CN110044578B - A Pitot Tube Device for Pressure Pulsation Measurement in Hypersonic Wind Tunnels - Google Patents

Abstract

The invention discloses a pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel, belonging to the field of fluid mechanics. The pitot tube device comprises a main body and a sensor, the sensor is located in the hollow inner cavity of the main body, and the material of the main body is porous Metal materials; porous materials have microporous gaps, which can partially absorb the perturbation waves such as acoustic waves, vortex waves and entropy waves without destroying the flow field structure. When the pitot tube device is used for the measurement of pressure pulsation in a hypersonic wind tunnel, the main body composed of the porous metal material absorbs the flow field disturbance, weakens the reflection oscillation of the flow field disturbance between the shock surface and the front end of the pitot tube device, thereby improving the hypersonic speed. Accuracy of wind tunnel pressure pulsation measurements. Thereby, the technical problem that the existing pitot tube is used to measure the pressure pulsation of the hypersonic wind tunnel has a large error.

Description

A Pitot Tube Device for Pressure Pulsation Measurement in Hypersonic Wind Tunnels

technical field

The invention belongs to the field of fluid mechanics, and more particularly relates to a pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel.

Background technique

At present, the main ground experimental research platform for hypersonic aerodynamics research is the hypersonic wind tunnel. After the construction of a conventional hypersonic wind tunnel is completed, the static and dynamic quality of the flow field must be identified, where the dynamic quality refers to the modal characteristics of free flow disturbance. At present, the quantitative calibration of disturbance modal characteristics is commonly used in the three quantities of pressure pulsation, density pulsation, total temperature pulsation, venous temperature pulsation and velocity pulsation of free flow in the wind tunnel. The pressure pulsation is currently measured by a pitot tube. Pitot tubes have the advantages of being durable, simple and easy to operate, and are widely used in the measurement of pressure and pressure pulsation in hypersonic experiments. In hypersonic airflow, a bow shock is formed near the front end of the pitot tube. The data measured by the pitot tube is the total pressure of the flow after the shock wave and its pulsation. Therefore, the pitot data needs to be converted into the pressure and its pulsation in free flow through the transfer function. Since the development law and mechanism of the pulsation in the free flow after passing through the shock wave are still unknown, it is more accurate to use the results of direct numerical simulation to fit the transfer function. Through direct numerical simulation, it can be found that the amount of pulsation in the free flow will reflect back and forth between the shock surface and the front surface of the pitot tube to form oscillation, resulting in a large error in the pitot data system. Especially due to the resonance effect, the error of the pressure pulsation amount measured by the pitot tube around the resonance frequency will be larger.

It can be seen that there is a large error when the existing pitot tube is used to measure the pressure pulsation of the hypersonic wind tunnel.

SUMMARY OF THE INVENTION

In view of the above defects or improvement needs of the prior art, the present invention provides a pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel, thereby solving the problem when the existing pitot tube is used to measure the pressure pulsation in a hypersonic wind tunnel There are technical problems with large errors.

In order to achieve the above object, the present invention provides a pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel, comprising a main body and a sensor, the sensor is located in the hollow inner cavity of the main body, and the material of the main body is a porous metal material;

When the pitot tube device is used for the measurement of pressure pulsation in a hypersonic wind tunnel, the main body composed of the porous metal material absorbs the flow field disturbance and weakens the reflection oscillation of the flow field disturbance between the shock surface and the front face of the pitot tube device, thereby improving the measurement performance. accuracy.

Further, the pore diameter of the porous metal material is 0.05mm˜0.2mm.

Further, the porosity of the porous metal material is 50% to 96%.

Further, the permeability of the porous metal material is 1×10 ^-9 m ² to 1×10 ^-5 m ² .

Further, the pitot tube device further includes a connecting piece, the connecting piece is located in the hollow inner cavity of the main body, the sensor is located in the hollow inner cavity of the connecting piece, and the connecting piece is used for fixing the sensor.

Further, the hollow inner cavity of the connector includes a first section and a second section, the first section is used for fixing the sensor, and the second section is a hollow hole structure, which is used for fixing the tail cable of the sensor.

Further, the connector, the main body and the sensor are on the same central axis.

In general, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

(1) A solid metal body is usually used in the existing pitot tube, which will cause total reflection to the disturbance in the supersonic free flow, which will affect the accuracy of the measurement result. Porous materials have microporous gaps, which can partially absorb the perturbation waves such as acoustic waves, vortex waves and entropy waves without destroying the flow field structure. When the pitot tube device is used for the measurement of pressure pulsation in a hypersonic wind tunnel, the main body composed of the porous metal material absorbs the flow field disturbance, weakens the reflection oscillation of the flow field disturbance between the shock surface and the front end of the pitot tube device, thereby improving the hypersonic speed. Accuracy of wind tunnel pressure pulsation measurements. Thereby, the technical problem that the existing pitot tube is used to measure the pressure pulsation of the hypersonic wind tunnel is solved.

(2) The use of porous metal materials in pitot tubes to measure the pressure pulsation in hypersonic incoming flow can eliminate the influence of part of the incoming flow disturbance. The technical problem is that porous metal materials with different properties, such as permeability, porosity, etc., The corrections to the experimental measurements are different, but the overall trend is a good trend compared to conventional metal solid body pitot tubes. In order to overcome the above difficulties, the present invention conducts a series of parameter research through a hypersonic wind tunnel test to determine the parameter range of the porous metal material that can effectively improve the reliability of the experimental data. The pore size range of the porous metal material depends on the size of the pitot tube probe. For a conventional-sized pitot tube probe, the pore diameter of the porous metal material is 0.05mm to 0.2mm, the porosity of the porous metal material is 50% to 96%, and the permeability of the porous metal material is 1×10 ^-9 m ² to 1× 10 ^-5 m ² . Appropriate parameter selection has a good effect on eliminating the sonic disturbance between the pitot tube probe and the out-of-body shock wave, and can improve the accuracy of the pitot tube's measurement results in hypersonic flow fields.

Description of drawings

1 is a schematic structural diagram of a pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel according to Embodiment 1 of the present invention;

2 is an exploded view of a Pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel according to Embodiment 1 of the present invention;

3 is a component assembly diagram of a pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel according to Embodiment 1 of the present invention;

4 is a schematic structural diagram of a pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel according to Embodiment 2 of the present invention;

Throughout the drawings, the same reference numbers are used to refer to the same elements or structures, wherein:

1 is the main body, 11 is the front section of the main body, 12 is the rear section of the main body, 2 is the sensor, 3 is the connecting piece, 4 is the central axis, 5 is the front plane, 6 is the cylindrical shoulder, 7 is the transition fillet, and 8 is the pitot tube device.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

A pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel, comprising a main body and a sensor, wherein the sensor is located in a hollow inner cavity of the main body, and the material of the main body is a porous metal material;

When the pitot tube device is used for the measurement of pressure pulsation in a hypersonic wind tunnel, the main body composed of the porous metal material absorbs the flow field disturbance and weakens the reflection oscillation of the flow field disturbance between the shock surface and the front face of the pitot tube device, thereby improving the measurement performance. accuracy.

The pore diameter of the porous metal material is 0.05mm-0.2mm, the porosity of the porous metal material is 50%-96%, and the permeability of the porous metal material is 1×10 ^-9 m ² -1×10 ^-5 m ² .

The pitot tube device further comprises a connecting piece, the connecting piece is located in the hollow inner cavity of the main body, the sensor is located in the hollow inner cavity of the connecting piece, and the connecting piece is used for fixing the sensor. The hollow inner cavity of the connector includes a first section and a second section, the first section is used for fixing the sensor, and the second section is a hollow hole structure, which is used for fixing the tail cable of the sensor. The connector, the main body and the sensor are on the same central axis.

According to the requirements of the hypersonic wind tunnel flow field test, the present invention can be installed upright or horizontally at the designated position of the wind tunnel test section. modes, such as acoustic waves, vortex waves and entropy waves, but the effect is most pronounced for acoustic waves), the Pitot tube device can greatly improve the measurement accuracy of free-flow pressure pulsation in hypersonic wind tunnels.

Example 1

FIG. 1 shows a block diagram of Embodiment 1. FIG. The pitot tube device 8 includes a cylindrical body 1 and a sensor 2, and a connecting member 3 supported internally with the central axis 4 of the cylindrical body and the sensor as the center of rotation. In the embodiment 1 of Figure 1, the cylindrical body comprises a front flat 5 and a cylindrical shoulder 6 with a transition radius 7 therebetween. Therein, the transition radius 7 may be removed or replaced by other aerodynamically suitable contours. Considering the machining problem in Example 1, the main body of the cylindrical shape is divided into two sections at a distance from the front end plane L along the central axis. The length L is influenced by the axial length of the sensor and the design of the connections supported internally.

Figure 2 shows an exploded cross-sectional view of a pitot tube device, which can alleviate the disturbance reflection problem of pitot tube measurements in supersonic flow through the wave-transmitting properties of the porous metal material constituting the body. The main body includes a main body front section 11 and a main body rear section 12 .

Fig. 3 shows the assembled pipe, the main body 1 of the pitot tube device is formed of a porous metal material, and the porous metal material in Example 1 is a three-dimensional open-cell nickel alloy. The main body is divided into two stages of processing. The front section 11 of the main body includes a cavity for accommodating the sensor and an internal thread for mating with the connector, and the rear section 12 of the main body includes a cavity for accommodating the connector.

The supersonic flow forms a bow shock wave at the front end of the main part of the pitot tube, and the disturbance in the flow field is reflected back and forth between the front end surface of the pitot tube and the shock wave surface to form a disturbance oscillation, which affects the measurement of the pressure and the pulsation of the flow field by the pitot tube. And due to the focusing effect of the bow shock, the disturbance reflected by the shock surface will be collected in the pressure sensing area of the sensor, further increasing the uncertainty of the pitot measurement. Embodiment 1 The absorption of the disturbance of the flow field by the main body formed of the porous metal material can alleviate the reflection oscillation problem between the shock surface and the front end of the pitot tube. Thus, the accuracy of the pitot tube's measurement of the hypersonic flow field is improved.

The sensor included in the pitot tube device is a pressure sensor of the kulite XCQ-062 model in Example 1. Among them, the sensor can also be selected as other types of pressure sensors or other types of sensors, such as temperature sensors.

The connecting piece 3 inside the pitot tube device 8 is formed of ordinary metal 45 steel in the embodiment 1, and the connecting piece 3 has an external thread for connecting and mating with the main body 1 of the pitot tube device and a cylindrical hollow for accommodating the sensor 2 and its cable. cavity structure. In addition, the connector 3 also has an inner cylindrical step for accurately positioning the sensor 2 and an outer cylindrical step for accurately positioning the main body 1 of the pitot tube device. The main body rear section 12 of the main body 1 of the pitot tube device is directly sleeved on the periphery of the connector 3 and is in plane fit with the main body front section 11 of the main body 1 of the pitot tube device. The connector 3 can also be formed of other materials, and the connection and positioning form with the main body 1 and the sensor 2 can be changed. The connecting piece 3 plays the role of supporting the entire pitot tube device and positioning and connecting all the components of the pitot tube device into a whole.

Example 2

Figure 4 shows different ways of using pitot tubes for supersonic measurements to reduce perturbation reflections. In the second embodiment, the pitot tube device is directly composed of the main body 1 and the sensor 2 . The body 1 formed of the porous metal material can reduce the reflection of disturbances in the supersonic flow field. The positioning connection between the main body 1 and the sensor 2 is completed by the hollow inner cavity of the main body 1 . The outer contour of the body 1 can be modified to suit the aerodynamic shape. Sensor 2 can choose different models and types of sensors.

The use of porous metal materials in Pitot tubes to measure the pressure pulsation in hypersonic incoming flow can eliminate the influence of part of the incoming flow disturbance. The technical problem is that porous metal materials with different properties, such as permeability, porosity, etc., are not suitable for experimental measurement. The revised results of the results are different, but the overall trend is a good trend compared to conventional metal solid body pitot tubes. In order to overcome the above difficulties, the present invention conducts a series of parameter research through a hypersonic wind tunnel test to determine the parameter range of the porous metal material that can effectively improve the reliability of the experimental data. The pore size range of the porous metal material depends on the size of the pitot tube probe. For a pitot tube probe with a conventional size, the pore diameter of the porous metal material in Examples 1 and 2 is 0.05 mm to 0.2 mm, the porosity of the porous metal material is 50% to 96%, and the permeability of the porous metal material is 1× 10 ^-9 m ² to 1×10 ^-5 m ² . Appropriate parameter selection has a good effect on eliminating the sonic disturbance between the pitot tube probe and the out-of-body shock wave, and can improve the accuracy of the pitot tube's measurement results in hypersonic flow fields.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (4)

1. A pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel, characterized in that it comprises a main body and a sensor, the sensor is located in the hollow inner cavity of the main body, and the material of the main body is a porous metal material; When the pitot tube device is used for the measurement of pressure pulsation in a hypersonic wind tunnel, the main body composed of the porous metal material absorbs the flow field disturbance and weakens the reflection oscillation of the flow field disturbance between the shock surface and the front face of the pitot tube device, thereby improving the measurement performance. The accuracy of the flow field disturbance includes acoustic wave, vortex wave and entropy wave; The pore diameter of the porous metal material is 0.05mm to 0.2mm; the porosity of the porous metal material is 50% to 96%; the permeability of the porous metal material is 1×10 ⁻⁹ m ² to 1×10 ^{− 5} m ² . 2. The pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel according to claim 1, wherein the pitot tube device further comprises a connecting piece, and the connecting piece is located in the hollow inner cavity of the main body, The sensor is located in the hollow inner cavity of the connecting piece, and the connecting piece is used for fixing the sensor. 3. A pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel as claimed in claim 2, wherein the hollow inner cavity of the connecting piece comprises a first section and a second section, and the first section uses For fixing the sensor, the second section is a hollow hole structure, which is used to fix the tail cable of the sensor. 4. A pitot tube device for measuring pressure pulsation in a hypersonic wind tunnel according to claim 2, wherein the connecting member, the main body and the sensor are on the same central axis.

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