A supersonic probe and calibration method thereof

Abstract

A supersonic probe and a calibration method thereof, relating to a probe and a calibration method. The probe body adopts a seamless steel pipe with a bend near the bottom end, and four channels extending with the probe body are arranged in the middle position inside the probe body. The four channels are arranged at equal angles along the axis of the probe body and are solidly welded to the intervals between the probe body. The front edge of the probe body is polished to form a conical probe for the measuring end. The four channels are connected with the conical probe to form four measuring holes, and the measuring holes are located at the 50% generatrix of the conical probe. One of the channels is connected with the conical probe along the axial direction of the probe body to form a total pressure hole, and the other three channels are connected along the vertical direction of the generatrix of the conical probe to form static pressure holes. During the measurement process, a small shock wave angle can be maintained, and the shock wave loss is small, which helps to improve the measurement accuracy.

Description

Technical Field

[0001] The invention relates to a probe and a calibration method thereof, in particular to a supersonic probe and a calibration method thereof, belonging to the technical field of contact flow field measurement. Background Art

[0002] The use of multi-hole pressure probes is extremely common in aerodynamic measurements. Directional probes can be used to determine the total and static pressures, flow velocity and flow direction in a three-dimensional flow field through proper calibration. When the pressure and velocity gradients are very small, multi-hole pressure probes can accurately measure the incoming flow direction, total pressure and static pressure. Compared with non-contact measurement methods, multi-hole pressure probes have the advantages of relatively low maintenance, cost and simple operation, so they are often used in research projects. In principle, any aerodynamic body with multiple holes, such as a semicircular head, a spherical head, a wedge head or a conical head, can be used to measure three-dimensional flows. Measuring the total pressure and static pressure and two angles in mutually perpendicular planes in three-dimensional flows requires at least four holes on the aerodynamic body. However, in order to improve symmetry and measurement angle range, five-hole and seven-hole probes are often selected. However, when measuring in supersonic conditions, the presence of the total pressure hole at the front end of the conventional five-hole or seven-hole probe often leads to blunt body shock waves at the leading edge of the probe, increasing flow field losses and reducing measurement accuracy.

[0003] Therefore, in order to reduce the shock wave loss generated by the probe under supersonic conditions, it is extremely important to develop a supersonic probe and its calibration method. Summary of the invention

[0004] In order to solve the shortcomings of the background technology, the present invention provides a supersonic probe and a calibration method thereof, which can maintain a small shock wave angle during the measurement process, with small shock wave loss, and help to improve the measurement accuracy.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A supersonic probe and a calibration method thereof, comprising a probe body and a conical probe, wherein the probe body adopts a seamless steel pipe with a bend angle provided near the bottom end, and four channels extending with the probe body are provided at the middle position inside the probe body, and the four channels are divided into an inlet section and a collection section, wherein the inlet section corresponds to the probe body at the bottom area of ​​the bend, and the collection section corresponds to the probe body at the top area of ​​the bend, the four channels are arranged at equal angles along the axis of the probe body and are solidly welded to the probe body as a whole, the front edge of the probe body is polished as a measuring end to form a conical probe, the four channels are all connected with the conical probe to form four measuring holes, and the four measuring holes are all located at the 50% generatrix of the conical probe, one of the channels is connected with the conical probe along the axial direction of the probe body to form a No. 1 measuring hole as a total pressure hole, and the other three channels are connected along the vertical direction of the generatrix of the conical probe to form No. 2 measuring holes, No. 3 measuring holes and No. 4 measuring holes as static pressure holes.

[0007] A method for calibrating an ultrasonic probe, the calibration method comprising:

[0008] The average pressure value of the three static pressure holes:

[0009]

[0010] Airflow yaw angle α calibration coefficient:

[0011]

[0012] Airflow pitch angle β calibration coefficient:

[0013]

[0014] Total pressure calibration factor:

[0015]

[0016] Static pressure calibration factor:

[0017]

[0018] Where P 1 , P 2 , P 3 and P 4 Respectively represent the pressures measured at No. 1, No. 2, No. 3 and No. 4 measuring holes, P t and P s Represent the total pressure and static pressure of the incoming flow respectively.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The probe of the present invention can maintain a small shock wave angle during the measurement process. The semi-cone angle of the conical probe is 15°, and the radius is 2mm. The probe has only four measuring holes, and the radius of the measuring hole is 0.1mm. Compared with the blunt body shock wave generated by the multi-hole probe with a total pressure hole at the leading edge, it has a smaller shock wave loss, which helps to improve the measurement accuracy.

[0021] 2. Measuring hole No. 1 penetrates the surface of the conical probe along the axial direction of the probe body, and measures the total pressure with velocity components as much as possible to ensure the orthogonality of the calibration curve grid composed of coefficients in various directions. Measuring holes No. 2-4 penetrate the surface of the conical probe along the direction perpendicular to the generatrix, and measure the static pressure of the conical surface as much as possible, and a new calibration coefficient formula is defined for the probe. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the probe of the present invention;

[0023] Figure 2 It is a schematic structural diagram of a conical probe of the probe of the present invention;

[0024] Figure 3 It is a left side view of the conical probe of the probe of the present invention;

[0025] Figure 4 It is a right side view of the conical probe of the probe of the present invention;

[0026] Figure 5 It is a schematic diagram of the structure of four channels of the present invention;

[0027] Figure 6 It is a schematic diagram of the pitch angle and yaw angle of the probe of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] like Figure 1 to Figure 6As shown, a supersonic probe includes a probe body 5 and a conical probe 6. The probe body 5 is a seamless steel pipe with a bend near the bottom end. Four channels extending from the probe body 5 are arranged in the middle of the probe body 5. The four channels are divided into an inlet section 7 and a collection section 8. The inlet section 7 is arranged corresponding to the probe body 5 at the bottom area of ​​the bend, and the collection section 8 is arranged corresponding to the probe body 5 at the top area of ​​the bend. The four channels are arranged at equal angles along the axis of the probe body 5 and are solidly welded to the probe body 5. The probe The front edge of the body 5 is polished as the measuring end to form a conical probe 6. The semi-cone angle of the conical probe 6 is preferably set to 15°, and the radius is preferably set to 2mm. Four channels are all connected with the conical probe 6 to form 4 measuring holes, and the 4 measuring holes are all located at the 50% generatrix of the conical probe 6. The radius of the 4 measuring holes is preferably set to 0.1mm, and one of the channels is connected with the conical probe 6 along the axial direction of the probe body 5 to form measuring hole No. 1 as a total pressure hole, and the remaining three channels are connected along the vertical direction of the generatrix of the conical probe 6 to form measuring hole No. 2, measuring hole No. 3 and measuring hole No. 4 as static pressure holes.

[0030] like Figure 1 to Figure 6 As shown, a calibration method of an ultrasonic probe comprises:

[0031] The average pressure value of the three static pressure holes:

[0032]

[0033] Airflow yaw angle α calibration coefficient:

[0034]

[0035] Airflow pitch angle β calibration coefficient:

[0036]

[0037] Total pressure calibration factor:

[0038]

[0039] Static pressure calibration factor:

[0040]

[0041] Where P 1 , P 2 , P 3 and P 4 Respectively represent the pressures measured at No. 1, No. 2, No. 3 and No. 4 measuring holes, P t and P s They represent the total incoming pressure and static pressure respectively (measured by the Pitot tube at the wind tunnel inlet).

[0042] The semi-cone angle of the conical probe of the present invention is preferably set to 15°, the radius is preferably set to 2 mm, and the measuring hole radius is preferably set to 0.1 mm. While reducing the volume of the conical probe 6 as much as possible, the necessary installation volume of each measuring hole is guaranteed. The probe has only 4 measuring holes, and the total pressure hole at the leading edge of the conventional probe is eliminated to prevent the generation of blunt body shock waves at the leading edge of the probe in the super-transonic flow field. Measuring hole No. 1 is used to penetrate the surface of the conical probe along the axial direction of the probe body to replace the total pressure hole to collect the total pressure. Measuring holes No. 2-4 penetrate the surface of the conical probe along the direction perpendicular to the busbar to collect static pressure, and a new calibration coefficient formula is defined for the probe.

[0043] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0044] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An ultrasonic probe, characterized in that: The invention comprises a probe body (5) and a conical probe (6), wherein the probe body (5) is a seamless steel pipe having a bend at a position near the bottom end, and four channels extending along with the probe body (5) are arranged at the middle position inside the probe body (5), and the four channels are divided into an inlet section (7) and a collection section (8), wherein the inlet section (7) and the probe body (5) are arranged correspondingly at the bottom area of ​​the bend, and the collection section (8) and the probe body (5) are arranged correspondingly at the top area of ​​the bend, and the four channels are arranged at equal angles along the axis of the probe body (5) and are connected to the probe body (6) at the same angle. 5) are solidly welded together, the front edge of the probe body (5) is ground as a measuring end to form a conical probe (6), four channels are connected with the conical probe (6) to form four measuring holes, and the four measuring holes are all located at the 50% generatrix of the conical probe (6), one of the channels is connected with the conical probe (6) along the axial direction of the probe body (5) to form a No. 1 measuring hole (1) as a total pressure hole, and the other three channels are connected along the vertical direction of the generatrix of the conical probe (6) to form a No. 2 measuring hole (2), a No. 3 measuring hole (3) and a No. 4 measuring hole (4) as static pressure holes.

2. An ultrasonic probe according to claim 1, characterized in that: The semi-cone angle of the conical probe (6) is set to 15°, and the radius is 2 mm.

3. The ultrasonic probe according to claim 1, characterized in that: The radius of the four measuring holes is 0.1 mm.

4. A method for calibrating an ultrasonic probe, characterized in that: The probe according to claim 1, wherein the calibration method comprises: The average pressure value of the three static pressure holes: Airflow yaw angle α calibration coefficient: Airflow pitch angle β calibration coefficient: Total pressure calibration factor: Static pressure calibration factor: Where P1, P2, P3 and P4 represent the pressures measured at No. 1, No. 2, No. 3 and No. 4 measuring holes respectively. t and P s Represent the total pressure and static pressure of the incoming flow respectively.

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