A multi-point temperature measurement system and method under rotating conditions

Abstract

This invention belongs to the field of temperature measurement technology and provides a multi-point temperature measurement system and method under rotational conditions. The system includes: a temperature difference measurement subsystem, a compensated temperature measurement subsystem, and a power supply system. The temperature difference measurement subsystem includes: two module integration boxes, an ADAM-4520 signal conversion module, and a computer. The compensated temperature measurement subsystem includes: two thermocouple junction boxes. The power supply system includes: a 24V DC power supply and a slip ring. This invention improves the measurement accuracy of cold junction compensated temperature by using three platinum resistance thermometers for temperature data acquisition; it improves experimental efficiency by introducing free-connection terminals; and by using two module integration boxes, it expands the total number of ADAM-4118 analog input modules to 32 and the number of temperature measurement points to 256, meeting the requirements for multi-point temperature measurement under rotational conditions.

Description

Technical Field

[0001] This invention relates to the field of temperature measurement technology, and in particular to a multi-point temperature measurement system and method under rotating conditions. Background Technology

[0002] With the continuous improvement of modern aero-engine performance, turbine inlet temperatures are also constantly rising. Coupled with the high-speed operation of turbine rotor components, turbine rotor blades face severe challenges from high temperature, high pressure, and high centrifugal loads. The target turbine inlet temperature for the latest generation of aero-engines has exceeded 2000K, significantly higher than the upper temperature resistance limit of new high-temperature alloy oxide dispersion alloys. Therefore, in addition to continuing the research and development of new high-temperature resistant metal materials, adopting efficient cooling technology is an inevitable choice to compensate for the temperature difference. Efficient cooling designs for turbine blades typically employ a composite cooling scheme, combining internal and external cooling. Internal cooling requires the installation of complex flow channels and various cooling enhancement structures within the blade, such as baffles, ribs, and double walls. External cooling requires the installation of several overflow holes on the blade surface. In actual operation, cooling air is supplied to the internal cooling channel through the air inlet at the blade root tenon, cooling the inner wall surface before flowing out through the overflow holes on the blade surface and the top dust removal hole. The cold air flowing out from the overflow holes on the blade surface forms a protective film on its surface, which serves to isolate the high-temperature combustion gases. In recent years, thermal barrier coating technology has also been applied to the thermal protection of turbine blade surfaces, further improving the temperature resistance of blades along with internal cooling and film cooling. Accurate temperature information is crucial for the research of efficient turbine blade cooling. Thermocouple temperature measurement has high accuracy and reliability and is widely used in experiments. As the principle of thermocouple temperature measurement shows, cold junction compensation is necessary to obtain the temperature value of the measured point. Compensation under static conditions is relatively easy to achieve; in experiments, the cold junction is usually placed in an ice bath containing an ice-water mixture to maintain it at 0°C, and the temperature value of the measured point can be directly read by consulting the calibration table of the corresponding thermocouple model. However, thermocouple temperature measurement of rotating experimental specimens faces the problem of signal transmission between static and dynamic states. Due to the limitation of the number of slip ring channels, if the temperature compensation end is placed on the external static side, only a few thermocouple millivolt signals can be extracted, and as an analog signal, it is highly susceptible to interference during dynamic and static transmission. Therefore, to ensure both the quantity and quality of temperature signals, the temperature compensation terminal is typically rotated with the experimental specimen. The thermocouple millivolt signal is first converted to a digital signal, and then transmitted to the data acquisition system on the stationary side via a slip ring. However, the temperature compensation terminal on the rotating side is no longer suitable for ice bath insulation; in practice, the cold junction temperature correction method is often used instead. This method works by first measuring the cold junction temperature as the compensation temperature, then consulting a calibration table to obtain the corresponding millivolt potential difference. This millivolt potential difference is then added to the millivolt potential difference measured by the thermocouple to obtain the total millivolt potential difference. Finally, the calibration table is consulted to determine the temperature value corresponding to the total millivolt potential difference, which is the temperature of the point to be measured. Since the compensation temperature is no longer kept at 0℃ in this method, it will change with the ambient temperature during the experiment; therefore, improving the measurement accuracy of the compensation temperature is a crucial consideration. In addition, although the thermocouple millivolt signal can be converted to a digital signal by a thermocouple input module that rotates with the experimental specimen, and then the slip ring completes the dynamic-to-static conversion output, this method is not always feasible.However, the high-speed centrifugal load severely limits the number of modules and their installation locations, restricting the increase in the number of temperature measurement points on the experimental platform. Some teams have conducted in-depth research on rotating heat transfer in turbine blades, employing a disk-stacking design for their temperature compensation device, which uses a DS18B20 chip for internal temperature measurement and compensation. However, the measurement accuracy of this chip is only ±0.5K. In actual use, the temperature rise caused by bearing rotation is conducted along the shaft to the temperature compensation device, and the resulting non-uniform temperature field further reduces the measurement accuracy of the compensated temperature. Due to space constraints, the connection between the temperature-sensing thermocouple bundle and the signal wire is a single-point connection using pin-type terminals, resulting in a long wiring time during experimental preparation. Furthermore, the disk-stacking structure also limits the number of thermocouple input modules that can be installed, with a maximum of only 108 temperature measurement points. If a thermocouple input module malfunctions and needs replacement, this structure also significantly increases the difficulty of disassembling and replacing the module.

[0003] Although recent upgrades to the experimental platform have increased the maximum number of temperature measurement points to 192, the temperature compensation device still uses a tray-stacking design. The expansion of thermocouple input modules and measurement points is achieved only by increasing the number of stacked module mounting trays and the radial dimensions. This has not fundamentally solved the problems of limited measurement points, small module installation space, and difficulty in replacing faulty components. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a multi-point temperature measurement system and method under rotating conditions, which can improve the accuracy of temperature compensation, expand the wiring space, improve experimental efficiency, and increase the number of temperature measurement points.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A multi-point temperature measurement system in a rotating state includes: a temperature difference measurement subsystem, a compensated temperature measurement subsystem, and a power supply system; the temperature difference measurement subsystem includes: two module integration boxes, an ADAM-4520 signal conversion module, and a computer; the compensated temperature measurement subsystem includes: two thermocouple junction boxes; the power supply system includes: a 24V DC power supply and a slip ring; the module integration box includes: sixteen ADAM-4118 analog input modules, a square enclosure, two upper lead pipes for the integration box, and two lower lead pipes for the integration box. The thermocouple junction box includes: a first platinum resistance thermometer, a second platinum resistance thermometer, a third platinum resistance thermometer, an upper lead tube for the junction box, a lower lead tube for the junction box, a cylindrical housing, an ADAM-4015 resistance temperature detection module, and several free-connection terminals; the slip ring includes: a first rotor end interface, a second rotor end interface, a third rotor end interface, a fourth rotor end interface, a fifth rotor end interface, a sixth rotor end interface, a first stator end interface, a second stator end interface, a third stator end interface, a fourth stator end interface, a fifth stator end interface, and a sixth stator end interface;

[0007] Two upper and two lower integrated box lead-in pipes are located on the left and right sides of the square box; the upper and lower junction box lead-in pipes are located on the side of the cylindrical box; the first end of the free terminal is connected to the temperature measuring point on the test piece via a thermocouple bundle through the upper and lower junction box lead-in pipes; the second end of the free terminal is connected to the independent differential input channels of all ADAM-4118 analog input modules via a signal wire bundle divided into four equal paths through the upper, lower, and integrated box lead-in pipes; the DATA+ and DATA- terminals of all ADAM-4118 analog input modules are connected in parallel to each other, and two signal wires are led out to connect to the first rotor end interface and the second rotor end interface respectively; the first stator end interface and the second stator end interface are connected to the DATA+ and DATA- terminals of the ADAM-4520 signal conversion module respectively; the ADAM-4520 signal conversion module... The RS-232 data output channel of the 0 signal conversion module is connected to the computer; the first platinum resistance, the second platinum resistance, and the third platinum resistance are respectively connected to the three independent data input channels of the ADAM-4015 resistance temperature detection module; the DATA+ and DATA- terminals of the ADAM-4015 resistance temperature detection module are respectively connected to the third rotor end interface and the fourth rotor end interface; the third stator end interface and the fourth stator end interface are respectively connected to the DATA+ and DATA- terminals of the ADAM-4520 signal conversion module; the positive and negative terminals of the 24V DC power supply are connected to the fifth stator end interface and the sixth stator end interface through power supply wires; the +Vs and GND terminals of the ADAM-4015 resistance temperature detection module are connected in parallel with the +Vs and GND terminals of all ADAM-4118 analog input modules, and two power supply wires are led out to connect to the fifth rotor end interface and the sixth rotor end interface respectively; the two module integration boxes are arranged symmetrically based on the rotation axis;

[0008] The ADAM-4118 analog input module is used to convert the temperature measurement millivolt analog signal transmitted by the thermocouple bundle into an RS-485 digital signal; the ADAM-4015 resistance temperature detection module is used to convert the resistance temperature signals of the first platinum resistance thermometer, the second platinum resistance thermometer, and the third platinum resistance thermometer into RS-485 digital signals; the slip ring is used to transmit the RS-485 digital signals output by the ADAM-4118 analog input module and the ADAM-4015 resistance temperature detection module to the ADAM-4520 signal conversion module; the ADAM-4520 signal conversion module is used to convert the RS-485 digital signals output by the ADAM-4118 analog input module and the ADAM-4015 resistance temperature detection module into RS-232 signals, and transmit the RS-232 signals to the computer.

[0009] Preferably, the module integration box further includes: a support partition, a rear cover plate, a square box cover plate, four 4118 lower silicone pads and four 4118 upper silicone pads;

[0010] The rear cover is located on the rear side of the square box; four 4118 lower silicone pads are attached to the bottom groove of the square box; sixteen ADAM-4118 analog input modules are divided into four groups and fixed on the four 4118 lower silicone pads; four 4118 upper silicone pads are attached to the upper side of the four groups of ADAM-4118 analog input modules; the support partition is fixed on the four 4118 upper silicone pads; and the square box cover is fixed on the upper side of the square box.

[0011] Preferably, the thermocouple junction box further includes: a heat insulation pad, a first heat insulation mounting base, a second heat insulation mounting base, a third heat insulation mounting base, a 4015 lower silicone pad, a 4015 upper silicone pad, a pressure plate, a pressure pad, and a round box cover.

[0012] The heat insulation pad is attached to the bottom outer side of the cylindrical box; the 4015 lower silicone pad is attached to the inner bottom groove of the cylindrical box; the ADAM-4015 resistance temperature detection module is fixed on the 4015 lower silicone pad; the 4015 upper silicone pad is attached to the upper side of the ADAM-4015 resistance temperature detection module; the clamping plate is fixed on the 4015 upper silicone pad; the clamping pad is attached to the upper side of the extension column of the clamping plate; the cylindrical box cover is fixed on the clamping pad; the first heat insulation mounting base, the second heat insulation mounting base, and the third heat insulation mounting base are all fixed to the side of the cylindrical box; the first platinum resistance thermometer, the second platinum resistance thermometer, and the third platinum resistance thermometer are respectively fixed... The platinum resistance thermometers are fixed on the first, second, and third heat-insulating mounting bases. From a top-down view, the angle between the first and third platinum resistance thermometers and the center of the cylindrical housing is 180 degrees. From a top-down view, the angle between the first and second platinum resistance thermometers and the center of the cylindrical housing is 120 degrees. From a top-down view, the angle between the second and third platinum resistance thermometers and the center of the cylindrical housing is 60 degrees. The distance from the center of the first platinum resistance thermometer to the bottom of the cylindrical housing is one-quarter of the internal height of the housing. The distance from the center of the second platinum resistance thermometer to the bottom of the cylindrical housing is one-half of the internal height of the housing. The distance from the center of the third platinum resistance thermometer to the bottom of the cylindrical housing is three-quarters of the internal height of the housing.

[0013] Preferably, the first platinum resistance, the second platinum resistance, and the third platinum resistance are all platinum resistances with Class A precision.

[0014] Preferably, the free-connecting terminal block has a multi-row plug-in structure.

[0015] Preferably, the signal wire is a Teflon-plated silver-shielded wire.

[0016] Preferably, the first heat-insulating mounting base, the second heat-insulating mounting base, and the third heat-insulating mounting base are all made of G11 epoxy glass fiber.

[0017] Preferably, the material of the heat insulation pad is polytetrafluoroethylene.

[0018] Preferably, a multi-point temperature measurement method under rotation includes:

[0019] The first temperature measurement value of the first platinum resistance, the second temperature measurement value of the second platinum resistance, and the third temperature measurement value of the third platinum resistance are collected, and the average value of the first temperature measurement value, the second temperature measurement value, and the third temperature measurement value is calculated to obtain the compensation temperature.

[0020] Based on the type of thermocouple used, the reference millivolt value is obtained by looking up the millivolt value that matches the compensation temperature in the preset calibration table.

[0021] The multi-point millivolt values ​​of the thermocouple bundle are collected to obtain the temperature difference millivolt value;

[0022] The corrected millivolt value is obtained by calculating the algebraic sum of the reference millivolt value and the temperature difference millivolt value.

[0023] Based on the type of thermocouple used, the temperature value that matches the calibration millivolt value in the preset calibration table is looked up to obtain the actual temperature of the target test piece temperature measurement point.

[0024] The present invention discloses the following technical effects:

[0025] This invention provides a multi-point temperature measurement system and method under rotational conditions. By setting up three platinum resistance thermometers for temperature data acquisition, it solves the problem of low accuracy of single-point temperature measurement chips in traditional compensated temperature measurements, and achieves real-time high-precision compensation for thermocouple temperature measurement. By setting up a thermocouple junction box independent of the rotation axis and introducing free wiring terminals, it solves the problem of long time consumption for single-point wiring using pin-type terminals, thereby improving experimental efficiency. By using two module integration boxes independent of the rotation axis, the total number of ADAM-4118 analog input modules installed is expanded to 32 and the number of temperature measurement points is expanded to 256, solving the problem that the maximum number of temperature measurement points in the traditional disc-type stacked structure is only 108, and realizing the expansion of temperature measurement points. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a structural diagram of the temperature difference measurement subsystem provided in an embodiment of the present invention;

[0028] Figure 2 This is a structural diagram of the compensated temperature measurement subsystem provided in an embodiment of the present invention;

[0029] Figure 3 This is a structural diagram of an electronic power supply system provided in an embodiment of the present invention;

[0030] Figure 4 Exploded view of the thermocouple junction box of the compensated temperature measurement subsystem provided in this embodiment of the invention;

[0031] Figure 5An exploded view of the integrated box of the temperature difference measurement subsystem module provided in an embodiment of the present invention;

[0032] Figure 6 A cross-sectional view of the compensated temperature measurement subsystem provided in an embodiment of the present invention;

[0033] Figure 7 A diagram showing the circumferential positional relationship of the three platinum resistance thermometers installed in the thermocouple junction box of the compensated temperature measurement subsystem provided in this embodiment of the invention.

[0034] Figure 8 A diagram showing the height relationship of the three platinum resistance thermometers installed in the thermocouple junction box of the compensated temperature measurement subsystem provided in this embodiment of the invention.

[0035] Figure 9 This is a flowchart of the data acquisition and processing algorithm provided in an embodiment of the present invention;

[0036] Figure 10 A device diagram of the ADAM-4118 analog input module provided in an embodiment of the present invention;

[0037] Figure 11 A schematic diagram of the ADAM-4015 resistance temperature detection module provided in an embodiment of the present invention;

[0038] Figure 12 A device diagram of the ADAM-4520 signal conversion module provided in an embodiment of the present invention;

[0039] Figure 13 A diagram of a 24V DC power supply device provided in an embodiment of the present invention;

[0040] Explanation of reference numerals in the attached figures:

[0041] 1- Cylindrical housing, 2- Square housing, 3- ADAM-4118 analog input module, 4- Slip ring, 5- First rotor end interface, 6- Second rotor end interface, 7- First stator end interface, 8- Second stator end interface, 9- ADAM-4520 signal conversion module, 10- Computer, 11- First platinum resistance thermometer, 12- Second platinum resistance thermometer, 13- Third platinum resistance thermometer, 14- ADAM-4015 resistance temperature detection module, 15- Third rotor end interface, 16- Fourth rotor end interface, 17- Third stator end interface, 18- Fourth stator end interface, 19- Fifth rotor end interface, 20- Sixth rotor end interface, 2 1-Fifth stator terminal interface, 22-Sixth stator terminal interface, 23-24V DC power supply, 24-Insulation pad, 25-First insulation mounting base, 26-Second insulation mounting base, 27-Third insulation mounting base, 28-Lower lead pipe of junction box, 29-Upper lead pipe of junction box, 30-Lower silicone pad of 4015, 31-Upper silicone pad of 4015, 32-Pressure plate, 33-Pressure pad, 34-Round box cover, 35-Rear cover, 36-Lower lead pipe of integrated box, 37-Upper lead pipe of integrated box, 38-Lower silicone pad of 4118, 39-Upper silicone pad of 4118, 40-Support partition, 41-Square box cover, TS-Test piece to be measured temperature. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The purpose of this invention is to provide a multi-point temperature measurement system and method under rotating conditions, which improves the accuracy of temperature compensation, expands the wiring space, improves experimental efficiency, and increases the number of temperature measurement points.

[0044] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Figure 1 This is a structural diagram of the temperature difference measurement subsystem provided in an embodiment of the present invention. Figure 2 This is a structural diagram of the compensated temperature measurement subsystem provided in an embodiment of the present invention. Figure 3 This is a structural diagram of an electronic power supply system provided in an embodiment of the present invention. Figure 4 This is an exploded view of the thermocouple junction box of the compensated temperature measurement subsystem provided in an embodiment of the present invention. Figure 5 An exploded view of the integrated box of the temperature difference measurement subsystem module provided in an embodiment of the present invention, as shown below. Figures 1 to 5 As shown, this invention provides a multi-point temperature measurement system in a rotating state, including: a temperature difference measurement subsystem, a compensated temperature measurement subsystem, and a power supply system; the temperature difference measurement subsystem includes: two module integration boxes, an ADAM-4520 signal conversion module 9, and a computer 10; the compensated temperature measurement subsystem includes: two thermocouple junction boxes; the power supply system includes: a 24V DC power supply 23 and a slip ring 4; the module integration box includes: sixteen ADAM-4118 analog input modules 3, a square box 2, two upper lead pipes 37 and two lower lead pipes 36; the thermocouple junction box package Includes: a first platinum resistance thermometer 11, a second platinum resistance thermometer 12, a third platinum resistance thermometer 13, an upper lead tube 29 for the junction box, a lower lead tube 28 for the junction box, a cylindrical housing 1, an ADAM-4015 resistance temperature detection module 14, and several free wiring terminals; the slip ring 4 includes: a first rotor end interface 5, a second rotor end interface 6, a third rotor end interface 15, a fourth rotor end interface 16, a fifth rotor end interface 19, a sixth rotor end interface 20, a first stator end interface 7, a second stator end interface 8, a third stator end interface 17, a fourth stator end interface 18, a fifth stator end interface 21, and a sixth stator end interface 22;

[0046] Two integrated box upper lead pipes 37 and two integrated box lower lead pipes 36 are arranged on the left and right sides of the square box 2; the junction box upper lead pipe 29 and junction box lower lead pipe 28 are arranged on the side of the cylindrical box 1; the first end of the free terminal is connected to the temperature measuring point on the test piece TS to be measured by means of a thermocouple bundle through the junction box upper lead pipe 29 and junction box lower lead pipe 28; the second end of the free terminal is connected to the test piece TS by means of a signal wire bundle that is evenly divided into four paths through the junction box upper lead pipe 29, junction box lower lead pipe 28, and integrated box upper lead pipe 37. The integrated box's lower lead-in pipe 36 is connected to the independent differential input channels of all ADAM-4118 analog input modules 3; the DATA+ and DATA- terminals of all ADAM-4118 analog input modules 3 are connected in parallel to each other, and two signal wires are led out to connect to the first rotor end interface 5 and the second rotor end interface 6 respectively; the first stator end interface 7 and the second stator end interface 8 are connected to the DATA+ and DATA- terminals of the ADAM-4520 signal conversion module 9 respectively; the ADAM-4520 signal conversion... The RS-232 data output channel of module 9 is connected to computer 10; the first platinum resistance thermometer 11, the second platinum resistance thermometer 12, and the third platinum resistance thermometer 13 are respectively connected to the three independent data input channels of ADAM-4015 resistance temperature detection module 14; the DATA+ and DATA- terminals of ADAM-4015 resistance temperature detection module 14 are respectively connected to the third rotor end interface 15 and the fourth rotor end interface 16; the third stator end interface 17 and the fourth stator end interface 18 are respectively connected to the ADAM-4520 signal converter. The DATA+ and DATA- terminals of module 9 are connected; the positive and negative terminals of the 24V DC power supply 23 are connected to the fifth stator terminal interface 21 and the sixth stator terminal interface 22 via power supply wires; the +Vs and GND terminals of the ADAM-4015 resistance temperature detection module 14 are connected in parallel with the +Vs and GND terminals of all ADAM-4118 analog input modules 3, and two power supply wires are led out to connect to the fifth rotor terminal interface 19 and the sixth rotor terminal interface 20 respectively; the two module integration boxes are arranged symmetrically based on the rotation axis;

[0047] The ADAM-4118 analog input module 3 converts the temperature measurement millivolt analog signal transmitted by the thermocouple bundle into an RS-485 digital signal; the ADAM-4015 resistance temperature detection module 14 converts the resistance temperature signals of the first platinum resistance thermometer 11, the second platinum resistance thermometer 12, and the third platinum resistance thermometer 13 into RS-485 digital signals; the slip ring 4 transmits the RS-485 digital signals output by the ADAM-4118 analog input module 3 and the ADAM-4015 resistance temperature detection module 14 to the ADAM-4520 signal conversion module 9; the ADAM-4520 signal conversion module 9 converts the RS-485 digital signals output by the ADAM-4118 analog input module 3 and the ADAM-4015 resistance temperature detection module 14 into RS-232 signals, and transmits the RS-232 signals to the computer 10.

[0048] refer to Figure 5 The modular integration box also includes: a support partition 40, a rear cover 35, a square box cover 41, four 4118 lower silicone pads 38 and four 4118 upper silicone pads 39.

[0049] The rear cover plate 35 is located on the rear side of the square box 2; four 4118 lower silicone pads 38 are attached to the bottom groove of the square box 2; sixteen ADAM-4118 analog input modules 3 are divided into four groups and fixed on the four 4118 lower silicone pads 38; four 4118 upper silicone pads 39 are attached to the upper side of the four groups of ADAM-4118 analog input modules 3; the support partition 40 is fixed on the four 4118 upper silicone pads 39; and the square box cover plate 41 is fixed on the upper side of the square box 2.

[0050] refer to Figure 4 , Figure 6 , Figure 7 as well as Figure 8 The thermocouple junction box also includes: a heat insulation pad 24, a first heat insulation mounting base 25, a second heat insulation mounting base 26, a third heat insulation mounting base 27, a lower silicone pad 30 for 4015, an upper silicone pad 31 for 4015, a pressure plate 32, a pressure pad 33, and a round box cover 34.

[0051] The heat insulation pad 24 is attached to the outer bottom of the cylindrical box 1; the lower silicone pad 30 of 4015 is attached to the groove on the inner bottom surface of the cylindrical box 1; the ADAM-4015 resistance temperature detection module 14 is fixed on the lower silicone pad 30 of 4015; the upper silicone pad 31 of 4015 is attached to the upper side of the ADAM-4015 resistance temperature detection module 14; the clamping plate 32 is fixed on the upper silicone pad 31 of 4015; the clamping pad 33 is attached to the upper side of the extension column of the clamping plate 32; the round box cover 34 is fixed on the clamping pad 33; the first heat insulation mounting base 25, the second heat insulation mounting base 26, and the third heat insulation mounting base 27 are all fixed to the side of the cylindrical box 1; the first platinum resistance thermometer 11, the second platinum resistance thermometer 12, and the third platinum resistance thermometer 13 are respectively Fixed on the first heat-insulating mounting base 25, the second heat-insulating mounting base 26, and the third heat-insulating mounting base 27; from a top-view perspective, the angle between the first platinum resistance thermometer 11, the third platinum resistance thermometer 13 and the center of the cylindrical box 1 is 180 degrees; from a top-view perspective, the angle between the first platinum resistance thermometer 11, the second platinum resistance thermometer 12 and the center of the cylindrical box 1 is 120 degrees; from a top-view perspective, the angle between the second platinum resistance thermometer 12, the third platinum resistance thermometer 13 and the center of the cylindrical box 1 is 60 degrees; the distance from the center of the first platinum resistance thermometer 11 to the bottom of the cylindrical box 1 is one-quarter of the internal height of the box; the distance from the center of the second platinum resistance thermometer 12 to the bottom of the cylindrical box 1 is one-half of the internal height of the box; the distance from the center of the third platinum resistance thermometer 13 to the bottom of the cylindrical box 1 is three-quarters of the internal height of the box.

[0052] Preferably, the first platinum resistance 11, the second platinum resistance 12, and the third platinum resistance 13 are all platinum resistances with Class A precision.

[0053] Specifically, the free-connecting terminal block has a multi-row plug-in structure.

[0054] Preferably, the signal wire is a Teflon-plated silver-shielded wire.

[0055] Specifically, the materials of the first heat insulation mounting base 25, the second heat insulation mounting base 26, and the third heat insulation mounting base 27 are all G11 epoxy glass fiber.

[0056] Preferably, the material of the heat insulation pad 24 is polytetrafluoroethylene.

[0057] refer to Figure 9 A method for multi-point temperature measurement under rotating conditions, comprising:

[0058] The first temperature measurement value of the first platinum resistance 11, the second temperature measurement value of the second platinum resistance 12, and the third temperature measurement value of the third platinum resistance 13 are collected, and the average value of the first temperature measurement value, the second temperature measurement value, and the third temperature measurement value is calculated to obtain the compensation temperature.

[0059] Based on the type of thermocouple used, look up the millivolt value that matches the compensation temperature in the preset calibration table to obtain the reference millivolt value;

[0060] Multi-point millivolt values ​​of the thermocouple bundle are collected to obtain the temperature difference millivolt value;

[0061] Calculate the algebraic sum of the reference millivolt value and the temperature difference millivolt value to obtain the corrected millivolt value;

[0062] Based on the type of thermocouple used, the temperature value that matches the calibration millivolt value in the preset calibration table is looked up to obtain the actual temperature of the target test piece at the point to be measured.

[0063] refer to Figure 10 and Figure 11 One end of the thermocouple bundle is connected to the temperature measuring point on the test piece TS, and the other end is introduced into the cylindrical housing 1 through the upper lead tube 29 and the lower lead tube 28 of the junction box and connected to one end of several free terminals; one end of the signal wire bundle is connected to the 128 independent differential input channels of the sixteen ADAM-4118 analog input modules 3, and the other end is divided into four signal sub-bundles that are led out of the square housing 2 from the upper lead tube 37 and the lower lead tube 36 of the two integrated boxes; the four signal sub-bundles leading out of the square housing 2 are connected to the upper lead tube 2 of the junction box. 9 and the junction box lower lead pipe 28 are introduced into the cylindrical box 1 and connected to the other end of several free wiring terminals; the data output channels DATA+ and DATA- of the sixteen ADAM-4118 analog input modules 3 are connected in parallel to each other and two signal wires are led out, leading out from the round hole in front of the square box 2 and connected to the first rotor end interface 5 and the second rotor end interface 6 of the slip ring 4; the first platinum resistance 11, the second platinum resistance 12 and the third platinum resistance 13 are respectively connected to the three independent data input channels of the ADAM-4015 resistance temperature detection module 14.

[0064] refer to Figure 10 , Figure 11 , Figure 12 as well as Figure 13The two integrated box upper lead tubes 37 and the two integrated box lower lead tubes 36 are used to lead the four signal sub-hauls from the sixteen ADAM-4118 analog input modules 3 (a total of 128 independent differential channels) out of the square box 2; the junction box upper lead tube 29 and the junction box lower lead tube 28 are used to lead the thermocouple bundle from the test piece TS and the four signal sub-hauls from the square box 2 into the cylindrical box 1; the cylindrical box 1 is used to install the first platinum resistance thermometer 11, the second... The system includes a second platinum resistance thermometer 12, a third platinum resistance thermometer 13, an ADAM-4015 resistance temperature sensing module 14, and space for several free-connection terminals; sixteen ADAM-4118 analog input modules 3 are used to convert the temperature measurement millivolt analog signals transmitted by the thermocouple bundle into RS-485 digital signals; a square enclosure 2 is used to install the sixteen ADAM-4118 analog input modules 3; and a slip ring 4 is used for the 24V DC power supply 23 and the ADAM-4118 analog input modules. The ADAM-4015 resistance temperature detection module 14 is used for power supply current and RS-485 digital signal transmission between the input module 3 and the input module 14; the ADAM-4520 signal conversion module 9 is used to convert the RS-485 digital signal to an RS-232 signal and transmit the RS-232 signal to the computer 10; the computer 10 is used for experimental state control and temperature data acquisition; the first platinum resistance thermometer 11 is used to measure the temperature of the first point inside the cylindrical box 1; the second platinum resistance thermometer 12 is used to measure the temperature of the second point inside the cylindrical box 1; the third platinum resistance thermometer 13 is used to measure the temperature of the third point inside the cylindrical box 1; the ADAM-4015 resistance temperature detection module 14 is used to acquire the resistance temperature signals of the first platinum resistance thermometer 11, the second platinum resistance thermometer 12, and the third platinum resistance thermometer 13 and convert them into RS-485 digital signals; the 24V DC power supply 23 is used to power the ADAM-4118 analog input module 3 and the ADAM-4015 resistance temperature detection module 14.

[0065] Specifically, the support partition 40 provides stable support for the four sets of ADAM-4118 analog input modules 3 to counteract the rotational centrifugal force; the rear cover 35 facilitates the installation of the four sets of ADAM-4118 analog input modules 3 and the subsequent maintenance of the connected signal wires.

[0066] Preferably, the heat insulation pad 24 is used to isolate the experimental platform from conducting heat to the thermocouple junction box; the clamping plate 32 is used to fasten the ADAM-4015 resistance temperature detection module 14 to resist the centrifugal force of rotation; the first heat insulation mounting base 25, the second heat insulation mounting base 26 and the third heat insulation mounting base 27 are used to reliably fix the first platinum resistance 11, the second platinum resistance 12 and the third platinum resistance 13 on the cylindrical box 1.

[0067] refer to Figure 9 A method for multi-point temperature measurement under rotational conditions, comprising the following steps:

[0068] The temperature measurements T1 of the first platinum resistance thermometer 11, T2 of the second platinum resistance thermometer 12, and T3 of the third platinum resistance thermometer 13 in the temperature compensation subsystem are collected. The average value of T1, T2, and T3 is calculated and denoted as the compensation temperature T. AVE .

[0069] Based on the specific type of thermocouple selected, look up the millivolt value that matches the compensation temperature TAVE in the corresponding calibration table and record it as the reference millivolt value U'.

[0070] The multi-point millivolt values ​​of the thermocouple bundle in the temperature difference measurement subsystem are collected and denoted as the temperature difference millivolt value U.

[0071] Calculate the algebraic sum of the reference millivolt value U' and the temperature difference millivolt value U”, and denote it as the corrected millivolt value U.

[0072] Based on the specific type of thermocouple selected, look up the temperature value that matches the calibration millivolt value U in the corresponding calibration table, and record it as the actual temperature T of the test piece at the point to be measured. REAL .

[0073] Furthermore, the implementation steps for multi-point temperature measurement under rotation using the above system are as follows:

[0074] S1: Connect the compensated temperature measurement subsystem. Specifically: complete the assembly of all components inside the cylindrical housing 1; connect the signal wires from the first platinum resistance thermometer 11, the second platinum resistance thermometer 12, and the third platinum resistance thermometer 13 to the three independent data input channels of the ADAM-4015 resistance temperature detection module 14; connect the two data output channels DATA+ and DATA- of the ADAM-4015 resistance temperature detection module 14 to the third rotor end interface 15 and the fourth rotor end interface 16 of the slip ring 4; connect the data input channels DATA+ and DATA- of the ADAM-4520 signal conversion module 9 to the third stator end interface 17 and the fourth stator end interface 18 of the slip ring 4.

[0075] S2: Connect the temperature difference measurement subsystem. Specifically: Complete the assembly of all components inside the square box 2; take a signal wire bundle, connect one end to the 128 independent differential input channels of the sixteen ADAM-4118 analog input modules 3, and divide the other end into four signal sub-bundles, passing them out of the box from the two integrated box upper lead tubes 37 and the two integrated box lower lead tubes 36 on both sides of the square box 2; merge the four signal sub-bundles after they exit the square box 2 in pairs, and introduce them into the cylindrical box 1 through the junction box upper lead tube 29 and the junction box lower lead tube 28, connecting them to one end of several free terminals; divide the thermocouple bundle led out from the test piece TS to be measured into two thermocouple wire bundles, and connect them through the junction box upper lead tube... 29 and the junction box lower lead pipe 28 are introduced into the cylindrical box 1 and connected to the other end of several free wiring terminals; the data output channels DATA+ and DATA- of the sixteen ADAM-4118 analog input modules 3 are connected in parallel and two signal wires are led out, leading out from the round hole at the front of the square box 2 and connected to the first rotor end interface 5 and the second rotor end interface 6 of the slip ring 4; the data input channels DATA+ and DATA- of the ADAM-4520 signal conversion module 9 are connected to the first stator end interface 7 and the second stator end interface 8 of the slip ring 4; the data output channel RS-232 of the ADAM-4520 signal conversion module 9 is connected to the computer 10.

[0076] S3: Connect the power supply system. Specifically: Lead out the positive and negative terminals of the 24V DC power supply 23 through power supply wires and divide them into two parallel branches. One branch is connected to the fifth stator terminal interface 21 and the sixth stator terminal interface 22 of the slip ring 4, and the other branch is connected to the +Vs and GND channels of the ADAM-4520 signal conversion module 9. The +Vs and GND channels of the sixteen ADAM-4118 analog input modules 3 are connected in parallel and then two power supply wires are led out from the round hole on the front of the square box 2 and connected to the fifth rotor terminal interface 19 and the sixth rotor terminal interface 20 of the slip ring 4.

[0077] S4: Write and execute the control program. Specifically, after the computer 10 issues the start command for data acquisition, the algorithm of the data acquisition program performs the following functions: acquire the temperature measurement value T1 of the first platinum resistance thermometer 11, the temperature measurement value T2 of the second platinum resistance thermometer 12, and the temperature measurement value T3 of the third platinum resistance thermometer 13; determine whether the difference between the maximum and minimum values ​​of T1, T2, and T3 is less than 0.5K. If it is less than 0.5K, it is considered that the internal temperature distribution of the cylindrical box 1 has reached uniformity and the conditions for temperature compensation acquisition are met; otherwise, the acquisition and judgment process needs to be repeated. After the conditions for temperature compensation acquisition are met, output T1, T2, and T3, and calculate the average value of the three temperatures as the compensation temperature, denoted as T. AVE Find the compensation temperature T in the thermocouple calibration table. AVEThe corresponding millivolt value is used as the reference millivolt value, denoted as U'; the temperature difference millivolt value generated by the thermocouple bundle drawn from the test piece is collected, denoted as U”; the algebraic sum of the reference millivolt value U' and the temperature difference millivolt value U” is calculated as the correction millivolt value, denoted as U; the temperature corresponding to the correction millivolt value U is found in the thermocouple calibration table and used as the actual test temperature, denoted as T. REAL After the above steps are completed, the three thermocouple temperature measurement processes will continue to cycle until the computer 10 issues a data acquisition termination command.

[0078] Specifically, the six circuit interface channels at the rotor end and stator end of the slip ring maintain a one-to-one connection relationship, and the specific connection method is shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082]

[0083] Furthermore, the following are examples of practical applications of the multi-point temperature measurement system under rotational conditions proposed in this invention:

[0084] Taking four-point rotational temperature measurement as an example, under experimental conditions of ambient gas supply, Reynolds number Re = 20000, and rotational speed n = 0 to 800 rpm, the temperature measurement results are shown in Table 2. The results indicate that using three platinum resistance thermometers to measure the cold junction temperature at three points and then taking the average as the final compensation temperature can effectively reduce the measurement error of the cold junction compensation temperature and improve the accuracy of thermocouple temperature measurement. The temperature change at the same measurement point under different rotational speeds reflects the influence of rotation on the internal flow and heat transfer of the experimental piece, thus well meeting the experimental requirements.

[0085] Table 2

[0086]

[0087]

[0088] The beneficial effects of this invention are as follows:

[0089] This invention improves the measurement accuracy of cold junction compensation temperature by setting up three platinum resistance thermometers for temperature data acquisition; it introduces free wiring terminals by setting up a thermocouple junction box independent of the rotation axis, thereby improving experimental efficiency; and by setting up two module integration boxes independent of the rotation axis, it expands the total number of ADAM-4118 analog input modules to 32 and the number of temperature measurement points to 256, meeting the requirements for multi-point temperature measurement under rotation conditions.

[0090] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0091] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A multi-point temperature measurement system under rotating conditions, characterized in that, include: Temperature difference measurement subsystem, compensated temperature measurement subsystem, and power supply system; The temperature difference measurement subsystem includes: two module integration boxes, an ADAM-4520 signal conversion module, and a computer; the compensated temperature measurement subsystem includes: two thermocouple junction boxes; the power supply system includes: a 24V DC power supply and a slip ring; the module integration box includes: sixteen ADAM-4118 analog input modules, a square box, two upper lead tubes for the integration box, and two lower lead tubes for the integration box; the thermocouple junction box includes: a first platinum resistance thermometer, a second platinum resistance thermometer, a third platinum resistance thermometer, upper lead tubes for the junction box, lower lead tubes for the junction box, a cylindrical box, an ADAM-4015 resistance temperature detection module, and several free-connection terminals; the slip ring includes: a first rotor end interface, a second rotor end interface, a third rotor end interface, a fourth rotor end interface, a fifth rotor end interface, a sixth rotor end interface, a first stator end interface, a second stator end interface, a third stator end interface, a fourth stator end interface, a fifth stator end interface, and a sixth stator end interface; Two upper and two lower integrated box lead-in pipes are disposed on the left and right sides of the square box; the upper and lower junction box lead-in pipes are disposed on the side of the cylindrical box; the first end of the free terminal is connected to the temperature measuring point on the experimental piece to be measured via a thermocouple bundle through the upper and lower junction box lead-in pipes; the second end of the free terminal is connected to all the aforementioned components via a signal wire bundle evenly divided into four paths through the upper and lower junction box lead-in pipes, the upper and lower integrated box lead-in pipes. The ADAM-4118 analog input module has independent differential input channels; the DATA+ and DATA- terminals of all ADAM-4118 analog input modules are connected in parallel, and two signal wires are led out to connect to the first rotor end interface and the second rotor end interface respectively; the first stator end interface and the second stator end interface are connected to the DATA+ and DATA- terminals of the ADAM-4520 signal conversion module respectively; the RS-232 data output channel of the ADAM-4520 signal conversion module is connected to the computer; The first, second, and third platinum resistance resistors are respectively connected to the three independent data input channels of the ADAM-4015 resistance temperature detection module; the DATA+ and DATA- terminals of the ADAM-4015 resistance temperature detection module are respectively connected to the third rotor end interface and the fourth rotor end interface; the third stator end interface and the fourth stator end interface are respectively connected to the DATA+ and DATA- terminals of the ADAM-4520 signal conversion module; the positive and negative terminals of the 24V DC power supply are connected to the... The fifth stator terminal interface and the sixth stator terminal interface are connected; the +Vs and GND terminals of the ADAM-4015 resistance temperature detection module are connected in parallel with the +Vs and GND terminals of all the ADAM-4118 analog input modules, and two power supply wires are led out to connect to the fifth rotor terminal interface and the sixth rotor terminal interface respectively; the two module integration boxes are symmetrically arranged based on the rotation axis, and the total number of ADAM-4118 analog input modules installed is expanded to 32 and the number of temperature measurement points is expanded to 256 through two module integration boxes independent of the rotation axis; The ADAM-4118 analog input module is used to convert the temperature measurement millivolt analog signal transmitted by the thermocouple bundle into an RS-485 digital signal; the ADAM-4015 resistance temperature detection module is used to convert the resistance temperature signals of the first platinum resistance thermometer, the second platinum resistance thermometer, and the third platinum resistance thermometer into RS-485 digital signals; the slip ring is used to transmit the RS-485 digital signals output by the ADAM-4118 analog input module and the ADAM-4015 resistance temperature detection module to the ADAM-4520 signal conversion module; the ADAM-4520 signal conversion module is used to convert the RS-485 digital signals output by the ADAM-4118 analog input module and the ADAM-4015 resistance temperature detection module into RS-232 signals, and transmit the RS-232 signals to the computer.

2. The multi-point temperature measurement system under rotating conditions according to claim 1, characterized in that, The module integration box also includes: a support partition, a rear cover plate, a square box cover plate, four 4118 lower silicone pads and four 4118 upper silicone pads; The rear cover is located on the rear side of the square box; four 4118 lower silicone pads are attached to the bottom groove of the square box; sixteen ADAM-4118 analog input modules are divided into four groups and fixed on the four 4118 lower silicone pads; four 4118 upper silicone pads are attached to the upper side of the four groups of ADAM-4118 analog input modules; the support partition is fixed on the four 4118 upper silicone pads; and the square box cover is fixed on the upper side of the square box.

3. The multi-point temperature measurement system under rotating conditions according to claim 1, characterized in that, The thermocouple junction box also includes: a heat insulation pad, a first heat insulation mounting base, a second heat insulation mounting base, a third heat insulation mounting base, a 4015 lower silicone pad, a 4015 upper silicone pad, a pressure plate, a pressure pad, and a round box cover. The heat insulation pad is attached to the bottom outer side of the cylindrical box; the 4015 lower silicone pad is attached to the inner bottom groove of the cylindrical box; the ADAM-4015 resistance temperature detection module is fixed on the 4015 lower silicone pad; the 4015 upper silicone pad is attached to the upper side of the ADAM-4015 resistance temperature detection module; the clamping plate is fixed on the 4015 upper silicone pad; the clamping pad is attached to the upper side of the extension column of the clamping plate; the cylindrical box cover is fixed on the clamping pad; the first heat insulation mounting base, the second heat insulation mounting base, and the third heat insulation mounting base are all fixed to the side of the cylindrical box; the first platinum resistance thermometer, the second platinum resistance thermometer, and the third platinum resistance thermometer are respectively fixed... The platinum resistance thermometers are fixed on the first, second, and third heat-insulating mounting bases. From a top-down view, the angle between the first and third platinum resistance thermometers and the center of the cylindrical housing is 180 degrees. From a top-down view, the angle between the first and second platinum resistance thermometers and the center of the cylindrical housing is 120 degrees. From a top-down view, the angle between the second and third platinum resistance thermometers and the center of the cylindrical housing is 60 degrees. The distance from the center of the first platinum resistance thermometer to the bottom of the cylindrical housing is one-quarter of the internal height of the housing. The distance from the center of the second platinum resistance thermometer to the bottom of the cylindrical housing is one-half of the internal height of the housing. The distance from the center of the third platinum resistance thermometer to the bottom of the cylindrical housing is three-quarters of the internal height of the housing.

4. The multi-point temperature measurement system under rotating conditions according to claim 1, characterized in that, The first platinum resistance, the second platinum resistance, and the third platinum resistance are all platinum resistances with Class A precision.

5. A multi-point temperature measurement system under rotating conditions according to claim 1, characterized in that, The free-connecting terminal block has a multi-row plug-in structure.

6. The multi-point temperature measurement system under rotating conditions according to claim 1, characterized in that, The signal wire is a Teflon-plated silver-shielded wire.

7. A multi-point temperature measurement system in a rotating state according to claim 3, characterized in that, The first heat-insulating mounting base, the second heat-insulating mounting base, and the third heat-insulating mounting base are all made of G11 epoxy glass fiber.

8. A multi-point temperature measurement system in a rotating state according to claim 3, characterized in that, The material of the heat insulation pad is polytetrafluoroethylene.

9. A method for multi-point temperature measurement under rotating conditions, characterized in that, The method, applied to the multi-point temperature measurement system in a rotating state as described in claim 1, comprises: The first temperature measurement value of the first platinum resistance, the second temperature measurement value of the second platinum resistance, and the third temperature measurement value of the third platinum resistance are collected, and the average value of the first temperature measurement value, the second temperature measurement value, and the third temperature measurement value is calculated to obtain the compensation temperature. Based on the type of thermocouple used, the reference millivolt value is obtained by looking up the millivolt value that matches the compensation temperature in the preset calibration table. The multi-point millivolt values ​​of the thermocouple bundle are collected to obtain the temperature difference millivolt value; The corrected millivolt value is obtained by calculating the algebraic sum of the reference millivolt value and the temperature difference millivolt value. Based on the type of thermocouple used, the temperature value that matches the calibration millivolt value in the preset calibration table is looked up to obtain the actual temperature of the target test piece temperature measurement point.

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