A low-pressure ejector device used in a Martian wind tunnel

Abstract

The purpose of the present invention is to provide a low-pressure ejector device for use in a Martian wind tunnel, comprising an ejector housing, an ejector chamber housing, an ejector chamber, a plurality of nozzles and an air supply pipeline, wherein the air supply pipeline is connected to an air source, the ejector chamber housing surrounds the ejector housing, and is sealed and connected to its outer wall to form a closed ejector chamber, the air supply pipeline is connected to the ejector chamber, a plurality of nozzles are parallel to each other and radially pass through the ejector housing at a certain interval, the head and tail of each nozzle are respectively connected to the ejector chamber, and a plurality of nozzles are provided in the portion of each nozzle located inside the ejector housing. Compared with the ejector of a conventional wind tunnel, the ejector efficiency of the present device is extremely high, and the ejector consumes a large amount of gas to form the same wind speed, while the conventional ejector consumes a large amount of gas, while the ejector consumes very little gas, making it possible to continuously form wind speed for a long time, and significantly improving the maximum wind speed.

Description

Technical Field

[0001] The invention relates to a low-pressure ejector device applied to a Martian wind tunnel. Background Art

[0002] The driving system of the normal pressure low-speed wind tunnel is powered by a controllable motor and a fan driven by it. Another type of temporary high-speed wind tunnel uses a compressor to pressurize the air and store it in an air storage tank, or uses a vacuum pump to evacuate the vacuum tank connected to the wind tunnel outlet pipe. During the experiment, the valve is opened quickly to allow high-pressure air to enter the cave directly or through an ejector, or the air is sucked into the cave by the vacuum tank. Therefore, there are various forms of blowing, ejection, suction and their combination. Generally, the Reynolds number is high, and its working time can be from a few seconds to tens of seconds.

[0003] As for the driving system of the Mars wind tunnel, its power driving system must meet the following technical indicators: the gas medium of the test can be either CO 2 It can also be air. The pressure of the test chamber is a low-pressure environment of 100-1500Pa. The wind speed range of the test section is 5-100m / s, and the wind speed can be continuously adjusted. In addition, the continuous blowing test needs to be more than 1 hour.

[0004] Traditional ejectors have a relatively thick nozzle throat diameter, high air supply pressure, and large gas consumption, which can form a high Mach number at the nozzle outlet. Under the action of the ejector, a very high wind speed is formed in the test area. However, the air pressure in the Martian wind tunnel is extremely low, the gas density is also extremely low, and the temperature is also relatively low. The use of traditional ejectors not only cannot form high wind speeds, but the jet airflow is prone to freezing instantly, and the throat of the ejector is blocked, reducing the efficiency of the ejector. In a vacuum container with low air pressure (100-1500Pa), simply increasing the intake pressure of a conventional ejector can no longer achieve high wind speeds. The maximum wind speed in the test section is only about 70m / s, and it is not possible to conduct continuous tests for a long time. Summary of the invention

[0005] Based on the above shortcomings, the present invention discloses a low-pressure ejector device applied to a Mars wind tunnel, which is located in the ejector section of the Mars wind tunnel. The ejector section is located behind the test section in the direction of the airflow. It can obtain high wind speed under low pressure, consumes little gas, and can work continuously for more than 1 hour, while solving the icing problem caused by the instantaneous jet airflow.

[0006] The technology adopted by the present invention is as follows: a low-pressure ejector device used in a Martian wind tunnel, comprising an ejector shell, an ejector chamber shell, an ejector chamber, a plurality of nozzles and an air supply pipeline, the air supply pipeline being connected to an air source, the ejector chamber shell surrounding the ejector shell and being sealed with its outer wall to form a closed ejector chamber, the air supply pipeline being connected to the ejector chamber, a plurality of nozzles being parallel to each other and radially passing through the ejector shell at certain intervals, the head and tail of each nozzle being respectively connected to the ejector chamber, and a plurality of nozzles being provided at the portion of each nozzle located inside the ejector shell.

[0007] The present invention also has the following technical features:

[0008] 1. The nozzle is a conical throat with a straight tube, and the throat diameter of the straight tube on the throat cannot be greater than 1 / 10 of the inner diameter of the nozzle.

[0009] 2. The multiple nozzles on each of the nozzles are distributed at equal intervals.

[0010] 3. The number of nozzles on each of the nozzles is the same as the number of nozzles.

[0011] 4. A pipeline heater is installed on the gas supply pipeline.

[0012] 5. A flow regulating valve is installed on the gas supply pipeline.

[0013] The advantages and beneficial effects of the present invention are as follows: compared with existing devices of the same type, this ejector consumes very little gas to form a same wind speed, can form a continuous wind speed for a long time, and has a high ejection efficiency; in a vacuum container with low air pressure (100-1500Pa), the maximum wind speed can be significantly increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a main structural diagram of a low-pressure ejector device used in a Martian wind tunnel.

[0015] Figure 2 This is a left view of the structure of a low-pressure ejector device used in a Martian wind tunnel.

[0016] Figure 3 This is a nozzle diagram of a low-pressure ejector device used in a Martian wind tunnel.

[0017] Figure 4 This is a schematic diagram of the air supply pipeline of a low-pressure ejector device used in a Martian wind tunnel.

[0018] In the figure: 1. ejector section connecting flange, 2. ejector section outer shell, 3. ejector chamber outer shell, 4. nozzle, 5. connecting bolts, 6. ejector chamber, 7. air inlet connecting flange, 8. bellows, 9. air supply pipeline, 10. ejector section bracket, 11. throat, 12. flow meter, 13. flow regulating valve, 14. pressure gauge, 15. pressure regulating valve, 16. pipeline heater, 17. safety valve, 18. ball valve, 19. air inlet pipeline, 20. vacuum container, 21. Mars wind tunnel stabilization section, 22. wind tunnel test section, 23. ejector section. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] Example 1

[0021] like Figure 1-4As shown, a low-pressure ejector device applied to a Martian wind tunnel comprises an ejector housing 2, an ejector chamber shell 3, an ejector chamber 6, a plurality of nozzles 4 and an air supply pipeline 9, wherein the air supply pipeline 9 is connected to an air source, the ejector chamber shell 3 surrounds the ejector housing 2 and is sealed with its outer wall to form a closed ejector chamber 6, the air supply pipeline 9 is connected to the ejector chamber 6, a plurality of nozzles 4 are parallel to each other and radially penetrate the ejector housing 2 at a certain interval, the head and tail of each nozzle 4 are respectively connected to the ejector chamber 6, and a plurality of nozzles 11 are opened on the part of each nozzle 4 located inside the ejector housing 2. The nozzle 11 is a conical throat with a straight tube. The throat adopts a 45-degree diffusion mode, which can obtain high wind speed under low pressure, consume less gas, and will not freeze at the nozzle. It can work continuously for more than 1 hour. The throat diameter of the straight tube on the throat cannot be greater than 1 / 10 of the inner diameter of the nozzle 4. The multiple nozzles 11 on each nozzle are evenly spaced. The number of nozzles on each nozzle is the same as the number of nozzles. The Mars wind tunnel is placed in a vacuum container 20. The gas pressure in the vacuum container 20 is 100-1500Pa. The gas pressure in the ejector chamber 6 is relatively high, about 0.02mPa to 0.3mPa. The airflow enters the nozzle 4 from the ejector chamber 6 and finally ejects from the nozzle. Due to the special structure of the nozzle, the airflow first flows through the narrow straight tube throat, and then quickly diffuses at a cone angle, which not only enables the airflow to obtain a higher Mach number, but also can be more evenly distributed throughout the ejector section 23. The nozzle orifice of the nozzle 11 is very narrow, so even if the air pressure in the ejector chamber 6 is very high, the flow rate of the ejected air flow can still be very low. The low gas flow rate can make it easier to maintain the air pressure in the vacuum container 20 without consuming too much air extraction of the vacuum unit, so that the ejector can work continuously for a long time. The nozzle can be made of stainless steel, copper or other metal materials. The flow meter 12, flow regulating valve 13, pressure gauge 14, pressure regulating valve 15, pipeline heater 16, safety valve 17 and ball valve 18 are installed on the gas supply pipeline 9 in sequence. The gas medium required for the test enters the gas supply pipeline 9 from the air inlet pipeline 19 outside the vacuum container, and then enters the ejector chamber, and finally reaches the nozzle 4 connected to the ejector chamber, and is discharged from the throat 11 on the nozzle 4. The pipeline heater 16 should be placed as close to the outer container of the Mars wind tunnel as possible. The gas medium required for the test is stored in the buffer tank. The ejector outer shell is connected to the front and rear diffusers of the ejector through front and rear flanges respectively. Since the cross section of the wind tunnel is a square, the cross section of the ejector outer shell is also a square, and the inner dimensions are consistent with the inner dimensions of the wind tunnel cross section.

[0022] Example 2

[0023] Combination Figure 4A low-pressure ejector device used in a Martian wind tunnel includes an ejector housing 2, an ejector chamber housing 3, an ejector chamber 6, a plurality of nozzles 4 and an air supply line 9. The air supply line 9 is connected to the air source. The ejector chamber housing 3 surrounds the ejector housing 2 and is sealed to its outer wall to form a closed ejector chamber 6. The air supply line 9 is connected to the ejector chamber 6. The plurality of nozzles 4 are parallel to each other and radially pass through the ejector housing 2 at a certain interval. The head and tail of each nozzle 4 are respectively connected to the ejector chamber 6. A plurality of nozzles 11 are opened on the part of each nozzle 4 located inside the ejector housing 2. The air source of the ejector device is stored in a buffer tank and introduced through an air intake pipe 19. CO 2 The gas is output from the buffer tank through the air inlet pipe 19, the ball valve 18, the pipe heater 16, the pressure regulating valve 15, the pressure gauge 14, the flow regulating valve 13, the flow meter 12, and finally enters the air supply pipe 9 inside the vacuum container 20. The ball valve 18 acts as a switch, and the pipe heater 16 is a power-adjustable heating device that can heat the CO in the gas pipeline. 2 The gas is prevented from being too cold before entering the ejector section 23, which may cause icing due to long-term ejection. The function of the pressure regulating valve 15 is to initially reduce the gas supply pressure and stabilize it at a specified pressure value. The function of the flow regulating valve 13 is to accurately adjust the gas supply pressure to control the wind speed in the wind tunnel test section.

[0024] The device can achieve low wind speed by lowering the flow regulating valve 13 on the air supply pipe 19, so that the flow entering the air supply pipe is less, and the pressure sprayed from the nozzle is correspondingly reduced, and the derived injection gas flow is reduced, but the airflow uniformity can still be guaranteed.

Claims

1. A low-pressure ejector device for use in a Martian wind tunnel, comprising an ejector housing (2), an ejector chamber housing (3), an ejector chamber (6), a plurality of nozzles (4) and an air supply pipeline (9), wherein the air supply pipeline (9) is connected to an air source, and is characterized in that: The ejector chamber shell (3) surrounds the ejector shell (2) and is sealed with its outer wall to form a closed ejector chamber (6). The air supply pipeline (9) is connected to the ejector chamber (6). A plurality of nozzles (4) are parallel to each other and radially penetrate the ejector shell (2) at a certain interval. The head and tail of each nozzle (4) are respectively connected to the ejector chamber (6). A plurality of nozzles (11) are opened on the part of each nozzle (4) located inside the ejector shell (2); the nozzle (11) is a conical throat hole with a straight tube, and the throat diameter of the straight tube on the throat hole cannot be greater than 1 / 10 of the inner diameter of the nozzle (4); the plurality of nozzles (11) on each nozzle are evenly spaced; the number of nozzles on each nozzle is the same as the number of nozzles.

2. A low pressure ejector device for use in a Martian wind tunnel according to claim 1, characterized in that: A pipeline heater (16) is installed on the gas supply pipeline (9).

3. A low pressure ejector device for use in a Martian wind tunnel according to claim 1 or 2, characterized in that: A flow regulating valve (13) is installed on the gas supply pipeline (9).

Images