Exhaust system and method for high-altitude negative pressure turbine simulation test bench based on multi-stage series connection

Abstract

The invention discloses a high-altitude negative pressure turbine simulation test bench exhaust system and method based on multi-stage series connection, and the system is used for a turbine test section, and comprises an exhaust volute, a three-stage centrifugal device, a three-stage heat exchange device, and a noise elimination tower. An outlet of the exhaust volute is connected into the first-stage heat exchanger through a pipeline, and an atmosphere supplementing main valve and an atmosphere supplementing auxiliary valve are arranged on the pipeline. The third-stage centrifugal machine device is communicated with the silencing tower through a pipeline; and the third-stage heat exchange device and the third-stage centrifugal machine device are connected in series in a grading manner. Through the combination of the three-stage heat exchange device and the industrial-grade three-stage centrifugal device which are connected in series in a multi-stage mode, the high-altitude negative pressure turbine simulation test bed simulates various limiting working condition technical indexes of the turbine at the high altitude of ten thousand meters, the low-cost negative pressure pumping effect of the high-altitude negative pressure turbine simulation test bed is achieved, and the requirement for long-time work of the high-altitude negative pressure turbine simulation test bed can be met.

Description

Technical Field

[0001] The invention relates to the technical field of turbine test benches, and in particular to an exhaust system and method for a high-altitude negative pressure turbine simulation test bench based on multi-stage series connection. Background Art

[0002] The performance of aircraft engines, as the "heart" of an aircraft, is directly related to the safe operation of the aircraft. During high-altitude and high-speed operation, aircraft engines are exposed to extreme and harsh environmental conditions such as low pressure, thin air, high speed, and strong noise. The turbine is one of the components with the worst working environment. When flying at an altitude of 10,000 meters, the turbine Reynolds number will be reduced to 0.25×10 5 Below, which is much smaller than the self-modeling Reynolds number, its operating point pressure ratio, flow rate and other aerodynamic performance will change, the efficiency will drop sharply, and the high-altitude and high-speed performance of the aircraft will be restricted. Therefore, it is urgent to simulate the real working state of the turbine in the harsh environment of high altitude in the turbine test, especially the more realistic turbine exhaust negative pressure condition, which puts higher requirements on the exhaust system of the high-altitude turbine test bench.

[0003] The exhaust system of the high-altitude turbine test bench simulates the temperature, negative pressure, and flow conditions of the aircraft when flying at different altitudes by establishing different exhaust conditions. In order to simulate negative pressure, that is, pressure lower than a standard atmospheric pressure, the patent "An exhaust back pressure regulation system and method suitable for turbine test bench (CN 113588233 A)" proposes to use an ejector to inject gas into the exhaust pipe. Since the jet airflow is a high-speed and high-energy airflow, the pressure energy is converted into velocity energy through the ejection effect, so that the pressure in the exhaust pipe connection area is reduced to produce a vacuum, thereby simulating negative pressure conditions. The ejector design has a wide adjustment range and can be adjusted from positive pressure to negative pressure, but it requires a large gas source and has a high investment cost. The patent "Digital simulation method of high-altitude platform exhaust unit based on Simulink (CN 115585145 A)" simulates high-altitude negative pressure conditions by dynamically simulating the axial flow exhaust unit, but the installed power of a single unit of the real axial flow exhaust unit is more than tens of thousands of kilowatts, the equipment power is large, the test operation energy consumption is high, and there are safety hazards and test risks. Summary of the invention

[0004] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides an exhaust system and method for a high-altitude negative pressure turbine simulation test bench based on a multi-stage series connection.

[0005] The technical solution of the present invention to solve the above technical problems is: including an exhaust volute, a three-stage centrifuge device, a three-stage heat exchange device and a muffler; the outlet of the exhaust volute is connected to a first-stage heat exchanger through a pipeline, and an atmospheric air supply main valve and an atmospheric air supply auxiliary valve are arranged on the pipeline; the three-stage centrifuge device is connected to the muffler through a pipeline; the three-stage heat exchange device and the three-stage centrifuge device are connected in series in stages; the three-stage heat exchange device includes a first-stage heat exchanger, a second-stage heat exchanger and a third-stage heat exchanger; the three-stage centrifuge device includes a first-stage centrifuge unit, a second-stage centrifuge unit and a three-stage centrifugal unit; a first suction switch valve is arranged at the outlet of the first-stage heat exchanger, and the first suction switch valve is connected to the inlet of the first-stage centrifugal unit through a pipeline; a third suction switch valve is arranged at the outlet of the first-stage centrifugal unit, and the third suction switch valve is connected to the second-stage heat exchanger through a pipeline, the second-stage heat exchanger is connected to the second-stage centrifugal unit by a gas pipeline, the second-stage centrifugal unit is connected to the third-stage heat exchanger through the gas pipeline, and the third-stage heat exchanger is connected to the third-stage centrifugal unit through the gas pipeline; the three-stage centrifuge devices are all equipped with exhaust silencers and vent valves.

[0006] Furthermore, the outlet of the turbine test section is connected to an exhaust volute, and the exhaust volute adopts a constant flow velocity design in aerodynamic design. The exhaust velocity inside the exhaust volute is ≤50m / s, and the cross-section of the exhaust volute flow channel is circular.

[0007] Furthermore, a second suction switch valve is provided on the gas pipeline branch at the outlet of the first-stage heat exchanger, and the second suction switch valve is connected to the inlet of the second-stage heat exchanger.

[0008] An exhaust method based on an exhaust system of a multi-stage series-connected high-altitude negative pressure turbine simulation test bench comprises the following steps:

[0009] S 1 , Centrifugal unit flow matching: The unit's inlet flow quality , where is the inlet gas density, is the air intake speed, is the cross-sectional area of ​​the inlet pipe; then calculate the inlet flow volume , based on the flow-pressure ratio performance curve of the first-stage centrifugal unit, select the pressure ratio , where is the total inlet pressure of the centrifugal unit, is the total outlet pressure of the centrifugal unit; the outlet flow rate is ; According to the gas continuity equation , and the gas state equation , deduce the gas density after passing through the vacuum unit , and its corresponding flow volume is The exit speed is ; Heat exchangers are added between each level of heat exchange to cool the compressed gas to , then the intake air mass of the next centrifugal unit is ; The pressure loss during the cooling process is , and the pressure loss of gas flow in the pipeline is , then the next stage intake pressure ratio is , based on the flow-pressure ratio performance curve of the two-stage centrifugal unit, select the pressure ratio Similarly, the flow rate of the last two stages is matched so that the outlet flow of the three-stage centrifugal unit meets the mass flow conservation law. At the same time, the total pressure ratio of the three-stage centrifugal device ,ensure , is standard atmospheric pressure;

[0010] S 2 , obtain the centrifugal unit speed: according to the flow rate provided by the predetermined test conditions and negative pressure , combined with the centrifugal unit flow pressure ratio performance curve, and the pressure ratios of the first-stage centrifugal unit, the second-stage centrifugal unit, and the third-stage centrifugal unit are obtained respectively 、 、 , the corresponding speed is , , ;

[0011] S 3 , exhaust negative pressure: close the atmospheric air supply main valve and auxiliary valve regulated by the turbine to ensure that the air suction of the centrifugal device enters the exhaust tower through its own vent valve; start the turbine vacuum machine inside the first-stage centrifugal unit, the second-stage centrifugal unit, and the third-stage centrifugal unit in sequence, open the built-in vent valve, fully exhaust the air through centrifugal exhaust method, and adjust to the predetermined speed , , ; Open the atmospheric air supply main valve for regulating turbine intake, and gradually close the vent valve of the centrifugal device at the same time, and control the negative pressure state by adjusting the atmospheric air supply auxiliary valve and the frequency conversion control of the centrifugal device to generate a predetermined negative pressure at the outlet of the exhaust volute; the high-temperature gas is sucked through the negative pressure generated by the exhaust unit, and is gradually cooled down through the heat exchange device, and finally flows into the silencer tower for silencing and cooling treatment before being discharged into the atmosphere.

[0012] Furthermore, the second suction switch valve connects the gas discharged from the exhaust volute to the secondary centrifugal unit through the branch gas pipeline, and closes the first suction switch valve and the third suction switch valve.

[0013] The technical effects of the present invention are:

[0014] 1. The present invention uses a centrifugal vacuum pump for vacuum operation. Compared with the traditional method, it significantly reduces the construction cost of the test bench in terms of construction investment scale, operation economy, and technical difficulty of construction and operation. At the same time, it has a compact structure and saves a lot of space.

[0015] 2. The exhaust negative pressure system of the present invention adopts a combination of three-stage heat exchange and three-stage centrifugal device to generate the required negative pressure at the outlet of the turbine test section. The staged heat exchange method reduces the impact of high temperature on centrifugal extraction and improves the working margin of the overall system, thereby simulating the operating state of the turbine in a high-altitude low Reynolds number environment, solving the problem of existing technology in simulating the negative pressure limit of high-altitude turbine test bench.

[0016] 3. The present invention includes three groups of industrial-grade centrifugal exhaust units, among which the main features of the single-unit turbine vacuum machine used are high efficiency, low energy consumption and low efficiency, so as to meet the technical requirements of long-term continuous work; it is equipped with a complete automatic control system, which provides a technical basis for studying the operating status of the turbine under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 It is a simplified structural flow chart of the present invention;

[0019] Figure 3 This is the flow-pressure ratio performance curve of the first-stage centrifugal unit;

[0020] Figure 4 It is the flow-pressure ratio performance curve of the two-stage centrifugal unit;

[0021] Figure 5 This is the flow-pressure ratio performance curve of the three-stage centrifugal unit.

[0022] 1. Turbine test section; 2. Exhaust volute; 3. First-stage heat exchanger; 4. First-stage centrifugal unit; 5. Second-stage heat exchanger; 6. Silencer tower; 7. Second-stage centrifugal unit; 8. Third-stage heat exchanger; 9. Third-stage centrifugal unit; 10. First suction switch valve; 11. Second suction switch valve; 12. Third suction switch valve; 13. Atmospheric air supply main valve; 14. Atmospheric air supply auxiliary valve. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0024] like Figure 1As shown, the present invention provides an exhaust system of a high-altitude negative pressure turbine simulation test bench based on a multi-stage series connection, comprising a turbine test section 1, an exhaust volute 2, a three-stage centrifuge device, a three-stage heat exchange device and a muffler; the outlet of the exhaust volute 2 is connected to a first-stage heat exchanger 3 through a pipeline, and an atmospheric air supply main valve 13 and an atmospheric air supply auxiliary valve 14 are arranged on the pipeline; the three-stage centrifuge device is connected to the muffler through a pipeline; the three-stage heat exchange device and the three-stage centrifuge device are connected in series in stages.

[0025] The three-stage heat exchange device comprises a primary heat exchanger 3, a secondary heat exchanger 5 and a tertiary heat exchanger 8; the primary heat exchanger 3 is connected to the inlet of the primary centrifugal unit 4 through a pipeline.

[0026] The three-stage centrifuge device comprises a first-stage centrifuge unit 4, a second-stage centrifuge unit 7 and a third-stage centrifuge unit 9; a first suction switch valve 10 is arranged at the outlet of the first-stage heat exchanger 3; the first suction switch valve 10 is connected to the first-stage centrifuge unit 4 through a pipeline; a third suction switch valve 12 is arranged at the outlet of the first-stage centrifuge unit 4; the third suction switch valve 12 is connected to the second-stage heat exchanger 5 through a pipeline; the second-stage heat exchanger 5 is connected to the second-stage centrifuge unit 7 through a pipeline, the second-stage centrifuge unit 7 is connected to the third-stage heat exchanger 8 through a pipeline, and the third-stage heat exchanger 8 is connected to the third-stage centrifuge unit 9 through a pipeline; the three-stage centrifuge devices are all equipped with an exhaust silencer and a vent valve.

[0027] The exhaust volute 2 adopts a constant flow velocity design in aerodynamic design; the exhaust velocity inside the exhaust volute 2 is ≤50m / s; and the flow channel cross section of the exhaust volute 2 adopts a circular shape with strong pressure resistance.

[0028] The gas pipeline branch at the outlet of the exhaust volute 2 is provided with a first suction switch valve and a second suction switch valve, wherein the first suction switch valve controls the gas to pass to the inlet of the primary heat exchanger 3, and the second suction switch valve controls the gas to pass to the inlet of the secondary heat exchanger 5.

[0029] In one embodiment of the present invention, Figure 2 The following process introduces a method for exhaust negative pressure extraction suitable for high-altitude turbine test benches, including the following steps:

[0030] S 1 , Centrifugal unit flow matching: The unit's inlet flow quality , where is the inlet gas density, is the air intake speed, is the cross-sectional area of ​​the inlet pipe; then calculate the inlet flow volume , based on the flow-pressure ratio performance curve of centrifugal unit 1, select the pressure ratio , where is the total inlet pressure of the centrifugal unit, is the total outlet pressure of the centrifugal unit; the outlet flow rate is ; According to the gas continuity equation , and the gas state equation , deduce the gas density after passing through the vacuum unit , and its corresponding flow volume is The exit speed is ; In order to prevent the temperature from overheating during the multiple compression of the gas, this system adds a heat exchanger between each stage of heat exchange to cool the compressed gas to , then the intake air mass of the next centrifugal unit is ; There will be pressure loss during the cooling process , and the pressure loss of gas flow in the pipeline is , then the next stage intake pressure ratio is , based on the flow pressure ratio performance curve of the next level centrifugal unit 2, select the pressure ratio Similarly, the flow rate of the last two stages is matched so that the outlet flow of the three-stage centrifugal unit meets the mass flow conservation law. At the same time, the total pressure ratio of the three-stage centrifugal device ,ensure , The three-stage centrifugal device used in this system can reasonably distribute the pressure ratio so that each stage of the centrifugal unit can achieve the maximum utilization efficiency, ensure the coordinated match between the flow rate and the total pressure ratio, and avoid the unit from entering the surge area during operation.

[0031] S 2 , obtain the centrifugal unit speed: according to the flow rate provided by the predetermined test conditions and negative pressure , combined with the centrifugal unit flow pressure ratio performance curve, and the pressure ratios of the first-stage centrifugal unit, the second-stage centrifugal unit, and the third-stage centrifugal unit are obtained respectively 、 、 , the corresponding speed is , , .

[0032] S 3 , exhaust under negative pressure: close the atmospheric air supply main valve and auxiliary valve regulated by the turbine to ensure that the air sucked by the centrifugal device enters the exhaust tower through its own vent valve; start the turbine vacuum machines inside the first-stage centrifugal unit 4, the second-stage centrifugal unit 7, and the third-stage centrifugal unit 8 in sequence, open the built-in vent valve, fully exhaust the air through centrifugal exhaust method, and adjust to the predetermined speed , , ; Open the atmospheric air supply main valve 11 for regulating the turbine intake, and gradually close the vent valve of the centrifugal device at the same time, and control the negative pressure state by adjusting the atmospheric air supply auxiliary valve 12 and the frequency conversion control of the centrifugal device to generate a predetermined negative pressure at the outlet of the exhaust volute 2; the high-temperature gas is sucked through the negative pressure generated by the exhaust unit, and is gradually cooled down through the heat exchange device, and finally flows into the silencer tower 6 for silencer and cooling treatment before being discharged into the atmosphere.

[0033] In the present invention, the three-stage heat exchange device cools down the gas entering the centrifugal unit respectively, and exchanges heat with the gas through cold water. The three heat exchangers can achieve the effect of cooling the gas to below 50°, making the negative pressure extraction effect generated by the centrifugal unit more significant.

[0034] Figure 3 , Figure 4 and Figure 5 The characteristic curves of gas flow and corresponding pressure ratio at different speeds for the first-stage centrifugal unit, the second-stage centrifugal unit and the third-stage centrifugal unit of the present invention are shown respectively. According to the working conditions of different turbine states, including intake pressure and intake flow, the pressure ratio of each centrifugal unit is calculated through the characteristic curve of the three-stage centrifugal device, and the negative pressure function of the turbine test section is realized as a whole. This design can set a predetermined negative pressure effect under a larger design operating condition range, so that the high-altitude simulation of the high-altitude turbine test bench is more in line with the needs.

[0035] In one embodiment of the present invention, according to the flow pressure ratio characteristic curve of the three-stage centrifugal device, the three-stage heat exchange and three-stage centrifugal combination can achieve a minimum negative pressure of 0.12 bar; the pressure ratios of the first-stage centrifugal unit, the second-stage centrifugal unit, and the third-stage centrifugal unit are 2.17, 2.26, and 2.29, respectively. Using the formula Calculated Before entering the centrifugal unit, the high-temperature gas is cooled to 50°C through the heat exchanger; the pressure loss of the gas flow in the pipeline includes the pressure loss of the heat exchanger and the pressure loss of the overall pipeline elbow, which is =0.09bar; when discharged into the atmosphere, The pressure difference with the outside atmosphere is 0.1 bar, which is enough to compensate for the overall pipeline pressure difference. Considering the 10% margin, the total pressure increase ratio of the centrifugal unit is 9.2, which is less than the current maximum total pressure ratio of 12.26 of the unit, and has sufficient capacity to achieve a minimum negative pressure of 0.12 bar.

Claims

1. An exhaust system and method for a high-altitude negative pressure turbine simulation test bench based on a multi-stage series connection, used in a turbine test section, characterized in that: It includes an exhaust volute, a three-stage centrifuge device, a three-stage heat exchange device and a muffler; the outlet of the exhaust volute is connected to the first-stage heat exchanger through a pipeline, and an atmospheric air supply main valve and an atmospheric air supply auxiliary valve are arranged on the pipeline; the three-stage centrifuge device is connected to the muffler through a pipeline; the three-stage heat exchange device is connected in series with the three-stage centrifuge device in stages; the three-stage heat exchange device includes a first-stage heat exchanger, a second-stage heat exchanger and a third-stage heat exchanger; the three-stage centrifuge device includes a first-stage centrifuge unit, a second-stage centrifuge unit and a third-stage centrifuge unit; a first suction switch valve is arranged at the outlet of the first-stage heat exchanger, and the first suction switch valve is connected to the inlet of the first-stage centrifuge unit through a pipeline; a third suction switch valve is arranged at the outlet of the first-stage centrifuge unit, and the third suction switch valve is connected to the second-stage heat exchanger through a pipeline, the second-stage heat exchanger is connected to the second-stage centrifuge unit by a gas pipeline, the second-stage centrifuge unit is connected to the third-stage heat exchanger through a gas pipeline, and the third-stage heat exchanger is connected to the third-stage centrifuge unit through a gas pipeline; the three-stage centrifuge devices are all equipped with an exhaust silencer and a vent valve.

2. According to claim 1, a high altitude negative pressure turbine simulation test bench exhaust system and method based on multi-stage series connection is characterized in that: The outlet of the turbine test section is connected to the exhaust volute, and the exhaust volute adopts a constant flow velocity design in aerodynamic design. The exhaust velocity inside the exhaust volute is ≤50m / s, and the cross-section of the exhaust volute flow channel is circular.

3. According to claim 1, a high altitude negative pressure turbine simulation test bench exhaust system and method based on multi-stage series connection is characterized in that: A second suction switch valve is provided on the gas pipeline branch at the outlet of the primary heat exchanger, and the second suction switch valve is connected to the inlet of the secondary heat exchanger.

4. An exhaust method based on the exhaust system of the multi-stage series-connected high-altitude negative pressure turbine simulation test bench as described in claims 1-3, comprising the following steps: S1, flow matching of centrifugal unit: the inlet flow quality of the unit , where is the inlet gas density, is the air intake speed, is the cross-sectional area of ​​the inlet pipe; then calculate the inlet flow volume , based on the flow-pressure ratio performance curve of the first-stage centrifugal unit, select the pressure ratio , where is the total inlet pressure of the centrifugal unit, is the total outlet pressure of the centrifugal unit; The export flow is ; According to the gas continuity equation , and the gas state equation , deduce the gas density after passing through the vacuum unit , and its corresponding flow volume is The exit speed is ; Heat exchangers are added between each stage to cool the compressed gas to , then the intake air mass of the next centrifugal unit is ; The pressure loss during the cooling process is , and the pressure loss of gas flow in the pipeline is , then the next stage intake pressure ratio is , based on the flow-pressure ratio performance curve of the two-stage centrifugal unit, select the pressure ratio Similarly, the flow rate of the last two stages is matched so that the outlet flow of the three-stage centrifugal unit meets the mass flow conservation law. At the same time, the total pressure ratio of the three-stage centrifugal device ,ensure , is standard atmospheric pressure; S2, obtain the centrifugal unit speed: according to the flow rate provided by the predetermined test conditions and negative pressure , combined with the centrifugal unit flow pressure ratio performance curve, and the pressure ratios of the first-stage centrifugal unit, the second-stage centrifugal unit, and the third-stage centrifugal unit are obtained respectively 、 、 , the corresponding speed is , , ; S3, negative pressure exhaust: close the atmospheric air supply main valve and auxiliary valve of the turbine adjustment to ensure that the air sucked by the centrifugal device enters the exhaust tower through its own vent valve; start the turbine vacuum machine inside the first-stage centrifugal unit, the second-stage centrifugal unit, and the third-stage centrifugal unit in sequence, open the built-in vent valve, fully exhaust the air through centrifugal exhaust, and adjust to the predetermined speed. , , ; Open the atmospheric air supply main valve for regulating the turbine intake, and gradually close the vent valve of the centrifugal device at the same time. Control the negative pressure state by adjusting the atmospheric air supply auxiliary valve and the frequency conversion control of the centrifugal device to generate a predetermined negative pressure at the outlet of the exhaust volute. The high-temperature gas is sucked through the negative pressure generated by the exhaust unit, and is gradually cooled down through the heat exchange device, and finally flows into the silencer tower for silencing and cooling treatment before being discharged into the atmosphere.

5. The method for the exhaust system of a multi-stage series-connected high-altitude negative pressure turbine simulation test bench as described in 4 is characterized in that: The second suction switch valve connects the gas discharged from the exhaust volute to the secondary centrifugal unit through the branch gas pipeline, and closes the first suction switch valve and the third suction switch valve.

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