CN111238575A

CN111238575A - Composite three-hole pressure-temperature probe

Info

Publication number: CN111238575A
Application number: CN202010235407.8A
Authority: CN
Inventors: 钟兢军; 阚晓旭; 吴宛洋; 杨凌
Original assignee: Shanghai Maritime University
Current assignee: Shanghai Maritime University
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2020-06-05

Abstract

The utility model provides a three hole pressure-temperature probe of compound, contain three pressure-measuring pipes that set up inside the probe body of rod, two total temperature thermocouples, two static pressure-measuring pipes and two quiet temperature thermocouples, the front end of the probe body of rod is quiet parameter section, the section of drawing forth is connected in the middle section of the probe body of rod, probe head and quiet parameter section are connected to the changeover portion, three pressure-measuring pipes and two total temperature thermocouples's detection end sets up at the probe head, the detection end setting of two static pressure-measuring pipes and two quiet temperature thermocouples is at the lateral wall of quiet parameter section, all pressure-measuring pipes and thermocouple stretch out from the section of drawing forth. The invention realizes the simultaneous and simultaneous measurement of the pneumatic parameters of total temperature, static temperature, total pressure, static pressure, Mach number, two-dimensional flow velocity, deflection angle of air flow and the like of the flow field under the conditions of transonic velocity and supersonic velocity incoming flow, and can effectively control the geometric dimension of the probe so as to avoid larger interference of the flow field caused by overlarge dimension.

Description

Composite three-hole pressure-temperature probe

Technical Field

The invention relates to the field of pressure, temperature and speed testing, in particular to a composite three-hole pressure-temperature probe.

Background

The pneumatic probe is the most main and convenient measuring tool in the wind tunnel experiment of the impeller machinery. At present, three-hole pressure probes commonly adopted in a plane cascade wind tunnel experiment can only measure the total pressure, the static pressure, the Mach number and the deflection angle of airflow at a measuring point. If a two-dimensional velocity value of the gas flow is desired, a temperature sensor is also required to measure the static temperature of the local gas flow, which undoubtedly affects the use of current three-hole pressure probes.

For low-speed and high-subsonic-speed cascade wind tunnel experiments, most of the wind tunnel is provided with a temperature probe at a stable section to measure the temperature of airflow, and meanwhile, the small temperature difference drop of the airflow between the stable section of the wind tunnel and a measuring point is received. However, under the condition of cross-over and supersonic incoming flow, the local entropy increase is caused by the shock wave structure appearing at the head part of the pneumatic probe, so that the temperature of the airflow is suddenly increased, and the pressure and the temperature at the same measuring point must be measured. To achieve this, two methods are currently widely used: one is that a pneumatic pressure probe and a temperature probe are respectively used for measuring pneumatic parameters at the same measuring point, but the pneumatic parameters at the same time cannot be measured; the other method is to combine two independent pressure probes and temperature probes by means of binding, welding and the like, so that the pneumatic parameters can be measured simultaneously. However, the two probes are not completely located at the same spatial position, and the combined probe has a larger geometric size than a common pneumatic probe, which causes a large interference to the flow field. In addition, some total pressure-total temperature probes embed a total temperature thermocouple near a total pressure piezometer tube, and although the mode realizes simultaneous and same-ground measurement, the arrangement of the total temperature thermocouple can influence the symmetry of deflection angle characteristics of the probes, thereby reducing the measurement range of the whole pneumatic probe.

Therefore, most of the existing pneumatic probes cannot obtain pneumatic parameters such as total temperature, static temperature, total pressure, static pressure, mach number, two-dimensional flow velocity, deflection angle of air flow and the like at the same time at the same space point.

Disclosure of Invention

The invention provides a composite three-hole pressure-temperature probe.A total temperature thermocouple and a static temperature thermocouple are embedded in the traditional three-hole pressure probe, so that the total temperature, the static temperature, the total pressure, the static pressure, the Mach number, the two-dimensional flow velocity, the deflection angle of airflow and other pneumatic parameters of a convection field are simultaneously and simultaneously measured under the conditions of transonic speed and supersonic incoming flow, the geometric dimension of the probe can be effectively controlled, and the phenomenon that the probe is overlarge in dimension to cause larger interference to the convection field is avoided.

In order to achieve the above object, the present invention provides a composite three-hole pressure-temperature probe, comprising: the probe comprises three pressure-measuring tubes, two total-temperature thermocouples, two static pressure-measuring tubes and two static-temperature thermocouples, wherein the three pressure-measuring tubes, the two total-temperature thermocouples, the two static pressure-measuring tubes and the two static-temperature thermocouples are arranged in a probe rod body;

the detection ends of the three pressure-measuring tubes and the two total temperature thermocouples are arranged at the head of the probe, the detection ends of the two static pressure-measuring tubes and the two static temperature thermocouples are arranged on the side wall of the static parameter section, and all the pressure-measuring tubes and the thermocouples extend out of the leading-out section.

The end part of the pressure measuring head is wedge-shaped, and the wedge angle of the wedge is 10-30 degrees.

The pressure piezometer tube and the two total temperature thermocouples are arranged at the top end wedge of the pressure measuring head part, the pressure piezometer tube is positioned in the middle, the two total temperature thermocouples are symmetrically positioned at two sides of the pressure piezometer tube, and the other two pressure piezometer tubes are respectively positioned on two side walls of the top end wedge of the probe head part.

And a stagnation cover is arranged at the detection end of the total temperature thermocouple.

The transition section is a duckbill regular body, the cross section of the front end of the transition section, which is connected with the probe head, is rectangular, and the cross section of the tail end of the transition section, which is connected with the static parameter section, is circular.

The two static pressure measuring pipes are arranged on the side wall of the static parameter section in a centrosymmetric manner around the central axis of the static parameter section, and the two static temperature thermocouples are arranged on the side wall of the static parameter section in a centrosymmetric manner around the central axis of the static parameter section.

The diameter of the static parameter section is less than or equal to 10 mm.

The probe rod body contain front end, middle section and rear end, front end, middle section and rear end formation "pi" style of calligraphy structure, the geometric structure that is located the quiet parameter section and draws the middle section body of rod between the section is cylindrical, the geometric structure that is located the rear end body of rod between section and the mount pad locating piece of drawing is the cuboid.

The probe comprises a reinforcing rib, the reinforcing rib is respectively arranged at a turning position between the front end and the middle section of the probe rod body and a turning position between the middle section and the rear end of the probe rod body, the section of the reinforcing rib is a triangle with curved edges, two straight edges of the triangle are respectively contacted with the probe rod body, the curved edges of the triangle are not contacted with the probe rod body, and the curved edges face to the direction of air flow.

The leading-out section is of a hollow semicircular structure, the bottom of the leading-out section is a rectangular plane, the vertical section of the leading-out section is semicircular, the two total temperature thermocouples and the two static temperature thermocouples are linearly arranged on the leading-out section, the two total temperature thermocouples are arranged in the middle of the leading-out section, the three pressure piezometers and the two static pressure piezometers are linearly arranged on the leading-out section, and the three pressure piezometers are arranged in the middle of the leading-out section.

Compared with the prior art, the invention has the following beneficial effects:

1. the total temperature thermocouple is embedded in the probe head instead of being bound outside the probe rod body, so that the size of the probe head is greatly reduced, the structural size same as that of a traditional pressure probe is reserved, and the interference of the composite probe on a flow field is effectively reduced.

2. The probe head and the static parameter section are connected by adopting the transition section of the duckbill-shaped regular body with a special variable diameter profile structure, so that the supersonic air flow generates a series of weak oblique shock waves on the profile of the transition section, and the supersonic air flow is in an isentropic compression flowing state, thereby providing guarantee for accurately measuring the static pressure and static temperature of the air flow which are not influenced by the shock wave structure.

3. By adopting the transition section reducing structure form, on one hand, the geometric dimension of the probe head is effectively reduced, the interference degree of the probe head on the flow field can be weakened, on the other hand, the geometric dimension of the probe rod body is ensured, and the rigidity of the probe rod body can be enhanced to bear the impact force of the supersonic incoming flow.

4. The adoption stiffening rib, mount pad adopt can dismantle, adjustable position's locating piece, processing, installation and operation convenient to use guarantee that the probe has lower manufacturing and maintenance cost simultaneously with higher intensity.

Drawings

Fig. 1 is a main structure view of a composite three-hole pressure-temperature probe according to the present invention.

Fig. 2 is a structural flow direction sectional view of a pressure measuring tube and a thermocouple of a composite three-hole pressure-temperature probe according to the present invention.

Fig. 3A to 3B are structural layout manners of a pressure measuring tube and a thermocouple of a composite three-hole pressure-temperature probe according to an embodiment of the present invention.

Fig. 4 is a structural normal sectional view of a temperature thermocouple stagnation housing of a composite three-hole pressure-temperature probe according to the present invention.

Fig. 5A is a layout of the lead-out section of the composite three-hole pressure-temperature probe according to the present invention.

Fig. 5B is a top view of fig. 5A.

Fig. 5C is a cross-sectional view of the thermocouple of fig. 5A.

FIG. 5D is a cross-sectional view of the pressure sensing tube of FIG. 5A.

Detailed Description

The preferred embodiment of the present invention will be described in detail below with reference to fig. 1 to 5.

As shown in fig. 1, the present invention provides a composite three-hole pressure-temperature probe, which comprises three pressure-pressure pipes, two total temperature thermocouples, two static pressure pipes and two static temperature thermocouples arranged inside a probe rod body 4, wherein the front end of the probe rod body 4 is a static parameter section 3, the middle section of the probe rod body 4 is connected with a lead-out section 5, the rear end of the probe rod body 4 is connected with a mounting seat positioning block 7, a transition section 2 is connected with a probe head 1 and the static parameter section 3, and the probe rod body 4 plays a role in wrapping all the pressure-pressure pipes and all the temperature thermocouples, and enhances the structural strength of the whole probe. The probe head 1 is provided with three pressure-measuring tubes and two total temperature thermocouples, the detection ends of the three pressure-measuring tubes and the two total temperature thermocouples are arranged on the probe head 1, and the pressure-measuring tubes and the total temperature thermocouples sequentially pass through the probe head 1, the transition section 2, the static parameter section 3 and the probe rod body 4 and finally extend out of the leading-out section 5. The detection ends of the two static pressure measuring tubes and the two static temperature thermocouples are arranged on the side wall of the static parameter section 3, and the static pressure measuring tubes and the static temperature thermocouples sequentially pass through the static parameter section 3 and the probe rod body 4 and finally stretch out of the leading-out section 5. All pressure measuring tubes and thermocouples extending out of the leading-out section 5 can be connected into a digital sensor array pressure testing module (DSA) and a distributed optical fiber temperature sensing system (DTS) through a pneumatic connector.

As shown in fig. 2, in an embodiment of the present invention, the end of the pressure measuring head 1 is wedge-shaped, the wedge angle of the wedge and the width of the end of the wedge can be adjusted according to specific structural dimensions, and the wedge angle is 10 ° to 30 °.

As shown in fig. 2 and fig. 3A to 3B, in an embodiment of the present invention, the probe head 1 is provided with three pressure-measuring tubes and two total-temperature thermocouples, wherein one pressure-measuring tube 9 and two total-

temperature thermocouples

13 and 14 are located at a wedge at the top end of the probe head 1, the pressure-measuring tube 9 is located in the middle of the wedge, and the two total-

temperature thermocouples

13 and 14 are symmetrically located at two sides of the pressure-measuring tube 9, so that it is ensured that symmetry of a deflection angle of the probe is not affected, and total temperature can be accurately obtained by algebraic superposition of the two symmetrical thermocouples. Specifically, as shown in fig. 3A and 3B, the probe head 1 is placed downward, the probe shaft body 4 is placed upward, and in the air flow direction, the total temperature thermocouple 13 is disposed on the left side, the pressure piezometer tube 9 is disposed in the middle, and the total temperature thermocouple 14 is disposed on the right side. As shown in fig. 2, the remaining two pressure and

piezometric tubes

8, 10 are located on the side walls of the tip taper of the probe head 1. The diameter of each pressure piezometer tube and the diameter of the total temperature thermocouple can be adjusted according to the specific structure size.

In one embodiment of the invention, as shown in figure 4, the probing ends of the

thermocouples

13 and 14 are not located on the top wedge surface of the probe head 1, but are provided with a stagnation cover 17. Specifically, the stagnation cover 17 reduces the supersonic air flow speed into the probe head 1 to a certain extent, so that the speed error is reduced to the allowable range of air flow Ma <0.2 to ensure that the total temperature thermocouple measures accurate total temperature of the air flow.

As shown in fig. 3A to 3B, in one embodiment of the present invention, the transition section 2 is a duckbill regular body, the cross section of the front end connected to the probe head 1 is a rectangle, and the cross section of the end connected to the static parameter section 3 is a circle, which is a square-to-circle structure. The duckbill profile functions as: the supersonic airflow passing through the profile can generate a series of weak oblique shock waves, and the oblique shock waves can enable the supersonic airflow to be decelerated until the supersonic speed is reduced to the subsonic speed. Because each oblique shock wave is weak, the supersonic air flow is nearly isentropically compressed through the oblique shock wave system. Therefore, the static pressure and the static temperature of the subsonic airflow on the static parameter section after passing through the transition section can be calculated. Meanwhile, due to the duckbill-shaped structural design of the transition section, the geometric size of the pressure measuring head is reduced as much as possible on the one hand, so that the interference of the pneumatic probe on the wind tunnel experiment of the impeller machinery is reduced, the geometric size of the probe rod body is increased on the one hand, and the stability of the pneumatic probe in supersonic airflow is improved.

As shown in fig. 2 and fig. 3A to 3B, in an embodiment of the present invention, the diameter of the static parameter section 3 is not more than 10mm, the two static

pressure measurement pipes

11 and 12 are arranged on the sidewall of the static parameter section 3 in a central symmetry manner around the central axis of the static parameter section 3, and the two

static temperature thermocouples

15 and 16 are arranged on the sidewall of the static parameter section 3 in a central symmetry manner around the central axis of the static parameter section 3. According to the static parameter section structure, the layout modes of the

static pressure piezometers

11 and 12 and the

static temperature thermocouples

15 and 16 are two schemes: as shown in fig. 3A, the

static temperature thermocouples

15, 16 are arranged in front of the

static pressure piezometers

11, 12 and closer to the probe head 1, and as shown in fig. 3B, the

static temperature thermocouples

15, 16 are arranged behind the

static pressure piezometers

11, 12 and further from the probe head 1. Specifically, the probe head part 1 is placed downwards, the probe rod body 4 is placed upwards, and along the air flow direction, the static pressure piezometer tube 11 is located at the upper position, the static pressure piezometer tube 12 is located at the lower position, the static temperature thermocouple 15 is located at the upper position, and the static temperature thermocouple 16 is located at the lower position.

As shown in fig. 1, in an embodiment of the present invention, the probe rod body 4 includes three portions, which are a front end, a middle section and a rear end, respectively, the front end, the middle section and the rear end form an n-shaped structure, and the geometric structure of the middle rod body between the static parameter section 3 and the leading-out section 5 is cylindrical, so as to form a cylindrical bypass flow for the incoming flow, thereby reducing the impact force of the air flow on the probe and enhancing the stability of the probe. The geometrical structure of the rear end rod body between the leading-out section 5 and the mounting seat positioning block 7 is a cuboid, so that the probe is mounted, and the probe pressure measuring head direction and the normal direction of the wind tunnel experiment piece are more favorably aligned.

In one embodiment of the invention, two reinforcing ribs 6 are used to increase the structural strength of the probe shaft body 4. The reinforcing ribs 6 are two metal plates with curved triangular edges, and are respectively and fixedly arranged between the front end and the middle section of the probe rod body 4 and two turning positions between the middle section and the rear end, two straight edges of the triangle are respectively welded on the probe rod body, and the curved edges of the triangle are not in contact with the probe rod body and face the direction of air flow. The purpose of designing for the curved edge of triangle-shaped towards the direction of air current is to form the water conservancy diversion effect to the air current, reduces the impact force of air current to the probe body of rod 4 inflection department to strengthen the structural strength of probe body of rod 4.

In one embodiment of the invention, the mounting seat positioning block 7 is a round cake-shaped metal block sleeved on a cylindrical metal rod, and is used for being nested into a groove on the wind tunnel probe holder through the positioning block so as to fix the probe rod body 4 and avoid shaking. The round cake shape is designed to facilitate the rotation of the probe rod body 4 in the groove of the wind tunnel probe stand.

As shown in fig. 5A, in one embodiment of the present invention, the leading-out section 5 is in the form of a hollow semicircular structure, the bottom of the leading-out section is a rectangular plane, the rectangular plane is connected with the probe shaft body 4, and the vertical section of the leading-out section 5 is semicircular. The temperature thermocouple and the pressure piezometer tube are respectively led out from the circular hole of the circular arc surface of the hollow semicircular structure and are connected with the pneumatic connector, the piezometer tube and the thermocouple are fixed through the semicircular structure, the relatively fine piezometer tube and the thermocouple can be protected, and the piezometer tube and the thermocouple are prevented from being bent, collided and wound. Specifically, as shown in fig. 5B, the temperature thermocouples are arranged in the front side in sequence, and the pressure piezometers are arranged in the rear side in sequence. As shown in fig. 5C, the row of the temperature thermocouple leading-out sections is sequentially provided with a static temperature thermocouple 15, a total temperature thermocouple 13, a total temperature thermocouple 14 and a static temperature thermocouple 16 from left to right. As shown in fig. 5D, the pressure-measuring pipe leading-out section in the row is sequentially provided with a static pressure-measuring pipe 11, pressure-measuring

pipes

8, 9 and 10, and a static pressure-measuring pipe 12 from left to right.

In the above embodiments of the present invention, the terms "upper", "lower", "left", "right", "front", and "rear" are used as references with respect to the directions shown in the drawings, and these terms are used for convenience of description only and do not represent limitations on specific embodiments of the present invention.

According to the invention, through ultrasonic wind tunnel calibration, in the actual measurement process, a pressure measurement system measures the pressure sensed by pressure measuring pipes 8-10 of a probe head 1, and the pressure is converted into a total pressure calibration coefficient C_ptSpeed calibration coefficient C_vAnd a direction characteristic calibration coefficient K_αAnd obtaining the total pressure, the static pressure, the Mach number and the deflection angle according to a calibration algorithm. The total temperature can be obtained through the algebraic average value of the

total temperature thermocouples

13 and 14, and the static temperature can be obtained through the electric signals output by the static temperature thermocouples 15-16 and the calibration relation. The speed can be converted by using the obtained total temperature, static temperature and Mach number.

The invention can simultaneously and simultaneously measure the pneumatic parameters of total temperature, static temperature, total pressure, static pressure, Mach number, two-dimensional flow velocity, deflection angle of airflow and the like of the airflow under the conditions of transonic velocity and supersonic velocity incoming flow, can be used for wind tunnel experiments of two-dimensional blade profiles of impeller machinery and other related fields, and can realize accurate measurement.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.

Claims

1. A composite three-hole pressure-temperature probe, comprising: the probe comprises three pressure-measuring tubes, two total-temperature thermocouples, two static pressure-measuring tubes and two static-temperature thermocouples, wherein the three pressure-measuring tubes, the two total-temperature thermocouples, the two static pressure-measuring tubes and the two static-temperature thermocouples are arranged in a probe rod body;

2. The composite three-hole pressure-temperature probe of claim 1, wherein the end of the pressure measuring head is wedge-shaped, and the wedge angle of the wedge is 10-30 °.

3. A composite three-hole pressure-temperature probe according to claim 2, wherein one pressure piezometer tube and two total thermo-couples are disposed at the top end wedge of the pressure measuring head, the pressure piezometer tube is located in the middle, the two total thermo-couples are symmetrically located at the two sides of the pressure piezometer tube, and the other two pressure piezometer tubes are respectively located at the two side walls of the top end wedge of the probe head.

4. A composite three-hole pressure-temperature probe as set forth in claim 1, wherein a stagnation cover is installed at a probing end of said total temperature thermocouple.

5. The composite three-hole pressure-temperature probe as claimed in claim 1, wherein the transition section is a duckbill-shaped regular body, the cross-section of the front end of the transition section connected to the probe head is a rectangle, and the cross-section of the end of the transition section connected to the static parameter section is a circle.

6. The composite three-hole pressure-temperature probe as claimed in claim 1, wherein the two static pressure-measuring tubes are arranged on the side wall of the static parameter section in a central symmetry manner around the central axis of the static parameter section, and the two static temperature thermocouples are arranged on the side wall of the static parameter section in a central symmetry manner around the central axis of the static parameter section.

7. A composite three-hole pressure-temperature probe as in claim 6, wherein said static parameter section has a diameter of 10mm or less.

8. A composite three-hole pressure-temperature probe as in claim 1, wherein said probe rod body comprises a front end, a middle section and a rear end, said front end, said middle section and said rear end forming an n-shaped structure, said middle section rod body between said static parameter section and said lead-out section having a cylindrical geometry, and said rear end rod body between said lead-out section and said mounting block having a rectangular geometry.

9. The composite three-hole pressure-temperature probe as claimed in claim 8, wherein the probe includes a reinforcing rib, the reinforcing rib is respectively disposed at a transition between the front end and the middle section of the probe rod body and at a transition between the middle section and the rear end of the probe rod body, the reinforcing rib has a cross section of a triangle with curved sides, two straight sides of the triangle respectively contact the probe rod body, the curved side of the triangle does not contact the probe rod body, and the curved side faces the direction of the gas flow.

10. A composite three-hole pressure-temperature probe according to claim 1, wherein the lead-out section is a hollow semicircular structure with a rectangular plane at the bottom, and a semicircular vertical section, the two total thermo-couples and the two static thermo-couples are arranged linearly at the lead-out section, the two total thermo-couples are arranged in the middle, the three pressure piezometers and the two static pressure piezometers are arranged linearly at the lead-out section, and the three pressure piezometers are arranged in the middle.