Omnidirectional four-hole water-cooling dynamic pressure probe for measuring backflow flow field of combustion chamber

Abstract

The utility model belongs to the technical field of high-temperature pressure testing, and discloses an omnidirectional four-hole water-cooling dynamic pressure probe for measuring a backflow flow field of a combustion chamber, which is characterized by comprising a probe head, a support rod and a cooling structure in the support rod. The probe head is provided with four pressure measuring holes, and the four pressure measuring holes are communicated with four dynamic pressure sensors packaged in the probe head. Four water inlet pipelines are arranged in the probe head and the supporting rod, and two grooves are formed in the section of a water outlet of each water inlet pipeline. The drainage ports are circumferentially and uniformly arranged at the tail of the probe, so that stress concentration at the tail of the probe support rod during drainage can be reduced. According to the invention, flow field parameters such as a deflection angle, total pressure, static pressure and Mach number in a flow field in a combustion chamber can be measured through calibration of a calibration wind tunnel, and a'backflow 'phenomenon in the flow field in the combustion chamber can also be measured. Compared with an existing probe, the probe can achieve flow field measurement in a high-temperature environment, temperature drift and even damage caused by heating of a probe head sensor are prevented, and then the accuracy of measured data is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature pressure testing, and relates to a dynamic pressure measurement device for a two-dimensional flow field. Specifically, it relates to an omnidirectional water-cooled dynamic pressure four-hole probe, which is applicable to measuring two-dimensional flow parameters such as deflection angle, total pressure, static pressure, and Mach number in a two-dimensional flow field in a combustion chamber, as well as the "recirculation" phenomenon of the airflow in the combustion chamber. Background Art

[0002] Combustion instability, also known as oscillatory combustion, is a phenomenon frequently encountered in various combustion devices such as gas turbine combustors, main combustors and afterburners of aeroengines, liquid and solid rocket engines, and industrial boilers. This phenomenon can cause the combustion device and even the entire system to vibrate violently, emit huge noises, increase the heat load, exacerbate the generation of pollutants, affect the normal operation of the combustion chamber and the system, and in severe cases, cause damage to system components.

[0003] Since the discovery of the oscillatory combustion phenomenon, people have attached great importance to it and carried out a large number of research works. However, due to the fact that the combustion instability phenomenon is a very complex problem, which itself involves multiple disciplines such as combustion, flow, heat transfer, and acoustics, the mechanism of oscillatory combustion is still unclear so far. Recent research believes that the combustion instability phenomenon is related to various processes in the combustion chamber, such as disturbances and vortex motions in the flow field, droplet injection, atomization, evaporation processes, turbulent combustion pulsations, and thermochemical kinetic pulsations.

[0004] Although the detailed mechanism of the response of various processes in the combustion chamber to combustion instability is still unclear so far, the most basic principle of generating combustion instability is very simple. If the combustion process occurs in a free and open space, the sound will simply dissipate. However, if the combustion process occurs in a closed space (such as a combustion chamber), the generated sound will be reflected by the boundary and then interact with the combustion process. The combustion process is very sensitive to changes in the flow field, and combustion instability may occur. The mechanism of generating combustion instability can be described in the following order:

[0005] 1) Perturbations to the flow or fluid thermodynamic parameters lead to fluctuations in the heat release rate;

[0006] 2) The fluctuations in the heat release rate generate vibrations of the sound pressure, and the sound waves are transmitted and reflected in the combustion chamber;

[0007] 3) The vibrations of the sound pressure cause changes in the flow or fluid thermodynamic parameters.

[0008] In summary, combustion instability is due to the complex feedback-type interaction between the periodic fluid and combustion processes (resulting in periodic heat release), which generates high-amplitude pressure vibrations in the combustion chamber and in turn leads to the recirculation phenomenon. Therefore, it is of great significance to conduct dynamic tests on the recirculation phenomenon in the combustion chamber flow field.

[0009] The temperature in the combustion chamber of an aeroengine can reach over 2500K, while the melting point of the main material, 304 stainless steel, used to manufacture the probe housing is approximately 800K - 1000K, which cannot withstand the high temperature in the aeroengine combustion chamber. This poses great difficulties in measuring parameters such as pressure and Mach number in the flow field of the aeroengine combustion chamber.

[0010] Existing probes (patent for invention: near-wall hot-wire probe capable of measuring recirculation, 2013200394540) use hot wires to measure the recirculation phenomenon in the flow field. However, the operating temperature of ordinary hot wires is below 400K. Since this probe does not have a cooling structure, the probe is extremely prone to damage during the measurement process. And the existing probes with water-cooling structures (patent for invention: a water-cooled probe, 2017207630951) cannot effectively measure the recirculation phenomenon in the flow field, and this probe has a large volume and is not convenient for application in measuring the flow field of an aeroengine combustion chamber.

[0011] The present invention, an omnidirectional four-hole water-cooled dynamic pressure probe for measuring the recirculation flow field in the combustion chamber, can effectively cool the probe head and the strut, and thus can perform dynamic pressure measurement of the flow field at high temperatures. At the same time, this probe can also measure the recirculation phenomenon in the flow field of the combustion chamber, and the interference of the probe head on the measurement of flow field parameters is also relatively small. When actually measuring the two-dimensional recirculation flow field of an aeroengine combustion chamber, the pressure sensing holes at the probe head of this water-cooled dynamic pressure four-hole probe are directly facing the oncoming flow direction, and a displacement mechanism is used to adjust the deflection angle of the probe comb. The flow field under different working conditions is measured at different deflection angles. By using the calibration wind tunnel calibration data obtained for data processing, two-dimensional flow parameters such as deflection angle, total pressure, static pressure, and Mach number in the two-dimensional recirculation flow field of the aeroengine combustion chamber can be obtained. After cooling water is introduced, it is possible to measure the flow field parameters in a high-temperature environment of 2500K, and the frequency response of this probe exceeds 25kHz. Summary of the Invention

[0012] The technical problem to be solved by the present invention is that when measuring the dynamic pressure of the two-dimensional flow field at the combustion chamber outlet, the surrounding environment temperature is too high, and the excessive temperature will damage the probe. Therefore, a cooling measure needs to be taken to reduce the temperature around the probe strut; at the same time, since there is a recirculation phenomenon in the flow field of the aeroengine combustion chamber, a structure needs to be designed to measure the recirculation phenomenon in the aeroengine combustion chamber.

[0013] To this end, the present invention provides an omnidirectional four-hole water-cooled dynamic pressure probe for measuring the recirculation flow field in a combustion chamber. During measurement, coolant is introduced into the probe's water inlet, flows through the interior of the probe, and then is discharged through the drain pipe. Compared with existing probes, by evenly arranging four pressure measurement holes circumferentially at the probe head, omnidirectional measurement of flow field parameters can be achieved, and thus the recirculation phenomenon in the flow field can be detected. At the same time, a special cooling structure is added inside the probe, enabling the probe to have stronger high-temperature resistance and making it more suitable for measuring the flow field in an aero-engine combustion chamber. When actually measuring the two-dimensional recirculation flow field in the combustion chamber, the pressure sensing holes at the head of this water-cooled dynamic pressure four-hole probe are aligned with the oncoming flow direction, and a displacement mechanism is used to adjust the deflection angle of the probe comb. The flow field under different working conditions is measured at different deflection angles. By using the calibration wind tunnel calibration data obtained for data processing, two-dimensional flow parameters such as the deflection angle, total pressure, static pressure, and Mach number in the two-dimensional recirculation flow field of the aero-engine combustion chamber can be obtained. After introducing cooling water, it is possible to measure the flow field parameters in a high-temperature environment of 2500K, and the probe's frequency response exceeds 25kHz.

[0014] The solution of the present invention is as follows:

[0015] 1. An omnidirectional four-hole water-cooled dynamic pressure probe for measuring the recirculation flow field in a combustion chamber, mainly composed of a probe head (1), a probe strut (2), a No. 1 pressure measurement channel (3), a No. 2 pressure measurement channel (4), a No. 3 pressure measurement channel (5), a No. 4 pressure measurement channel (6), a No. 1 water inlet pipe (7), a No. 2 water inlet pipe (8), a No. 3 water inlet pipe (9), a No. 4 water inlet pipe (10), a No. 1 drain port (11), a No. 2 drain port (12), a No. 3 drain port (13), and a No. 4 drain port (14). It is characterized in that: the probe head (1) has a cylindrical shape, with a diameter of 8 mm to 16 mm and a length of 20 mm to 40 mm. The probe head (1) and the probe strut (2) housing are both made of stainless steel material, and their surfaces are both coated with high-temperature resistant and heat-insulating coatings.

[0016] 2. Further, the pressure measurement holes are evenly distributed circumferentially on the side of the probe head (1), with a hole diameter of 0.8 mm to 1.6 mm, and the distance from the center line of the pressure measurement hole to the upper bottom surface of the probe head (1) is 3 mm to 8 mm.

[0017] 3. Further, the No. 1 pressure measurement channel (3), the No. 2 pressure measurement channel (4), the No. 3 pressure measurement channel (5), and the No. 4 pressure measurement channel (6) are each composed of two parts. The first part is a quarter-elliptical pipe with a major axis of 6 mm to 12 mm and a minor axis of 3 mm to 8 mm, and the second part is a straight pipe. The two parts of the pressure measurement channel are smoothly connected.

[0018] 4. Further, the four pressure sensors are respectively installed in the No. 1 pressure measurement channel (3), No. 2 pressure measurement channel (4), No. 3 pressure measurement channel (5), and No. 4 pressure measurement channel (6) of the probe head (1). The number of sensors is the same as the number of pressure measurement holes. The cables of the sensors are sleeved inside the probe and led out from the tail of the probe. The measurement accuracy of the sensors is 0.1% - 0.5%, and the natural frequency is 300 Hz - 500 kHz.

[0019] 5. Further, the water inlet system inside the probe consists of the No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10). The No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10) are circumferentially and evenly distributed inside the probe. The diameter of the water inlet pipes is 2 mm - 4 mm. The distance from the center line of each water inlet pipe to the center line of the probe head is 3 mm - 8 mm. Moreover, the shell walls of the No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10) all overlap with the shell wall of the probe head (1). The No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10) and the probe head (1) are of an integral structure.

[0020] 6. Further, the water inlets of the No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10) are located at the tail of the probe, and the water outlets are respectively near the four pressure measurement holes of the probe head (1). Two grooves are opened at the water outlets of each water inlet pipe, and the grooves opened at the cross-section of the water outlet of each water inlet pipe are symmetrically distributed.

[0021] 7. Further, the opening of each groove faces downward at the connection of the pressure measurement channel adjacent to it and the probe head (1). The groove is composed of three surfaces. The front and rear two surfaces are toroidal surfaces, with diameters of 8 mm - 16 mm and 4 mm - 12 mm respectively. The depth of the groove is 1 mm - 5 mm.

[0022] 8. The No. 1 drain port (11), No. 2 drain port (12), No. 3 drain port (13), and No. 4 drain port (14) are circumferentially and evenly arranged at the bottom of the probe. The diameter of each drain port is 2 mm - 5 mm. The distance from the center of each drain port to the central axis of the probe support rod (2) is 3 mm - 8 mm.

[0023] The present invention relates to an omnidirectional four-hole water-cooled dynamic pressure probe for measuring the recirculation flow field in a combustion chamber. After calibration in a calibration wind tunnel, calibration data can be obtained. When actually measuring the two-dimensional recirculation flow field in an aero-engine combustion chamber, the pressure sensing holes at the head of the water-cooled dynamic pressure four-hole probe are aligned with the oncoming flow direction, and a displacement mechanism is used to adjust the deflection angle of the probe comb. The flow field under different working conditions is measured at different deflection angles. By using the calibration data obtained from the calibration wind tunnel for data processing, two-dimensional flow parameters such as the deflection angle, total pressure, static pressure, and Mach number in the two-dimensional recirculation flow field of the aero-engine combustion chamber can be obtained. After cooling water is introduced, it is possible to measure the flow field parameters in a high-temperature environment of 2500K, and the frequency response of the probe exceeds 25kHz.

[0024] The present invention, an omnidirectional four-hole water-cooled dynamic pressure probe for measuring the recirculation flow field in a combustion chamber, has the following beneficial effects:

[0025] Beneficial effect one: It can measure the flow field with recirculation in a high-temperature environment. Due to the water-cooled structure, after injecting cooling water, the overall cooling effect of the probe is improved, so that when the probe is in a high-temperature environment of 2500K, the temperature near the pressure sensor can be reduced to below 500K. After being calibrated in a calibration wind tunnel, the invention can be used to measure parameters such as the total pressure, static pressure, deflection angle, and Mach number of the two-dimensional flow field in an aero-engine combustion chamber. At the same time, it can measure the recirculation phenomenon in the aero-engine combustion chamber, providing measured data for improving the performance of the aero-engine combustion chamber.

[0026] Beneficial effect two: The probe can reduce the interference caused by the reflection of pressure waves to the upstream of the flow field and prevent the direct erosion of the high-temperature gas flow on the pressure measurement channel. The pressure measurement channels at the head of the probe all have a certain angle of bend, which can avoid pressure pulsation and prevent the direct erosion of the high-temperature gas flow on the sensing part of the pressure sensor, thereby extending the service life of the pressure sensor. In addition, when pressure waves propagate, they will reflect. When the pressure wave propagates to one end of the pipeline, the wave will reflect back from the end of the pipeline. The pressure sensing holes at the head of the probe have a certain angle of bend, which can reduce the interference caused by the reflection of pressure waves to the upstream of the flow field and make the measurement more accurate.

[0027] Beneficial effect three: The grooves opened at the water outlets of each water inlet pipe can enhance the impact cooling effect near the pressure measurement holes. Two grooves are opened on the cross-section of the water outlet of each water inlet pipe, and each groove is respectively aligned with the connection between the pressure measurement pipeline close to it and the probe head, enhancing the impact cooling effect at this position.

[0028] Beneficial effect four: Avoid the occurrence of local ablation. When the cooling liquid enters through the four water inlets, it can ensure uniform water inlet, avoid the appearance of cavities inside the probe and insufficient heat transfer, and thus avoid the occurrence of local ablation.

[0029] Beneficial effect five: While strengthening the water inlet pipe inside the probe, the heat is quickly transferred from the probe head housing to the cooling water. An integrated reinforcement is designed at a certain position from the water outlet of the water inlet pipe, so that the probe head housing and the water inlet pipe share part of the wall surface, which can enhance the heat conduction effect between the wall surface of the probe head housing and the wall surface of the water inlet pipe. The water inlet pipe has a large contact area with the cooling water, and the heat can be quickly transferred to the cooling water through convective heat transfer. Therefore, this reinforcement method can quickly transfer the heat to the wall surface of the probe head housing while strengthening the water inlet pipe.

[0030] Beneficial effect six: It can prevent stress concentration in the probe housing. Four drain ports are evenly arranged circumferentially at the bottom of the probe, which can prevent stress concentration in the probe housing caused by excessive local water pressure. Description of the Drawings

[0031] Figure 1 It is a schematic diagram of the overall structure of an omnidirectional water-cooled dynamic pressure four-hole probe in an embodiment of the present invention.

[0032] Figure 2 It is a cross-sectional view taken along the A-A section.

[0033] Figure 3 It is a cross-sectional view taken along the B-B section.

[0034] Figure 4 It is a cross-sectional view taken along the C-C section.

[0035] Figure 5 It is a cross-sectional view taken along the D-D section.

[0036] Wherein: 1-probe head, 2-probe rod, 3-pressure measurement channel 1, 4-pressure measurement channel 2, 5-pressure measurement channel 3, 6-pressure measurement channel 4, 7-water inlet pipe 1, 8-water inlet pipe 2, 9-water inlet pipe 3, 10-water inlet pipe 4, 11-drain port 1, 12-drain port 2, 13-drain port 3, 14-drain port 4. Detailed Embodiment

[0037] The present invention will be described in detail below in conjunction with the drawings and a specific embodiment, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0038] The present invention will be described in detail below in conjunction with the drawings and specific examples.

[0039] Such as Figure 1As shown in the figure, this embodiment introduces an omnidirectional water-cooled dynamic pressure four-hole probe, which mainly consists of a probe head (1), a probe rod (2), a No. 1 pressure measurement channel (3), a No. 2 pressure measurement channel (4), a No. 3 pressure measurement channel (5), a No. 4 pressure measurement channel (6), a No. 1 water inlet pipe (7), a No. 2 water inlet pipe (8), a No. 3 water inlet pipe (9), a No. 4 water inlet pipe (10), a No. 1 drain port (11), a No. 2 drain port (12), a No. 3 drain port (13), and a No. 4 drain port (14). It is characterized in that: the probe head (1) has a cylindrical shape, with a diameter of 16 mm and a length of 30 mm. The probe housing is made of stainless steel and is coated with high-temperature heat-insulating paint; the pressure measurement holes are evenly distributed circumferentially on the side of the probe head (1), with a hole diameter of 1 mm, and the center line of the pressure measurement hole is 6 mm away from the upper bottom surface of the probe head (1).

[0040] The relative positions of the water inlet pipes of this probe are as Figure 2 shown. The water inlet system inside the probe consists of a No. 1 water inlet pipe (7), a No. 2 water inlet pipe (8), a No. 3 water inlet pipe (9), and a No. 4 water inlet pipe (10). The No. 1 water inlet pipe (7), the No. 2 water inlet pipe (8), the No. 3 water inlet pipe (9), and the No. 4 water inlet pipe (10) are evenly distributed circumferentially inside the probe. The diameter of the water inlet pipes is 3 mm, and the distance between the center line of each water inlet pipe and the center line of the probe head (1) is 5 mm.

[0041] The cooling system of this probe is as Figure 3As shown in the figure. The shell walls of the No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10) all overlap with the shell wall of the probe head (1). The No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10) and the probe head (1) are of an integral structure. An integral reinforcement is designed at a certain place near the water outlet of the small water inlet pipe, so that the shell of the probe head (1) shares part of the wall with the No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10). Furthermore, the heat conduction effect between the shell wall of the probe head (1) and the wall of the No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10) can be enhanced. And since the contact area with the cooling water is relatively large, the heat can be quickly transferred to the cooling water through convective heat transfer. Therefore, this reinforcement method can quickly transfer the heat to the shell wall of the probe head (1) while strengthening the No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10). The water inlets of the No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10) are located at the probe tail, and the water outlets are respectively near the four pressure measurement holes of the probe head (1). Two grooves are opened at the water outlets of each water inlet pipe. The grooves are symmetrically distributed, and the groove openings are respectively facing the lower part of the connection between each pressure measurement channel adjacent to the groove and the probe head (1).

[0042] The cross-section of the water outlet of the probe water inlet pipe is as Figure 4 shown. The water outlet grooves of the No. 1 water inlet pipe (7), No. 2 water inlet pipe (8), No. 3 water inlet pipe (9), and No. 4 water inlet pipe (10) of the probe are composed of three surfaces. The front and back two surfaces are toroidal surfaces with diameters of 16 mm and 5 mm respectively, and the groove depth is 2 mm.

[0043] The distribution of the drain ports at the bottom of the probe is as Figure 5 shown. The No. 1 drain port (11), No. 2 drain port (12), No. 3 drain port (13), and No. 4 drain port (14) are evenly arranged circumferentially at the bottom of the probe. The diameter of each drain port is 3 mm, and the center of each drain port is 6 mm away from the central axis of the probe support rod (2).

[0044] The present invention relates to an omnidirectional four-hole water-cooled dynamic pressure probe for measuring the recirculation flow field of a combustion chamber. After calibration in a calibration wind tunnel, calibration data can be obtained. When actually measuring the two-dimensional recirculation flow field of an aeroengine combustion chamber, the pressure sensing holes at the head of the water-cooled dynamic pressure four-hole probe are aligned with the oncoming flow direction, and a displacement mechanism is used to adjust the deflection angle of the probe comb. The flow fields under different working conditions are measured at different deflection angles. By using the calibration data obtained from the calibration wind tunnel for data processing, two-dimensional flow parameters such as the deflection angle, total pressure, static pressure, and Mach number in the two-dimensional recirculation flow field of the aeroengine combustion chamber can be obtained. After cooling water is introduced, dynamic measurement of the flow field parameters can be realized in a high-temperature environment of 2500K, and the frequency response of the probe exceeds 25kHz.

Claims

1. An omnidirectional four-hole water-cooled dynamic pressure probe for measuring the reflow flow field of a combustion chamber, mainly comprising a probe head (1), a probe support rod (2), a No. 1 pressure measuring channel (3), a No. 2 pressure measuring channel (4), a No. 3 pressure measuring channel (5), a No. 4 pressure measuring channel (6), a No. 1 water inlet pipe (7), a No. 2 water inlet pipe (8), a No. 3 water inlet pipe (9), a No. 4 water inlet pipe (10), a No. 1 drain port (11), a No. 2 drain port (12), a No. 3 drain port (13), and a No. 4 drain port (14), characterized in that: The probe head (1) is cylindrical in shape, with a diameter of 8 mm to 16 mm and a length of 20 mm to 40 mm. The probe support rod (2) is cylindrical in shape, with a diameter of 12 mm to 20 mm and a length of 30 mm to 200 mm. The shells of the probe head (1) and the probe support rod (2) are both made of stainless steel, and the surface is coated with a high temperature resistant heat insulating coating. The pressure measuring holes are evenly distributed on the side of the probe head (1) in the circumferential direction, and the hole diameter thereof is 0.8 mm to 1.6 mm. The distance from the center line of the pressure measuring hole to the upper bottom surface of the probe head (1) is 3 mm to 8 mm. The No. 1 pressure measuring channel (3), the No. 2 pressure measuring channel (4), the No. 3 pressure measuring channel (5), and the No. 4 pressure measuring channel (6) are all composed of two parts, the first part is a quarter-elliptical pipe with a long axis of 6 mm to 12 mm and a short axis of 3 mm to 8 mm, and the second part is a straight pipe, and the two parts of the pressure measuring channel are smoothly connected; The sensor is installed on the probe head, and the number of sensors is consistent with the number of pressure measuring holes. The sensor cable is set inside the probe and led out from the tail of the probe. The sensor measurement accuracy is 0.1% to 0.3%, and the natural frequency is 300Hz to 500Hz. The water inlet system inside the probe is composed of a No. 1 water inlet pipe (7), a No. 2 water inlet pipe (8), a No. 3 water inlet pipe (9), and a No. 4 water inlet pipe (10). The No. 1 water inlet pipe (7), the No. 2 water inlet pipe (8), the No. 3 water inlet pipe (9), and the No. 4 water inlet pipe (10) are uniformly distributed in the circumferential direction inside the probe. The diameters of the No. 1 water inlet pipe (7), the No. 2 water inlet pipe (8), the No. 3 water inlet pipe (9), and the No. 4 water inlet pipe (10) are all 2 mm to 4 mm. The distance between the center line of each water inlet pipe and the center line of the probe head (1) is 3 mm to 8 mm. The shell walls of the No. 1 water inlet pipe (7), the No. 2 water inlet pipe (8), the No. 3 water inlet pipe (9), and the No. 4 water inlet pipe (10) all overlap with the shell wall of the probe head (1). The No. 1 water inlet pipe (7), the No. 2 water inlet pipe (8), the No. 3 water inlet pipe (9), and the No. 4 water inlet pipe (10) are an integrated structure with the probe head (1). The water inlets of the No. 1 water inlet pipe (7), the No. 2 water inlet pipe (8), the No. 3 water inlet pipe (9), and the No. 4 water inlet pipe (10) are located at the tail of the probe, and the water outlets are respectively located near the four pressure measuring holes of the probe head (1). The water outlet of each water inlet pipe is provided with two grooves, and the grooves provided on the cross-sections of the water inlet pipe outlets are symmetrically distributed. Each groove opening is directly opposite to the lower part of the connection between the adjacent pressure measuring channel and the probe head. The groove is composed of three surfaces. The front and rear surfaces are annular surfaces with diameters of 8 mm to 16 mm and 4 mm to 12 mm respectively. The groove depth is 1 mm to 5 mm. A No. 1 drainage port (11), a No. 2 drainage port (12), a No. 3 drainage port (13), and a No. 4 drainage port (14) are evenly arranged around the bottom of the probe. The diameter of each drainage port is 2 mm to 5 mm, and the center of each drainage port is 3 mm to 8 mm away from the central axis of the probe support rod (2).

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