the rational design of the extraction unit and oxygen supply unit, the stability of oxygen concentration during the circulation process is ensured. The configuration of the first heat exchange unit 3 and the second heat exchange unit 5 enables internal energy exchange between multiple cold and heat sources, reducing the energy consumption for additional heating and cooling. This invention reduces the construction cost and energy consumption of the high-altitude test stand, saves energy, reduces overall operating power, and thus reduces the peak-to-valley difference in energy consumption during operation and non-operation phases, thereby reducing the impact of this peak-to-valley difference on the regional power grid.

[0038] In a specific embodiment of this utility model, the oxygen concentration detection unit 10 is located at the outlet of the mixing and stabilizing unit 6, the pressure detection unit 9 is located on the pipeline between the air compressor unit 4 and the first heat exchange unit 3, and the flow detection unit 8 is located on the pipeline at the entrance of the high-altitude test chamber.

[0039] In a specific embodiment of this utility model, the oxygen supply unit includes a liquid oxygen tank group 1, a pump 2 and a vaporizer connected in sequence, with both ends of the vaporizer connected to the first heat exchange unit 3.

[0040] The liquid oxygen output from liquid oxygen tank group 1 is vaporized by a vaporizer and exchanges heat with the first heat exchange unit 3, thereby increasing the oxygen temperature. Through internal energy exchange, there is no need to add an additional oxygen heating device, thus avoiding the energy consumption of additional heating.

[0041] A valve is also installed on the pipeline between the first heat exchange unit 3 and the vaporizer. The flow rate during heat exchange can be adjusted by the valve, thereby regulating the temperature of oxygen and the exhaust gas flowing into the air compressor unit 4.

[0042] In a specific embodiment of this utility model, the drying unit 7 includes a heat exchanger and a drying tower, the refrigeration unit is a turboexpander unit, and the heating unit is an electric heater.

[0043] In a specific embodiment of this utility model, an exhaust silencer tower is also provided at the end of the first venting branch and the second venting branch, which reduces the noise generated to the outside world during exhaust.

[0044] In a specific embodiment of this utility model, the air compressor unit 4 includes multiple centrifugal compressors, and a check valve 24 is provided at the outlet and second vent branch of each centrifugal compressor. The check valve at the outlet of each centrifugal compressor prevents internal backflow when some centrifugal compressors are operating and others are not. A cooler is also provided at the outlet of each centrifugal compressor to reduce the air temperature output from the centrifugal compressor to 50℃~70℃, protecting the subsequent compressed air pipes and the mixing and stabilizing unit 6.

[0045] In the specific embodiments of this utility model, the first valve 11, the second valve 12, the third valve 13, the sixth valve 16, the ninth valve 19, the tenth valve 20, the eleventh valve 21 and the twelfth valve 22 are all electric valves, the fourth valve 14, the fifth valve 15 and the thirteenth valve 23 are all regulating valves, and the seventh valve 17 and the eighth valve 18 are both shut-off valves.

[0046] In a specific embodiment of this utility model, the cooling unit includes a spray device and a cold water jacket. The cold water jacket is fitted onto the pipe between the high-altitude test chamber and the air extraction unit, and the spray device is located around the pipe between the high-altitude test chamber and the air extraction unit.

[0047] The temperature of the high-temperature exhaust gas output from the high-altitude test chamber is reduced by spraying cold water through a cooling water jacket and a spray device.

[0048] In a specific embodiment of this utility model, a third vent branch is added to the pipeline between the mixing and stabilizing unit 6 and the seventh valve 17, a fourteenth valve 25 is provided on the third vent branch, and an exhaust silencer tower is provided at the end of the third vent branch.

[0049] In a specific embodiment of this utility model, the blending and stabilizing unit 6 includes multiple blending and stabilizing tanks, each of which corresponds to a second valve 12 and an oxygen concentration detection unit 10; some blending and stabilizing tanks are connected to a heating unit to input high-temperature mixed gas into the high-altitude test chamber; some blending and stabilizing tanks are connected to a drying unit 7 and directly connected to a high-pressure test chamber to input dry low-temperature mixed gas, dry room temperature gas, or room temperature gas into the high-altitude test chamber.

[0050] A method for testing an engine under test using the aforementioned high-altitude test stand for aero-engines includes the following steps:

[0051] Before the test begins, the air compressor unit 4 is started simultaneously with the start of the air extraction unit. The air extraction unit draws air to ensure that the test environment meets the vacuum requirements. The air compressor unit 4 pressurizes the gas output from the cooling unit and then delivers it to the mixing and stabilizing unit 6. Depending on the required test temperature, the high-pressure gas is stabilized by the mixing and stabilizing unit 6 and then selected to be delivered to the high-altitude test chamber from either the heating unit (i.e., outputting high-temperature mixed gas), the drying unit 7 and pipeline (i.e., outputting dry room-temperature mixed gas), the drying unit 7 and refrigeration unit (i.e., outputting dry low-temperature mixed gas), or the pipeline (i.e., outputting room-temperature mixed gas), forming a cycle.

[0052] Based on the oxygen concentration detected by the oxygen concentration detection unit 10, the first valve 11 and the eleventh valve 21 are controlled to adjust the oxygen concentration in an overall balanced state, ensuring that the oxygen concentration in the test environment meets the test requirements. Based on the test environment pressure detected by the pressure detection unit 9, the third valve 13, the fourth valve 14, and the fifth valve 15 are controlled to ensure that the test environment pressure meets the test requirements. Based on the test environment flow rate detected by the flow rate detection unit 8, the power of the air compressor unit 4 is controlled to ensure that the test environment flow rate meets the test requirements. When the oxygen concentration, pressure, flow rate, and temperature of the test environment meet the corresponding test requirements, the test begins.

[0053] During the test phase, the high-temperature exhaust gas from the outlet of the high-altitude test chamber is cooled by the cooling unit. Part of it is drawn into the atmosphere by the air extraction unit, while the other part is cooled by the first heat exchange unit 3 and enters the air compressor unit 4. After being pressurized by the air compressor unit 4, it is sent to the mixing and stabilizing unit 6. At the same time, the oxygen vaporized by the first heat exchange unit 3 is introduced into the mixing and stabilizing unit 6 to increase the pressure in the mixing and stabilizing unit 6. After temperature regulation, it is sent to the high-altitude test chamber to complete the cycle.

[0054] During the testing phase, the oxygen concentration detection unit 10, pressure detection unit 9, and flow detection unit 8 monitored the test environment in real time.

[0055] When the oxygen concentration in the test environment is less than the required concentration, the opening of the first valve 11 is increased to increase the oxygen concentration, and the opening of the eleventh valve 21 is increased to increase the proportion of circulating exhaust gas discharged, thus achieving overall oxygen concentration adjustment under balanced conditions. When the oxygen concentration in the test environment is greater than the required concentration, the opening of the first valve 11 is decreased to decrease the oxygen concentration, and the opening of the eleventh valve 21 is decreased to reduce the proportion of circulating exhaust gas discharged, thus achieving overall oxygen concentration adjustment under balanced conditions.

[0056] When the test environment pressure is lower than the test requirement pressure, open the third valve 13 and increase the opening of the fourth valve 14 to increase the air volume, that is, to introduce a certain amount of air from the atmosphere into the circulation system; when the test environment pressure is higher than the test requirement pressure, open the fifth valve 15 to exhaust air to the outside through the fifth valve 15.

[0057] When the test environment flow rate is less than the test requirement flow rate, increase the power of air compressor unit 4; when the test environment flow rate is greater than the test requirement flow rate, decrease the power of air compressor unit 4.

[0058] During the test condition switching or exit phase, the third valve 13, the fourth valve 14, and the fifth valve 15 are controlled according to the test environment pressure to adjust the test environment pressure until the test requirement pressure is met and stabilized. Then, the third valve 13 and the fifth valve 15 are closed to continue operation.

[0059] In a specific embodiment of this utility model, when the test environment pressure decreases and the oxygen concentration decreases, causing the pumping unit to be unable to pump air to the outside, the twelfth valve 22 is opened to allow air to enter through the second air inlet, enabling the pumping unit to pump air to the outside.

[0060] If the intake airflow of the aero-engine is m and the fuel flow rate is M, then the exhaust flow rate at the high-altitude test chamber outlet is m0 = m + M. Under the premise that the test conditions remain unchanged, to maintain overall cycle balance, the extraction flow rate of the air extraction unit and the oxygen supply flow rate should be the same. Assuming the aero-engine is calculated based on the optimal air-fuel ratio (15:1), and the oxygen content in the exhaust flow rate at the high-altitude test chamber outlet is 13%, then the air compressor flow rate m2 and the extraction flow rate or oxygen supply flow rate m1 of the air extraction unit are:

[0061] m = m2 + m1 (1)

[0062] m1 + 13%m2 = 21%m(2)

[0063] According to formulas (1) and (2), we can get: m≈10m1.

[0064] Taking a certain aero-engine (with an intake flow rate m of 10 kg / s and a fuel flow rate M of 0.65 kg / s) as an example, the air compressor flow rate m2 of the high-altitude test stand of this utility model is 8.4 kg / s, the exhaust gas extraction rate m1 is 1.6 kg / s, and the oxygen replenishment rate m1 is 1.6 kg / s. This utility model achieves an overall design where the air compressor flow rate m2 is less than the aero-engine flow rate by specifying the intake flow rate m and fuel flow rate M of the aero-engine generator under test, and by using formulas (1) and (2) to configure the air compressor flow rate, exhaust gas extraction rate, and oxygen replenishment rate.

[0065] Based on the requirements of aero-engine testing, the pressure ratio of the pressure control unit should be rationally configured. Let the pressure of the test environment vacuum be P1, the required pressure at the inlet of the high-altitude test chamber be P2, and the atmospheric pressure be P. Then, the pressure ratio N1 of the extraction unit and the pressure ratio N2 of the air compressor unit are:

[0066] N1 = P1 / P (4)

[0067] N2 = P2 / P (5)

[0068] The vacuum pressure P1 of the extreme test environment is 5 kPa, and the required pressure P2 at the inlet of the high-altitude test chamber is 1.0 mPa. According to formulas (4) and (5), the pressure ratio N1 of the extraction unit is 22, and the pressure ratio N2 of the air compressor unit is 220. In the actual commissioning process, further optimization can be made according to the site conditions. For example, increasing the pressure of oxygen entering the mixing and stabilizing unit can reduce the pressure ratio N2 of the air compressor unit to 100. When configuring the pressure ratio of the air compressor, the pressure ratio N1 of the extraction unit and the pressure ratio N2 of the air compressor unit can be determined by clarifying the test state of the aero-engine under test and using formulas (4) and (5). The pressure ratio of the air compressor unit can be reduced by increasing the pressure of oxygen entering the mixing and stabilizing unit, so that it is lower than the pressure ratio of the supply and extraction pressure difference.

[0069] The liquid oxygen tank capacity is configured based on the test duration of the aero-engine. If the oxygen supply volume is m1, then the relationship between the liquid oxygen tank capacity V and the single test duration t is as follows:

[0070]

[0071] Where ρ represents the oxygen density under standard conditions.

[0072] Taking a maximum test duration of 6 hours for a certain aero-engine as an example, the storage capacity V of the liquid oxygen tank group is 30m³. 3 .

[0073] The above description only discloses specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or modifications that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-altitude test stand for an aero-engine, characterized in that, The high-altitude test bench includes a high-altitude test chamber, a cooling unit, a first heat exchange unit, a second heat exchange unit, a mixing and stabilizing unit, an oxygen supply unit, an air compressor unit, a drying unit, a heating unit, a refrigeration unit, an air extraction unit, an oxygen concentration detection unit, a pressure detection unit, a flow detection unit, and various valves. The outlet of the oxygen supply unit is connected to the first heat exchange unit, the second heat exchange unit, and the blending and stabilizing unit. The outlet of the air compressor unit is connected to the blending and stabilizing unit through the second heat exchange unit. The outlet of the air compressor unit is also directly connected to the blending and stabilizing unit. The outlet of the blending and stabilizing unit is connected to the heating unit, the drying unit, and the high-altitude test chamber. The drying unit is connected to the refrigeration unit and the high-altitude test chamber. The heating unit and the refrigeration unit are respectively connected to the high-altitude test chamber. The high-altitude test chamber is connected to the air extraction unit through the cooling and temperature reduction unit. The cooling and temperature reduction unit is also connected to the inlet of the air compressor unit through the first heat exchange unit. A first vent branch is provided at the outlet of the air compressor unit, and a second vent branch is provided at the outlet of the extraction unit; a first valve and a second valve are sequentially provided on the pipeline between the oxygen supply unit and the blending and stabilizing unit; the inlet of the air compressor unit is also connected to a first air intake, a third valve is provided on the first air intake, and a fourth valve is provided on the pipeline between the third valve and the inlet of the air compressor unit; a fifth valve is provided on the first vent branch; a sixth valve is provided on the pipeline between the blending and stabilizing unit and the high-altitude test chamber; a seventh valve is provided on the pipeline between the blending and stabilizing unit and the drying unit; an eighth valve is provided on the pipeline between the blending and stabilizing unit and the heating unit; a ninth valve is provided on the pipeline between the drying unit and the refrigeration unit; a tenth valve is provided on the pipeline between the drying unit and the high-altitude test chamber; an eleventh valve is provided on the pipeline between the cooling and heat dissipation unit and the extraction unit; the inlet of the extraction unit is also connected to a second air intake, a twelfth valve is provided on the second air intake, and a thirteenth valve is provided on the second vent branch; The oxygen concentration detection unit is used to detect the oxygen concentration in the test environment, and to control the first valve and the eleventh valve according to the oxygen concentration in the test environment, so as to adjust the oxygen concentration in the overall balanced state and make the oxygen concentration in the test environment meet the test requirements. The pressure detection unit is used to detect the pressure in the test environment, and to control the third valve, the fourth valve and the fifth valve according to the pressure in the test environment, so as to make the pressure in the test environment meet the test requirements. The flow rate detection unit is used to detect the flow rate in the test environment, and to control the power of the air compressor unit, so that the flow rate in the test environment meets the test requirements.

2. The high-altitude test stand for aero-engines according to claim 1, characterized in that, The oxygen concentration detection unit is located at the outlet of the blending and stabilizing unit, the pressure detection unit is located on the pipeline between the air compressor unit and the first heat exchange unit, and the flow detection unit is located on the pipeline at the inlet of the high-altitude test chamber.

3. The high-altitude test stand for aero-engines according to claim 1, characterized in that, The oxygen supply unit includes a liquid oxygen tank group, a pump and a vaporizer connected in sequence, with both ends of the vaporizer connected to the first heat exchange unit.

4. The high-altitude test stand for aero-engines according to claim 1, characterized in that, The drying unit includes a heat exchanger and a drying tower, and the refrigeration unit is a turboexpander unit.

5. The high-altitude test stand for aero-engines according to claim 1, characterized in that, An exhaust silencer tower is also installed at the end of the first and second venting branches.

6. The high-altitude test stand for aero-engines according to claim 1, characterized in that, The air compressor unit includes multiple centrifugal compressors, and each centrifugal compressor outlet and second vent branch is equipped with a check valve.

7. The high-altitude test stand for aero-engines according to claim 1, characterized in that, The first, second, third, sixth, ninth, tenth, eleventh, and twelfth valves are all electric valves; the fourth, fifth, and thirteenth valves are all regulating valves; and the seventh and eighth valves are both shut-off valves.

8. The high-altitude test stand for aero-engines according to claim 1, characterized in that, The cooling unit includes a spray device and a cold water jacket. The cold water jacket is fitted onto the pipe between the high-altitude test chamber and the air extraction unit, and the spray device is located around the pipe between the high-altitude test chamber and the air extraction unit.

9. The high-altitude test stand for aero-engines according to claim 1, characterized in that, The air compressor unit includes multiple centrifugal compressors, and a check valve is provided at the outlet and in the second vent branch of each centrifugal compressor.

10. The high-altitude test stand for aero-engines according to any one of claims 1 to 9, characterized in that, The blending and stabilizing unit includes multiple blending and stabilizing tanks, each of which corresponds to a second valve and an oxygen concentration detection unit; some of the blending and stabilizing tanks are connected to a heating unit to input high-temperature mixed gas into the high-altitude test chamber; some of the blending and stabilizing tanks are connected to a drying unit and a high-pressure test chamber to input dry low-temperature mixed gas, dry room-temperature gas, or room-temperature gas into the high-altitude test chamber.

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