阅读说明：本技术 基于滑动弧放电的超燃冲压发动机燃烧室测速装置及方法 (Sliding arc discharge-based speed measurement device and method for scramjet engine combustion chamber ) 是由 朱家健 冯戎 田轶夫 蔡尊 孙永超 王成龙 汪洪波 孙明波 于 2021-08-10 设计创作，主要内容包括：基于滑动弧放电的超燃冲压发动机燃烧室测速装置及方法,包括滑动弧等离子体测速装置,滑动弧等离子体测速装置安装在燃烧室的内壁面上,用于产生随燃烧室内气流的方向滑移的滑动弧等离子体；滑动弧等离子体作为气流速度的标示物,通过测量设定时间间隔内滑动弧等离子体的移动距离,确定滑动弧等离子体的滑移速度,进而根据滑动弧等离子体的滑移速度测得燃烧室内气流的速度。本发明的测速装置具有不干扰燃烧室内的流场结构、受环境温度干扰小、随流性好、不会对燃烧室造成污染、对高速气流测量准确性较好、适用于测量近壁面流速等优点。(The sliding arc discharge-based speed measuring device and method for the scramjet engine combustion chamber comprise a sliding arc plasma speed measuring device, wherein the sliding arc plasma speed measuring device is installed on the inner wall surface of the combustion chamber and used for generating sliding arc plasma which slides along the direction of air flow in the combustion chamber; and determining the slip speed of the sliding arc plasma by measuring the moving distance of the sliding arc plasma in a set time interval, and further measuring the speed of the airflow in the combustion chamber according to the slip speed of the sliding arc plasma. The speed measuring device has the advantages of no interference on a flow field structure in the combustion chamber, small interference by the ambient temperature, good flow following performance, no pollution to the combustion chamber, good high-speed airflow measuring accuracy, suitability for measuring the near-wall flow velocity and the like.)

1. Scramjet engine combustion chamber speed sensor based on slip arc is discharged, its characterized in that: the plasma velocity measurement device comprises a sliding arc plasma velocity measurement device, wherein the sliding arc plasma velocity measurement device is arranged on the inner wall surface of a combustion chamber;

the sliding arc plasma velocimeter comprises a cylindrical insulator, a first electrode, a second electrode and a power supply; the first electrode and the second electrode are symmetrically arranged on the top surface of the cylindrical insulator, the first electrode and the second electrode are both strip-shaped electrodes, the first electrode and the second electrode are obliquely and oppositely arranged, the first electrode is used as a high-voltage electrode, and the first electrode is connected with a power supply through a lead; the second electrode is used as a grounding electrode and is connected with the ground through a lead;

and starting a power supply, generating sliding arc plasma sliding along the direction of the airflow in the combustion chamber between the first electrode and the second electrode, taking the sliding arc plasma as a marker of the airflow speed, determining the sliding speed of the sliding arc plasma by measuring the moving distance of the sliding arc plasma in a set time interval, and further measuring the speed of the airflow in the combustion chamber according to the sliding speed of the sliding arc plasma.

2. The sliding arc discharge-based scramjet engine combustion chamber speed measurement device according to claim 1, wherein: a visual window is arranged on the side wall of the combustion chamber and is over against the sliding arc plasma speed measuring device in the combustion chamber; the high-speed camera is arranged on the outer side of the visual window and is used for shooting sliding arc plasma generated by the sliding arc plasma speed measuring device during working; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to two continuous images shot by the high-speed camera, determining the slip speed of the sliding arc plasma, and further measuring the speed of the airflow in the combustion chamber according to the slip speed of the sliding arc plasma.

3. The sliding arc discharge-based scramjet engine combustion chamber speed measurement device according to claim 1, wherein: the combustion chamber is characterized in that a mounting hole or a mounting groove for mounting the sliding arc plasma speed measuring device is formed in the lower metal wall surface of the combustion chamber, the sliding arc plasma speed measuring device is mounted on the lower metal wall surface of the combustion chamber, and the top surface of the cylindrical insulator is flush with the lower metal wall surface of the combustion chamber.

4. The sliding arc discharge based scramjet engine combustion chamber velocity measurement device according to any one of claims 1 to 3, wherein: the cylindrical insulator is sleeved with a cylindrical metal shell, and the metal shell is connected with the ground through a lead.

5. The sliding arc discharge-based scramjet engine combustion chamber speed measurement device according to claim 4, wherein: the first electrode and the second electrode are symmetrically distributed on the top surface of the cylindrical insulator.

6. The sliding arc discharge-based scramjet engine combustion chamber speed measurement device according to claim 5, wherein: the first end of the first electrode is opposite to the first end of the second electrode, and the distance between the first end of the first electrode and the first end of the second electrode is the shortest distance between the first electrode and the second electrode; the second end of the first electrode is opposite to the second end of the second electrode, and the distance between the second end of the first electrode and the second end of the second electrode is the longest distance between the first electrode and the second electrode;

the symmetry axis between the first electrode and the second electrode is parallel to the flow direction of the main flow of the combustion chamber, the shortest distance between the first electrode and the second electrode is close to the inlet of the combustion chamber, and the longest distance between the first electrode and the second electrode is far away from the inlet of the combustion chamber.

7. The sliding arc discharge-based scramjet engine combustion chamber speed measurement device according to claim 1, wherein: the first electrode and the second electrode are both strip-shaped tungsten electrodes.

8. The utility model provides a sliding arc plasma speed sensor which characterized in that: comprises a cylindrical insulator, a first electrode, a second electrode and a power supply; the first electrode and the second electrode are symmetrically arranged on the top surface of the cylindrical insulator, the first electrode and the second electrode are both strip-shaped electrodes, the first electrode and the second electrode are obliquely and oppositely arranged, the first electrode is used as a high-voltage electrode, and the first electrode is connected with a power supply through a lead; the second electrode is used as a grounding electrode and is connected with the ground through a lead;

the method comprises the steps of installing a sliding arc plasma speed measuring device in a flow field with speed measuring requirements, starting a power supply, generating sliding arc plasma which slides along the direction of air flow in the flow field between a first electrode and a second electrode, taking the sliding arc plasma as an indicator of air flow speed, determining the sliding speed of the sliding arc plasma by measuring the moving distance of the sliding arc plasma in a set time interval, and measuring the speed of the air flow in the flow field according to the sliding speed of the sliding arc plasma.

9. A sliding arc plasma velocimeter according to claim 8, wherein: shooting sliding arc plasma generated by the sliding arc plasma speed measuring device during working by using a high-speed camera; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to two continuous images shot by the high-speed camera, determining the slip speed of the sliding arc plasma, and further measuring the speed of the airflow in the flow field according to the slip speed of the sliding arc plasma.

10. The method for measuring the speed of the speed measuring device of the scramjet engine combustion chamber based on the sliding arc discharge of the claim 1, 2, 3, 5, 6 or 7 is characterized in that: starting a sliding arc plasma speed measuring device to generate sliding arc plasma which slides along the direction of the airflow in the combustion chamber; setting a shooting time interval of a high-speed camera, and shooting the sliding arc plasma by using the high-speed camera according to the set shooting time interval to obtain a continuous image; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to the two continuous images, obtaining the slip speed of the sliding arc plasma, and further measuring the speed of the airflow in the combustion chamber according to the slip speed of the sliding arc plasma.

Technical Field

The invention belongs to the technical field of scramjet engines, and particularly relates to a sliding arc discharge-based scramjet engine combustion chamber speed measuring device and method.

Background

At present, the main air velocity measuring equipment at home and abroad comprises methods such as a hot wire instrument, an intervention type measuring device, a PIV and the like.

For a hot wire instrument, the thermosensitive anemometer can heat the metal wire, when the temperature of the metal wire changes, the resistance value of the metal wire also changes, and then the voltage at two ends of the metal wire changes, the system can obtain the corresponding wind speed through measuring the voltage at two ends of the metal wire, and the wind measuring system is greatly influenced by the environment temperature and is easily interfered by the fluctuation of the environment temperature.

The intrusive measuring device is arranged in the flow field, affects the flow field and can be burnt by supersonic flame.

The PIV technology is essentially one of image analysis technologies, two pulse light sources with short time intervals are adopted to illuminate a flow field to be measured, a camera is used for recording tracer particles in the illuminated flow field, and a computer is used for carrying out image processing to obtain information of a velocity field. However, under hypersonic conditions, the flow-following properties of the tracer particles become poor and the tracer particles are difficult to spread into the wall or cavity areas, making the velocity of these areas difficult to measure. In addition, the trace particles can cause pollution to the scramjet engine, are difficult to clean, and can cause blockage of engine pipelines.

Disclosure of Invention

Aiming at the problem of measuring the flow velocity in the combustion chamber of the scramjet engine in the prior art, the invention provides a speed measuring device and method for the combustion chamber of the scramjet engine based on sliding arc discharge.

In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows:

the scramjet engine combustion chamber speed measuring device based on sliding arc discharge is arranged on the inner wall surface of a combustion chamber;

the sliding arc plasma velocimeter comprises a cylindrical insulator, a first electrode, a second electrode and a power supply; the first electrode and the second electrode are symmetrically arranged on the top surface of the cylindrical insulator, the first electrode and the second electrode are both strip-shaped electrodes, the first electrode and the second electrode are obliquely and oppositely arranged, the first electrode is used as a high-voltage electrode, and the first electrode is connected with a power supply through a lead; the second electrode is used as a grounding electrode and is connected with the ground through a lead;

and starting a power supply, generating sliding arc plasma sliding along the direction of the airflow in the combustion chamber between the first electrode and the second electrode, taking the sliding arc plasma as a marker of the airflow speed, determining the sliding speed of the sliding arc plasma by measuring the moving distance of the sliding arc plasma in a set time interval, and further measuring the speed of the airflow in the combustion chamber according to the sliding speed of the sliding arc plasma.

Specifically, a power supply is turned on, breakdown occurs at the shortest distance between a first electrode and a second electrode to generate sliding arc plasma, the sliding arc plasma slides along the electrodes along with the airflow under the action of the airflow, the sliding arc plasma serves as an indicator of the airflow speed, the sliding speed of the sliding arc plasma is determined by measuring the moving distance of the sliding arc plasma in a set time interval, and the speed of the airflow in the combustion chamber is further measured according to the sliding speed of the sliding arc plasma.

Further, as a preferred scheme of the invention, a visual window is arranged on the side wall of the combustion chamber, and the visual window is over against the sliding arc plasma speed measuring device in the combustion chamber; the high-speed camera is arranged on the outer side of the visual window and is used for shooting sliding arc plasma generated by the sliding arc plasma speed measuring device during working; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to two continuous images shot by the high-speed camera, determining the slip speed of the sliding arc plasma, and further measuring the speed of the airflow in the combustion chamber according to the slip speed of the sliding arc plasma.

Further, as a preferable aspect of the present invention, a mounting hole or a mounting groove for mounting the sliding arc plasma velocity measuring device is provided on the lower metal wall surface of the combustion chamber, the sliding arc plasma velocity measuring device is mounted on the lower metal wall surface of the combustion chamber, and the top surface of the cylindrical insulator is flush with the lower metal wall surface of the combustion chamber.

Further, as a preferable mode of the present invention, a cylindrical metal shell is fitted around the cylindrical insulator, and the metal shell is connected to the ground through a lead wire.

Further, as a preferable aspect of the present invention, the first electrode and the second electrode are symmetrically distributed on the top surface of the cylindrical insulator.

Further, as a preferable aspect of the present invention, the first end of the first electrode and the first end of the second electrode are opposed to each other, and a distance between the first end of the first electrode and the first end of the second electrode is a shortest distance between the first electrode and the second electrode; the second end of the first electrode is opposite to the second end of the second electrode, and the distance between the second end of the first electrode and the second end of the second electrode is the longest distance between the first electrode and the second electrode;

the symmetry axis between the first electrode and the second electrode is parallel to the flow direction of the main flow of the combustion chamber, the shortest distance between the first electrode and the second electrode is close to the inlet of the combustion chamber, and the longest distance between the first electrode and the second electrode is far away from the inlet of the combustion chamber.

Further, as a preferable aspect of the present invention, the first electrode and the second electrode are both strip-shaped tungsten electrodes.

The invention provides a sliding arc plasma speed measuring device which can be applied to speed measurement in various flow fields and is not limited to a combustion chamber. The sliding arc plasma speed measuring device comprises a cylindrical insulator, a first electrode, a second electrode and a power supply; the first electrode and the second electrode are symmetrically arranged on the top surface of the cylindrical insulator, the first electrode and the second electrode are both strip-shaped electrodes, the first electrode and the second electrode are obliquely and oppositely arranged, the first electrode is used as a high-voltage electrode, and the first electrode is connected with a power supply through a lead; the second electrode is used as a grounding electrode and is connected with the ground through a lead;

the method comprises the steps of installing a sliding arc plasma speed measuring device in a flow field with speed measuring requirements, starting a power supply, generating sliding arc plasma which slides along the direction of air flow in the flow field between a first electrode and a second electrode, taking the sliding arc plasma as an indicator of air flow speed, determining the sliding speed of the sliding arc plasma by measuring the moving distance of the sliding arc plasma in a set time interval, and measuring the speed of the air flow in the flow field according to the sliding speed of the sliding arc plasma.

Furthermore, the high-speed camera can be used for shooting the sliding arc plasma generated by the sliding arc plasma speed measuring device during working; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to two continuous images shot by the high-speed camera, determining the slip speed of the sliding arc plasma, and further measuring the speed of the airflow in the flow field according to the slip speed of the sliding arc plasma.

The invention provides a speed measuring method by utilizing the speed measuring device of the scramjet engine combustion chamber based on sliding arc discharge, which comprises the following steps of:

starting a sliding arc plasma speed measuring device to generate sliding arc plasma which slides along the direction of the airflow in the combustion chamber;

setting a shooting time interval of a high-speed camera, and shooting the sliding arc plasma by using the high-speed camera according to the set shooting time interval to obtain a continuous image; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to the two continuous images, obtaining the slip speed of the sliding arc plasma, and further measuring the speed of the airflow in the combustion chamber according to the slip speed of the sliding arc plasma.

The method for acquiring the slip speed of the sliding arc plasma comprises the following steps: setting a shooting time interval delta t of a high-speed camera, utilizing two continuous images obtained by shooting of the high-speed camera to calculate the moving distance d of the sliding arc plasma in the two continuous images, and further obtaining the slip velocity v of the sliding arc plasma_s＝d/Δt。

The accurate measurement of the flow velocity in the combustion chamber of the scramjet engine has very important significance for calibrating inflow parameters, researching the thickness of a boundary layer, disclosing the interaction mechanism of combustion and turbulence and the like. The invention provides a sliding arc discharge-based speed measuring device and method for a combustion chamber of a scramjet engine, and solves the problem of measuring the flow speed in the combustion chamber of the scramjet engine. Through the technical scheme, the invention has the following beneficial technical effects:

the sliding arc plasma in the combustion chamber of the scramjet engine is used as the marker of the air flow speed, the sliding arc plasma has good flow following performance, and the moving distance of the sliding arc plasma in a set time interval is shot by a high-speed camera to obtain the air flow speed in the combustion chamber. When a power supply is turned on and the sliding arc plasma speed measuring device works, breakdown occurs at the shortest distance between the two strip-shaped tungsten electrodes to generate sliding arc plasma, the sliding arc plasma slides along the length direction of the two electrodes along with the airflow direction, the sliding arc plasma is used as a marker of the airflow speed, the moving distance of the sliding arc plasma in a set time interval is shot by a high-speed camera, and the speed of the airflow in the combustion chamber is obtained. The set time interval is the time difference between two continuous images, namely the preset shooting time interval of the high-speed camera. The moving distance of the sliding arc plasma is the sliding distance of the sliding arc plasma blown by the airflow in the combustion chamber, and can be obtained through two continuous images. The speed measuring device has the advantages of no interference on a flow field structure in the combustion chamber, small interference by the ambient temperature, good flow following performance, no pollution to the combustion chamber, good high-speed airflow measuring accuracy, suitability for measuring the near-wall flow velocity and the like.

Drawings

Fig. 1 is a schematic perspective view of a sliding arc plasma velocity measurement device according to an embodiment of the present invention;

FIG. 2 is a top view of a sliding arc plasma velocimeter according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a sliding arc plasma velocity measurement device according to an embodiment of the present invention;

FIG. 4 is a schematic view of an installation structure of a sliding arc plasma velocity measurement device in a combustion chamber according to an embodiment of the present invention;

FIG. 5 is a schematic diagram illustrating a slip velocity distribution of a sliding arc plasma under supersonic jet in an embodiment of the present invention;

reference numbers in the figures:

1. a cylindrical insulator; 2. a first electrode; 3. a second electrode; 4. a power source; 5. the earth; 6. a metal housing; 7. the shortest distance between the first electrode and the second electrode; 8. the longest distance between the first electrode and the second electrode; 9. a lower metal wall of the combustion chamber; 10. a sliding arc plasma.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings. It should be noted that, in the drawings or the description, the undescribed contents and parts of english are abbreviated as those well known to those skilled in the art. Some specific parameters given in the present embodiment are merely exemplary, and the values may be changed to appropriate values accordingly in different embodiments.

The main idea of the invention is to measure the flow field velocity by using the discharge characteristic of the sliding arc plasma. Referring to fig. 1, 2 and 3, the present invention provides a sliding arc plasma velocimeter comprising a cylindrical insulator 1, a first electrode 2, a second electrode 3 and a power supply 4. The cylindrical insulator 1 in this embodiment is a cylindrical ceramic insulator. The diameter of the cylindrical insulator 1 is 36 mm. The first electrode 2 and the second electrode 3 are symmetrically arranged on the top surface of the cylindrical insulator 1, the first electrode 2 and the second electrode 3 are both strip-shaped electrodes, the first electrode 2 and the second electrode 3 are obliquely and oppositely arranged, the first electrode 2 is used as a high-voltage electrode, and the first electrode 2 is connected with a power supply 4 through a lead; the second electrode 3 serves as a ground electrode, and the second electrode 3 is connected to the ground 5 through a wire. The cylindrical insulator 1 is sleeved with a cylindrical metal shell 6, and the metal shell 6 is connected with the ground 5 through a lead.

The first end of the first electrode 2 is opposite to the first end of the second electrode 3, and the distance between the first end of the first electrode 2 and the first end of the second electrode 3 is the shortest distance between the first electrode 2 and the second electrode 3; the second end of the first electrode 2 is opposite to the second end of the second electrode 3, and the distance between the second end of the first electrode 2 and the second end of the second electrode 3 is the longest distance between the first electrode 2 and the second electrode 3. In this embodiment, the shortest distance between the first electrode 2 and the second electrode 3 is 2mm, the longest distance between the first electrode 2 and the second electrode 3 is 7mm, and the first electrode 2 and the second electrode 3 are both strip-shaped tungsten electrodes and have a length of 15.8 mm.

When the sliding arc plasma speed measuring device is used for measuring speed, the sliding arc plasma speed measuring device is installed in a flow field with a speed measuring requirement. The symmetry axis between the first electrode 2 and the second electrode 3 is parallel to the flowing direction of the airflow in the flow field, the shortest distance 7 between the first electrode and the second electrode is close to the airflow inlet, and the longest distance 8 between the first electrode and the second electrode is far away from the airflow inlet.

And (3) starting a power supply 4, breaking down at one end of the shortest distance between the first electrode 2 and the second electrode 3 to generate a sliding arc plasma 10, wherein the sliding arc plasma 10 slides to one end of the longest distance along the electrodes under the action of the airflow, the sliding arc plasma 10 is used as an indicator of the airflow speed, the sliding speed of the sliding arc plasma is determined by measuring the moving distance of the sliding arc plasma 10 in a set time interval, and the speed of the airflow in the flow field is further measured according to the sliding speed of the sliding arc plasma. Specifically, a high-speed camera can be used for shooting the motion process of the sliding arc plasma according to a set shooting time interval to obtain a continuous image; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to the two continuous images, obtaining the slip speed of the sliding arc plasma, and further measuring the speed of the airflow in the flow field according to the slip speed of the sliding arc plasma.

Referring to fig. 4, an embodiment of the present invention provides a sliding arc discharge-based scramjet engine combustion chamber velocity measurement device, including a sliding arc plasma velocity measurement device, where the structure of the sliding arc plasma velocity measurement device is shown in fig. 1, fig. 2, and fig. 3, and is not described herein again. The cylindrical insulator 1 in this embodiment is a cylindrical ceramic insulator. The diameter of the cylindrical insulator 1 is 36 mm.

The sliding arc plasma speed measuring device is arranged in the combustion chamber. Specifically, the lower metal wall surface 9 of the combustion chamber is provided with a mounting hole or a mounting groove for mounting the sliding arc plasma velocity measurement device, the sliding arc plasma velocity measurement device is mounted on the lower metal wall surface 9 of the combustion chamber, and the top surface of the cylindrical insulator of the sliding arc plasma velocity measurement device is flush with the lower metal wall surface 9 of the combustion chamber.

Specifically, the power supply is turned on, breakdown occurs at the shortest distance between the first electrode 2 and the second electrode 3, sliding arc plasma is generated, the sliding arc plasma is used as a marker of the gas flow speed along with the sliding of the gas flow along the electrodes under the action of the gas flow, and the gas flow speed can be obtained by measuring the moving distance of the sliding arc plasma in a set time interval.

In fig. 4, the first electrode 2 and the second electrode 3 are both strip-shaped tungsten electrodes, the shortest distance between the first electrode 2 and the second electrode 3 is 2mm, the largest distance is 7mm, and the lengths of the first electrode 2 and the second electrode 3 are both 15.8 mm. In order to ensure that no creepage occurs during discharge in the combustion chamber, the distance between the first electrode 2 and the second electrode 3, which has the longest distance, is 31mm from the metal casing.

In fig. 4, the axis of symmetry between the first electrode 2 and the second electrode 3 is parallel to the flow direction of the main stream of the combustion chamber, the shortest distance between the first electrode 2 and the second electrode 3 is close to the inlet of the combustion chamber, and the longest distance between the first electrode 2 and the second electrode 3 is far from the inlet of the combustion chamber. When the sliding arc plasma speed measuring device discharges in the combustion chamber, the shortest distance between the first electrode 2 and the second electrode 3 faces to the inlet of the combustion chamber. The sliding arc plasma breaks down at the shortest distance between the first electrode 2 and the second electrode 3, then slides forwards along the electrodes along with the direction of airflow of the combustion chamber, the length of the sliding arc plasma is gradually stretched until the maximum power of the power supply is reached, then the sliding arc plasma disappears, and the new sliding arc plasma breaks down again at the shortest distance between the first electrode 2 and the second electrode 3, which is regarded as a sliding arc discharge period.

In one embodiment of the invention, during the sliding arc discharge process, a high-speed camera is used for shooting the sliding arc motion process, and the current and voltage data of the sliding arc plasma are measured at the same time. The shooting frequency of the high-speed camera is set to be higher than 80000Hz so as to better acquire the dynamic development process of the sliding arc. And extracting the bone structure of the sliding arc plasma from the shot images, calculating the moving distance of the sliding arc plasma in the two continuous images to obtain the slip speed of the sliding arc plasma, and measuring the speed of the airflow in the combustion chamber according to the slip speed of the sliding arc plasma. The accuracy of flow velocity measurement can be obviously improved. The plasma discharge device is positioned below the flow field, so that the flow field is not interfered, and the slip speed of the sliding arc plasma is not greatly influenced by the temperature, so that the measurement can be carried out in a high-temperature environment, and the pollution to a combustion chamber is avoided.

In one embodiment of the invention, the side wall of the combustion chamber is provided with a visual window, and the visual window is over against the sliding arc plasma speed measuring device in the combustion chamber; the high-speed camera is arranged on the outer side of the visual window and is used for shooting sliding arc plasma generated by the sliding arc plasma speed measuring device during working; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to two continuous images shot by the high-speed camera, determining the slip speed of the sliding arc plasma, and further measuring the speed of the airflow in the combustion chamber according to the slip speed of the sliding arc plasma.

In an embodiment of the present invention, a method for measuring a speed of a scramjet engine combustion chamber speed measuring device based on sliding arc discharge includes:

starting a sliding arc plasma speed measuring device, breaking down at the shortest distance between the first electrode 2 and the second electrode 3 to generate a sliding arc plasma 8, and sliding the sliding arc plasma 8 along with the airflow to the longest distance between the first electrode 2 and the second electrode 3 along the electrodes under the action of the airflow;

setting a shooting time interval of a high-speed camera, and shooting the sliding arc plasma by using the high-speed camera according to the set shooting time interval to obtain a continuous image; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to the two continuous images, obtaining the slip speed of the sliding arc plasma, and further measuring the speed of the airflow in the combustion chamber according to the slip speed of the sliding arc plasma.

The method for acquiring the slip speed of the sliding arc plasma comprises the following steps: setting a shooting time interval delta t of a high-speed camera, utilizing two continuous images obtained by shooting of the high-speed camera to calculate the moving distance d of the sliding arc plasma in the two continuous images, and further obtaining the slip velocity v of the sliding arc plasma_s＝d/Δt。

Experiments and simulation verification show that in the embodiment of the invention, the air flow velocity of the supersonic jet is estimated by using the sliding arc plasma velocity measurement device, and the velocity distribution calculated by using the large vortex simulation is used for calibration. The slip speed of the slip arc plasma is close to the local flow speed, and the error is less than 5%. To obtain a supersonic jet (Ma ═ 1.2), a laval nozzle with a diameter of 1.5mm was inserted in the central tube. Two electrodes in the sliding arc plasma speed measuring device are strip tungsten needle electrodes with the diameter of 1 mm. The sliding arc plasma speed measuring device is arranged above the Laval nozzle. Two electrodes in the sliding arc plasma speed measuring device are symmetrically arranged by taking the center of the outlet of the spray pipe as a central point. One of the electrodes is connected to a plasma power supply and serves as an anode, while the other is grounded as a cathode. The minimum spacing between the two electrodes in a sliding arc plasma tachometer is 1.27 mm. Shooting sliding arc plasma generated by the sliding arc plasma speed measuring device during working by using a high-speed camera; and obtaining the moving distance of the sliding arc plasma in the shooting time interval according to two continuous images shot by the high-speed camera, determining the slip speed of the sliding arc plasma, and further measuring the outlet speed of the airflow passing through the Laval nozzle according to the slip speed of the sliding arc plasma. The outlet speed of the Laval nozzle is 367m/s after measurement. The discharge pattern of the sliding arc is photographed by a high-speed camera. The camera frame rate was set to 224kHz and the exposure time was 2.9 μ s.

The slip velocity of the slip arc can be obtained by calculating the slip distance of the slip arc plasma in two consecutive slip arc discharge images taken by a high-speed camera, as shown in fig. 4, the black solid line represents the bone structure of the slip arc plasma, and the black dotted line represents the electrode. The slip velocity of the sliding arc plasma near the initial breakdown position can reach 354 m/s. Through large vortex simulation, the velocity distribution of supersonic jet can be obtained, and the average velocity of the airflow near the initial breakdown position of the sliding arc plasma is 344 m/s. This is more consistent with the calculated slip arc plasma slip velocity, indicating that the slip arc plasma slip velocity can be used as a data basis for estimating the gas flow velocity.

The foregoing description of the preferred embodiments of the present invention has been included to describe the features of the invention in detail, and is not intended to limit the inventive concepts to the particular forms of the embodiments described, as other modifications and variations within the spirit of the inventive concepts will be protected by this patent. The subject matter of the present disclosure is defined by the claims, not by the detailed description of the embodiments.