A multi-point steady-state measurement device with total temperature and total pressure measurement points arranged in back-to-back directions

Abstract

The present invention belongs to the technical field of flow field testing, and specifically relates to a multi-point steady-state measurement device with total temperature and total pressure measuring points arranged in back-to-back directions, which is composed of a head, a support rod, a pressure sensing hole, a temperature sensor, an insulating seal, a pressure channel, a pressure channel, and a temperature sensor cable. The head of the device is cylindrical, and has pressure sensing holes sparse in the middle and dense at both ends opened on the surface along the axial direction. The connection between the pressure sensing holes and the pressure channel adopts a minimally-damaged and smooth structural design. A flat groove is opened on the back of the head opposite to each pressure sensing hole, and the temperature sensor extends from one side of the flat groove and is located on the center line of the relative pressure sensing hole. The present invention can realize the simultaneous measurement of the multi-point steady-state total temperature and total pressure of the blade inlet, outlet, and inter-stage flow field in the impeller machine flow channel, and has the characteristics of a large insensitive angle for measuring airflow, high measurement accuracy, high reliability, and high spatial resolution.

Description

Technical Field

[0001] The present invention belongs to the technical field of total temperature and total pressure testing of flow fields, and specifically relates to a multi-point steady-state measuring device with total temperature and total pressure measuring points arranged in back-to-back order, which is suitable for simultaneous and accurate measurement of multi-point steady-state total temperature and total pressure in blade inlet, outlet and inter-stage flow fields in an impeller machinery flow channel. Background Art

[0002] When testing impellers such as compressors, turbines, pumps, blowers, and fans, it is usually necessary to simultaneously measure the steady-state total temperature and total pressure at multiple points in the flow channel, including the blade row inlet, outlet, and interstage. However, the mainstream direction of the blade row distribution along the blade height varies greatly, and the total temperature and total pressure also vary greatly. Therefore, it is very difficult to simultaneously measure the steady-state total temperature and total pressure at multiple points along the blade height direction. Existing measurement technologies have the following problems:

[0003] 1. Use a single-point total pressure probe to measure the total pressure at different positions with the help of a displacement mechanism installed on the casing. Also use a single-point total temperature probe to measure the total temperature at the same position on the streamline with the help of a displacement mechanism installed on the casing. When using a single-point total pressure probe and a single-point total temperature probe alone, on the one hand, the measurement time is long and the test cost is high. More importantly, the incoming flow conditions may change to a certain extent. On the other hand, the measurement point positions of different probes are affected by the positioning of the displacement mechanism, which will cause the two measurement positions to be different. The flow field parameters measured by the two probes are not on the same streamline, resulting in a huge error.

[0004] 2. The existing multi-point steady-state pressure measurement devices mainly include total pressure combs, which are generally composed of total pressure pipes with the same direction. The measurement error is large for flow fields with large changes in the incoming flow direction, and the total temperature cannot be measured at the same time.

[0005] 3. The existing steady-state pressure measurement device does not have a smooth transition in the pressure sensing hole. When the incoming flow angle is large, flow separation occurs, causing a certain total pressure loss, resulting in inaccurate measurement results.

[0006] 4. The existing steady-state temperature and pressure combination probe is a single-point measurement and cannot achieve multi-point simultaneous measurement. Moreover, the temperature sensor and pressure sensing hole are arranged on the windward side of the probe facing the incoming flow, but this requires a relatively large space on the probe surface, resulting in poor spatial resolution of flow field measurement, and the temperature and pressure measurement points are not on the same streamline, which will lead to large measurement errors. In addition, the temperature sensor is directly washed by the fluid and is easily damaged; it is easily affected by oil and dust in the flow field; the airflow insensitive angle is small, and when the pitch angle or deflection angle of the incoming flow to be measured is large, the airflow cannot be fully stagnant; at the same time, the heat exchange on the temperature sensor surface is insufficient, and the total temperature measurement error is large.

[0007] Due to the above problems, the existing measurement technology cannot measure the steady-state total temperature and total pressure at multiple points of the blade row inlet, outlet, and interstage flow field in the impeller machine flow channel, while researchers hope to obtain these parameters at the same time for design verification and diagnosis, so as to improve the design. Therefore, there is an urgent need for a multi-point steady-state total temperature and total pressure measurement device to achieve simultaneous and accurate measurement of the steady-state total temperature and total pressure at multiple points of the blade row inlet, outlet, and interstage flow field in the flow channel. Summary of the invention

[0008] The technical problems to be solved by the present invention are: single-point measurement is time-consuming and has high experimental costs, and it is impossible to ensure that the steady-state total temperature and total pressure measuring points are on the same streamline; the existing multi-point measurement device can only realize the measurement of steady-state total pressure, and cannot simultaneously measure the steady-state total temperature of multiple points; the pressure sensing hole structure of the existing pressure measurement device is unreasonable, the airflow insensitive angle is small, and the total pressure measurement loss is large; the existing steady-state temperature and pressure combination probe is large in size and low in spatial resolution, and cannot measure the steady-state total temperature and total pressure on the same streamline, causing measurement errors; the temperature sensor is facing the mainstream, is easy to be damaged, and is easily affected by oil and dust in the flow field. The airflow insensitive angle is small. When the pitch angle or deflection angle of the incoming flow to be measured is large, the airflow cannot be fully stagnant. At the same time, the heat exchange on the surface of the temperature sensor is insufficient, and the total temperature measurement error is large.

[0009] The present invention reasonably designs the position and size of the temperature sensor and the pressure sensing hole, and can realize the simultaneous measurement of multi-point steady-state total temperature and total pressure; the total pressure hole adopts a micro-loss and smooth structural design, which reduces the total pressure loss in a wider range of incoming flow angles and improves the measurement accuracy; abandons the traditional design concept of the total temperature device, and does not design it according to the method of the temperature sensor facing the mainstream and using a stagnation cover to stop the airflow to achieve total temperature measurement. Instead, based on the applicant's many years of research, it creatively proposes a layout and structural design in which the temperature sensor is facing the mainstream and is placed on the leeward side of the head of the device, and the temperature sensor is facing the pressure sensing hole, which can ensure the steady-state total temperature and total pressure measurement of the same streamline; effectively reduces the scouring of the temperature sensor by the airflow and the influence of oil droplets, dust, etc. mixed in the airflow on the temperature sensor, thereby improving the service life of the temperature sensor; effectively reduces the head size and improves the spatial resolution; strengthens the convective heat exchange between the airflow and the temperature sensor, and the temperature recovery coefficient is high and stable within a larger deflection angle range.

[0010] The technical solution of the present invention is:

[0011] 1. A multi-point steady-state measuring device with total temperature and total pressure measuring points arranged in back-to-back order, comprising a head (1), a support rod (2), a pressure sensing hole (3), a temperature sensor (4), a heat-insulating seal (5), a pressure-inducing channel (6), a pressure-inducing pipe (7), and a temperature sensor cable (8), characterized in that: a plurality of pressure sensing holes (3) with different axial positions are opened on the cylindrical surface of the head (1), and the directions of the pressure sensing holes (3) are respectively oriented toward the expected incoming flow direction and are connected to the pressure-inducing channel (6) in the head (1); the pressure-inducing channel (6) and the pressure-inducing pipe (7) are respectively connected at one end of the head (1) and the other end is led out from the tail end through the support rod (2); a plane groove is opened on the back of the cylinder opposite to each pressure sensing hole (3); the temperature sensor (4) extends from one side of the plane groove and is located on the center line of the corresponding pressure sensing hole (3) and faces away from the incoming flow; the temperature sensor cable (8) extends from the tail end of the support rod (2); the heat-insulating seal (5) is used to fix the temperature sensor (4) and plays a role of heat-insulating and insulating sealing.

[0012] 2. Furthermore, the diameter of the head (1) is 2 mm to 8 mm, the outer diameter of the pressure sensing hole (3) is 1 / 5 to 1 / 2 of the diameter of the head (1), and the diameter of the pressure-inducing channel (6) is 0.2 mm to 1 mm, which is not larger than the outer diameter of the pressure sensing hole (3).

[0013] 3. Furthermore, the pressure sensing holes (3) are distributed sparsely in the middle and densely at both ends along the axial direction of the head (1); the center lines of the pressure sensing holes (3) closest to the two ends of the head (1) are half the outer diameter of the pressure sensing holes (3) at both end surfaces; the axial distance between the center lines of the first pressure sensing hole (3) and the second pressure sensing hole (3) near the end is 1 to 4 mm, and the axial distance between the center lines of the remaining two adjacent holes is 2 to 6 mm; the directions of the center lines of the holes are not the same.

[0014] 4. Furthermore, the connection between the pressure sensing hole (3) and the pressure-inducing channel (6) adopts a ball socket plus rounded transition design to reduce the total pressure loss. The diameter of the ball socket is the outer diameter of the pressure sensing hole (3), the diameter of the transition rounded corner is 1 / 2 of the diameter of the ball socket, and the center line is orthogonal to the center line of the head (1).

[0015] 5. Furthermore, the depth of the planar groove is 1 / 5 to 1 / 2 of the diameter of the head (1), and the distance between the three surfaces and the temperature sensor (4) is not less than 0.5 mm. The temperature sensor (4) is located on the center line of the pressure sensing hole (3), and a thermocouple or a thermal resistor can be selected.

[0016] 6 Furthermore, through wind tunnel calibration experiments, the calibration curves of total temperature and total pressure at different Mach numbers and different deflection angles were determined, and the temperature and pressure signals obtained from actual measurements were processed to achieve simultaneous and accurate measurement of the steady-state total temperature and total pressure at multiple points including the blade inlet, outlet, and interstage in the flow channel of the impeller machinery, thereby increasing the life of the temperature sensor and the airflow insensitive angle range, and improving the measurement spatial resolution and measurement accuracy.

[0017] The beneficial effects of the present invention are:

[0018] 1. Compared with the existing steady-state total temperature and total pressure devices, the present invention can accurately and simultaneously measure the multi-point steady-state total temperature and total pressure distribution along the blade height between blade rows, realize the measurement of a larger flow angle range in different flow directions, and take into account the measurement of the steady-state total temperature and total pressure in the boundary layer of the flow channel end wall.

[0019] 2. Compared with the existing temperature and pressure combination probe, the present invention arranges the total temperature measurement and the total pressure measurement back to back, and the temperature sensor is directly opposite to the pressure sensing hole, which can ensure multi-parameter measurement of the same streamline; reduce the size of the device, improve the spatial resolution, and is suitable for simultaneous measurement of total temperature and total pressure in small gaps.

[0020] 3. Compared with the existing total pressure device, the total pressure hole of the present invention adopts a micro-loss and smooth structural design, without flow separation in a wide range of incoming flow angles, reducing total pressure loss and improving measurement accuracy.

[0021] 4. The temperature measuring end faces away from the incoming airflow, which effectively reduces the scouring of the temperature sensor by the airflow and the influence of oil droplets, dust, etc. in the airflow on the temperature sensor, thereby increasing the service life of the temperature sensor; effectively reduces the size of the head and improves the spatial resolution; strengthens the convection heat exchange between the airflow and the temperature sensor, and the temperature recovery coefficient is high and stable within a larger deflection angle range. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an implementation example 1 of the present invention.

[0023] Figure 2 yes Figure 1 Right view of .

[0024] Figure 3 It is an AA cross-sectional view of the first embodiment of the present invention.

[0025] Among them: 1-device head, 2-device support rod, 3-pressure sensing hole, 4-temperature sensor, 5-insulating seal, 6-pressure channel, 7-pressure pipe, 8-temperature sensor cable.

[0026] Figure 4 This is a schematic diagram of the implementation case 1 for measuring the flow field between compressor stages.

[0027] Figure 5 This is a schematic diagram of boundary layer measurement in implementation case 1.

[0028] Among them: 1-casing wall, 2-stator, 3-rotor, 4-stator, 5-hub wall, 6-device of the present invention, 7-boundary layer velocity type.

[0029] Figure 6 It is a structural schematic diagram of implementation case 2 of the present invention.

[0030] Among them: 1-device head, 2-device support rod, 3-pressure sensing hole, 4-temperature sensor, 5-insulating seal, 6-pressure channel, 7-pressure pipe, 8-temperature sensor cable.

[0031] Figure 7 This is a schematic diagram of the first implementation case for measuring the flow field between turbine stages.

[0032] Wherein: 1-casing wall, 2-stator, 3-rotor, 4-stator, 5-hub wall, 6-device of the present invention. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings 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.

[0034] Embodiment 1:

[0035] For the measurement of the steady-state total temperature and total pressure distribution along the same blade height between compressor stages, the measurement space is narrow, the boundary layer is thin, the mainstream changes greatly along the blade height direction, but the speed is relatively low. In order to ensure spatial resolution, a smaller lateral size of the device head and the diameter of the pressure measuring hole should be selected, and the temperature sensor can use a smaller bare wire thermocouple to ensure refined measurement and improve measurement accuracy. Therefore, the following implementation method can be adopted:

[0036] like Figures 1 to 3 The figure shows a schematic diagram of a multi-point steady-state measurement device with total temperature and total pressure measurement points arranged back to back, which is created by the present invention. Figure 4 It is a schematic diagram of the device of the present invention used for measuring the flow field between compressor stages. Figure 5This is a schematic diagram of compressor boundary layer measurement. The present embodiment introduces a multi-point steady-state measurement device with total temperature and total pressure measuring points arranged in back-to-back direction, which is composed of a head (1), a support rod (2), a pressure sensing hole (3), a thermocouple (4), a heat-insulating seal (5), a pressure channel (6), a pressure tube (7), and a temperature sensor cable (8). The device is characterized in that: the cylindrical surface of the head (1) is provided with five pressure sensing holes (3) with different axial positions, which are oriented toward the expected incoming flow direction and are connected to the pressure channel (6) in the head (1); the pressure channel (6) and the pressure tube (7) are respectively connected at one end of the head (1) and the other end is led out from the tail end through the support rod (2); a plane groove is provided on the back of the cylinder opposite to each pressure sensing hole (3); the thermocouple (4) extends from one side of the plane groove and is located on the center line of the corresponding pressure sensing hole (3) and faces away from the incoming flow; the temperature sensor cable (8) extends from the tail end of the support rod (2); the heat-insulating seal (5) is used to fix the thermocouple (4) and plays the role of heat-insulating and insulating sealing.

[0037] The diameter of the head (1) is 2 mm, the outer diameter of the pressure sensing hole (3) is 1 mm, and the diameter of the pressure-inducing channel (6) is 0.2 mm.

[0038] The pressure sensing holes (3) are distributed sparsely in the middle and densely at the two ends along the axial direction of the head (1); the center lines of the pressure sensing holes (3) closest to the two ends of the head (1) are 1 mm away from the two end surfaces; the axial distance between the center lines of the first pressure sensing hole (3) and the second pressure sensing hole (3) close to the end is 1 mm, and the axial distance between the center lines of the remaining two adjacent holes is 2 mm; the directions of the center lines of the holes are not the same.

[0039] The connection between the pressure sensing hole (3) and the pressure-inducing channel (6) adopts a ball socket with a radius of 0.5 mm and a fillet transition with a radius of 0.2 mm to reduce losses. The center line of the pressure sensing hole (3) is orthogonal to the center line of the device head (1).

[0040] The depth of the planar groove is 0.5 mm, and the distances between the three surfaces and the thermocouple (4) are all 0.2 mm. The thermocouple (4) is located on the center line of the pressure sensing hole (3).

[0041] The multi-point steady-state measurement device of the present invention, in which the total temperature and total pressure measurement points are arranged in reverse, can realize the simultaneous and accurate measurement of the multi-point steady-state total temperature and total pressure between compressor stages. The specific method of use is as follows:

[0042] Step 1: In a calibrated wind tunnel with known incoming Mach number and temperature, pass the incoming flow over the device head.

[0043] Step 2: Measure the pressure of the pressure sensing hole on the windward side of the device and the temperature of the temperature sensor on the leeward side under different working conditions.

[0044] Step 3: Based on the calibration data, determine the calibration curves of total temperature and total pressure at different Mach numbers and different deflection angles through data processing.

[0045] Step 4: When in use, the device of the present invention is inserted into the measured flow field, and data processing is performed on the pressure and temperature signals actually measured to achieve simultaneous and accurate measurement of the steady-state total temperature and total pressure at multiple points including the blade inlet, outlet, and interstage in the impeller machine flow channel.

[0046] Embodiment 2:

[0047] For the measurement of the steady-state total temperature and total pressure distribution along the same blade height between turbine stages, the mainstream velocity is relatively high. In order to ensure the strength of the measuring device, a larger lateral size of the device head and the diameter of the pressure measuring hole should be selected. The temperature sensor can use an armored thermal resistor to ensure refined measurement and improve strength. Therefore, the following implementation method can be adopted:

[0048] Figure 6 It is a structural schematic diagram of implementation case 2 of the present invention. Figure 7 The present invention is a schematic diagram of the device used to measure the flow field between turbine stages. This embodiment introduces a multi-point steady-state measurement device with total temperature and total pressure measurement points arranged in back-to-back order, which is composed of a head (1), a support rod (2), a pressure sensing hole (3), an armored thermal resistor (4), an insulating seal (5), a pressure channel (6), a pressure pipe (7), and a temperature sensor cable (8). It is characterized in that: the cylindrical surface of the head (1) is provided with 7 pressure sensing holes (3) at different axial positions, which are oriented toward the expected incoming flow direction and are connected to the pressure channel (6) in the head (1). The channel (6) and the pressure-leading tube (7) are respectively connected at one end of the head (1), and the other end is led out from the tail end through the support rod (2); a plane groove is opened on the back of the cylinder opposite to each pressure sensing hole (3), and the armored thermal resistor (4) extends from one side of the plane groove and is located on the center line of the corresponding pressure sensing hole (3) and faces away from the incoming flow. The temperature sensor cable (8) extends from the tail end of the support rod (2); the heat-insulating seal (5) is used to fix the armored thermal resistor (4) and plays a role of heat-insulating and insulating sealing.

[0049] The diameter of the head (1) is 4 mm, the outer diameter of the pressure sensing hole (3) is 1 / 2 of the diameter of the head (1), and the diameter of the pressure-inducing channel (6) is 1 mm.

[0050] The pressure sensing holes (3) are distributed sparsely in the middle and densely at both ends along the axial direction of the head (1); the center lines of the pressure sensing holes (3) closest to the two ends of the head (1) are half the outer diameter of the pressure sensing holes (3) at both end surfaces; the axial distance between the center lines of the first pressure sensing hole (3) and the second pressure sensing hole (3) near the end is 2 mm, and the axial distance between the center lines of the remaining two adjacent holes is 4 mm; the directions of the center lines of the holes are not the same.

[0051] The connection between the pressure sensing hole (3) and the pressure-inducing channel (6) adopts a ball socket with a radius of 1 mm and a fillet transition with a radius of 0.5 mm to reduce losses. The center line of the pressure sensing hole (3) is orthogonal to the center line of the device head (1).

[0052] The depth of the planar groove is 1 mm, and the distances between the three surfaces and the armored thermal resistor (4) are all 0.5 mm. The armored thermal resistor (4) is located on the center line of the pressure sensing hole (3).

[0053] After wind tunnel calibration experiments, calibration data is obtained, and data processing is performed to obtain the relationship between steady-state total temperature, total pressure, Mach number and incoming flow direction, which can achieve simultaneous and accurate measurement of steady-state total temperature and total pressure at multiple points between turbine stages.

[0054] Although the preferred embodiment has been described, various modifications or substitutions may be made to the embodiment without departing from the spirit and scope of the invention. Therefore, it should be understood that the present invention has been described in an illustrative manner rather than a restrictive manner.

Claims

1. A method for using a multi-point steady-state measuring device with total temperature and total pressure measuring points arranged in opposite directions to achieve simultaneous and accurate measurement of the total temperature and total pressure at multiple points between compressor stages, wherein the multi-point steady-state measuring device with total temperature and total pressure measuring points arranged in opposite directions to each other is structured as follows: the device comprises a head (1), a support rod (2), a pressure sensing hole (3), a temperature sensor (4), a heat-insulating seal (5), a pressure-inducing channel (6), a pressure-inducing pipe (7), and a temperature sensor cable (8), and is characterized in that: The cylindrical surface of the head (1) is provided with a plurality of pressure sensing holes (3) at different axial positions, the directions of which are respectively oriented toward the expected incoming flow direction and connected to the pressure induction channel (6) in the head (1). The pressure induction channel (6) and the pressure induction tube (7) are respectively connected at one end of the head (1), and the other end is led out from the tail end through the support rod (2); a plane groove is provided on the back of the cylinder opposite to each pressure sensing hole (3); a temperature sensor (4) extends from one side of the plane groove and is located on the center line of the corresponding pressure sensing hole (3) and faces away from the incoming flow; a temperature sensor cable (8) extends from the tail end of the support rod (2); a heat-insulating seal (5) is used to fix the temperature sensor (4) and plays a role of heat-insulating seal; The diameter of the head (1) is 1 mm to 8 mm, the outer diameter of the pressure sensing hole (3) is 1 / 8 to 1 / 2 of the diameter of the head (1), and the diameter of the pressure-inducing channel (6) is 0.2 mm to 1 mm, which is not larger than the outer diameter of the pressure sensing hole (3); The pressure sensing holes (3) are distributed sparsely in the middle and densely at the two ends along the axial direction of the head (1); the center lines of the pressure sensing holes (3) closest to the two ends of the head (1) are half the outer diameter of the pressure sensing holes (3) at both end surfaces; the axial distance between the center lines of the first pressure sensing hole (3) and the second pressure sensing hole (3) near the end is 1 to 4 mm; the axial distance between the center lines of the remaining two adjacent holes is 2 to 6 mm; and the directions of the center lines of the holes are not the same; The connection between the pressure sensing hole (3) and the pressure-inducing channel (6) adopts a ball socket plus rounded transition design to reduce the total pressure loss. The diameter of the ball socket is the outer diameter of the pressure sensing hole (3), the diameter of the transition rounded corner is 1 / 2 of the diameter of the ball socket, and the center line is orthogonal to the center line of the head (1); The depth of the planar groove is 1 / 5 to 1 / 2 of the diameter of the head (1), and the distance between the three surfaces and the temperature sensor (4) is not less than 0.5 mm. The temperature sensor (4) is located on the center line of the pressure sensing hole (3), and a thermocouple or a thermal resistor can be selected; The use steps are as follows: Step 1: in a calibrated wind tunnel with known incoming flow Mach number and temperature, allow the incoming flow to flow through the head of the device; Step 2: Measure the pressure of the pressure sensing hole on the windward side of the device and the temperature of the temperature sensor on the leeward side under different working conditions; The third step: determining the calibration curves of total temperature and total pressure at different Mach numbers and different deflection angles through data processing based on the data obtained by calibration; the fourth step: inserting the device of the present invention into the measured flow field when in use, performing data processing on the pressure and temperature signals obtained from the actual measurement, and realizing simultaneous and accurate measurement of the steady-state total temperature and total pressure at multiple points including the blade inlet, outlet and interstage in the impeller machinery flow channel.

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