Multi-point temperature measurement system and method in rotating state

Abstract

The invention belongs to the technical field of temperature measurement, and provides a multi-point temperature measurement system and method in a rotating state, and the system comprises a temperature difference measurement subsystem, a compensation temperature measurement subsystem, and a power supply subsystem. The temperature difference measurement subsystem comprises two module integration boxes, an ADAM-4520 signal conversion module and a computer; the compensation temperature measurement subsystem comprises two thermocouple junction boxes; the power supply subsystem comprises a 24V DC power supply and a slip ring. According to the invention, the three platinum resistors are arranged for temperature data acquisition, so that the measurement precision of the cold junction compensation temperature is improved; by introducing a free wiring terminal, the experiment efficiency is improved; by arranging the two module integration boxes, the total installation number of the ADAM-4118 analog quantity input modules is expanded to 32, the number of temperature measuring points is expanded to 256, and the requirement for measuring the temperature of multiple points under the rotating condition is met.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measurement, and in particular to a multi-point temperature measurement system and method in a rotating state. Background Art

[0002] With the continuous improvement of the performance of modern aircraft engines, the temperature before the turbine has also been rising. In addition, the turbine rotor components work at high speed, which makes the turbine rotor blades face the severe test of high temperature, high pressure and high centrifugal load. The target temperature before the turbine of the latest generation of aircraft engines has exceeded 2000K, which is significantly higher than the upper temperature limit of the new high-temperature alloy oxide dispersion alloy. Therefore, in addition to continuing to develop new heat-resistant metal materials, the use of efficient cooling technology is an inevitable choice to make up for the temperature difference between the two. The efficient cooling design for turbine blades usually adopts a composite cooling solution, that is, a combination of internal cooling and external cooling of the blade. Among them, internal cooling requires a more complex flow channel to be set inside the blade and various forms of cooling strengthening structures, such as spoiler columns, ribs, double walls, etc., and external cooling requires a number of overflow holes to be set on the blade surface. In the actual working process, the cooling air is supplied to the inner cooling channel through the air inlet at the root tenon of the blade, and flows out from the overflow hole on the blade surface and the dust removal hole on the top after cooling the inner wall surface. Among them, the cold air flowing out of the overflow hole on the blade surface forms a protective air film on its surface, which plays a role in isolating the high-temperature combustion gas. In recent years, thermal barrier coating technology has also been applied to thermal protection of turbine blade surfaces, which, together with internal cooling and film cooling, further improves the temperature resistance of blades. Accurately obtaining temperature information is the key to the study of efficient cooling of turbine blades. Thermocouple temperature measurement has high accuracy and reliability and is widely used in experiments. According to the principle of thermocouple temperature measurement, cold end compensation must be performed to obtain the temperature value of the point to be measured. Compensation under static conditions is easier to achieve. During the experiment, the cold end is usually placed in an ice trough filled with an ice-water mixture to keep it at 0°C. The temperature value of the point to be measured can be directly read by querying the graduation table of the corresponding model of thermocouple. However, the thermocouple temperature measurement of rotating test pieces faces the problem of signal transmission between static and dynamic. Limited by the number of lead-in slip ring channels, if the temperature compensation end is placed on the external static side, only a few thermocouple millivolt signals can be derived, and as an analog signal, it is very susceptible to interference during dynamic and static transmission. Therefore, from the perspective of ensuring the quantity and quality of temperature signals, the temperature compensation end is usually rotated together with the test piece, and the thermocouple millivolt signal is first converted into a digital signal, and then the digital signal is transmitted to the digital acquisition system on the stationary side by the lead slip ring. However, the temperature compensation end on the rotating side is no longer suitable for ice trough insulation, and the cold end temperature correction method is often used in practice. The principle of this method is to first measure the cold end temperature as the compensation temperature, query the scale to obtain the corresponding millivolt potential difference, and then add the millivolt potential difference to the millivolt potential difference measured by the thermocouple to obtain the total millivolt potential difference. Finally, query the scale 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 in this method is no longer maintained at 0°C, it will change with the ambient temperature during the experiment, so improving the measurement accuracy of the compensation temperature is an issue that must be considered. In addition, although the thermocouple millivolt signal can be converted into a digital signal through a thermocouple input module that rotates with the test piece, the dynamic and static conversion output is completed by the lead slip ring.However, the rotating centrifugal load at high speed has greatly limited the number of modules and installation positions, restricting the increase in the number of temperature measurement points on the test bench. Some teams have conducted in-depth research on the rotating heat exchange of turbine blades. The temperature compensation device adopts a disc stacking design, and the DS18B20 chip is used for temperature measurement and temperature compensation. However, the temperature measurement accuracy of this type of chip is only ±0.5K. In actual use, the temperature rise caused by the rotation of the bearing will be transmitted along the shaft to the temperature compensation device, and the resulting non-uniform temperature field will further reduce the measurement accuracy of the compensation temperature. Due to space limitations, the connection between the temperature measuring thermocouple bundle and the signal wire is connected at a single point through a pin-shaped terminal, and the wiring takes a long time in the experimental preparation stage. In addition, the disc stacking structure also limits the number of thermocouple input modules that can be installed, and the maximum number of temperature measurement points is only 108. If the thermocouple input module fails and needs to be replaced, this structure will greatly increase the difficulty of disassembling and replacing the module.

[0003] Although the upgrade and renovation of the experimental bench in recent years has increased the maximum temperature measurement points to 192, the temperature compensation device still uses the disc stacking design. The number of thermocouple input modules and measurement points is expanded only by increasing the stacking number and radial size of the module mounting disc. It does not fundamentally solve the problems of limited number of measurement points, small module installation space, and difficult fault replacement. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a multi-point temperature measurement system and method under a rotating state, so as to achieve improved compensation temperature accuracy, expanded wiring space, improved experimental efficiency and increased temperature measurement points.

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

[0006] A multi-point temperature measurement system in a rotating state, comprising: a temperature difference measurement subsystem, a compensation temperature measurement subsystem and a power supply subsystem; the temperature difference measurement subsystem comprises: two module integration boxes, an ADAM-4520 signal conversion module and a computer; the compensation temperature measurement subsystem comprises: two thermocouple junction boxes; the power supply subsystem comprises: a 24V DC power supply and a slip ring; the module integration box comprises: sixteen ADAM-4118 analog input modules, a square box body, two integrated box upper lead tubes and two integrated box lower lead tubes Tube; the thermocouple junction box includes: a first platinum resistor, a second platinum resistor, a third platinum resistor, an upper lead tube of the junction box, a lower lead tube of the junction box, a cylindrical box body, an ADAM-4015 resistance temperature detection module and a plurality of free wiring 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] The two upper lead tubes of the integrated box and the two lower lead tubes of the integrated box are arranged on the left and right sides of the square box; the upper lead tube of the junction box and the lower lead tube of the junction box are arranged on the side of the cylindrical box; the first end of the free wiring terminal is connected to the temperature measuring point on the test piece to be measured by the thermocouple bundle through the upper lead tube of the junction box and the lower lead tube of the junction box; the second end of the free wiring terminal is connected to the independent differential input channels of all the ADAM-4118 analog input modules by the signal wire bundle divided into four paths through the upper lead tube of the junction box, the lower lead tube of the junction box, the upper lead tube of the integrated box and the lower lead tube of the integrated box; the DATA+ end and DATA- end of all the ADAM-4118 analog input modules are connected in parallel with each other, and then two signal wires are led out to be connected 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+ end and DATA- end of the ADAM-4520 signal conversion module respectively; the ADAM-452 0 signal conversion module is connected to the computer; the first platinum resistor, the second platinum resistor and the third platinum resistor are respectively connected to the 3 independent data input channels of the ADAM-4015 resistive temperature detection module; the DATA+ terminal and DATA- terminal of the ADAM-4015 resistive 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+ terminal and DATA- terminal of the ADAM-4520 signal conversion module; the positive and negative electrodes 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 terminal and GND terminal of the ADAM-4015 resistive temperature detection module are connected in parallel with the +Vs terminal and GND terminal of all the ADAM-4118 analog input modules, and then two power supply wires are drawn out to be connected to the fifth rotor end interface and the sixth rotor end interface respectively; the two module integration boxes are symmetrically arranged 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 beam into an RS-485 digital signal; the ADAM-4015 resistive temperature detection module is used to convert the thermal resistance signals of the first platinum resistor, the second platinum resistor and the third platinum resistor into RS-485 digital signals; the slip ring is used to transfer the RS-485 digital signals output by the ADAM-4118 analog input module and the ADAM-4015 resistive 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 resistive temperature detection module into RS-232 signals, and transmit the RS-232 signals to the computer.

[0009] Preferably, the module integrated box further comprises: a supporting 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 arranged on the rear side of the square box; the four 4118 lower silicone pads are attached to the bottom grooves of the square box; the sixteen ADAM-4118 analog input modules are evenly divided into four groups and fixed on the four 4118 lower silicone pads; the four 4118 upper silicone pads are attached to the upper sides of the four groups of ADAM-4118 analog input modules; the supporting 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 comprises: a thermal insulation pad, a first thermal insulation mounting seat, a second thermal insulation mounting seat, a third thermal insulation mounting seat, a 4015 lower silicone pad, a 4015 upper silicone pad, a compression plate, a compression rubber pad and a round box cover;

[0012] The thermal insulation pad is attached to the outer side of the bottom of the cylindrical box; the 4015 lower silicone pad is attached to the inner bottom groove of the cylindrical box; the ADAM-4015 resistive 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 resistive temperature detection module; the compression plate is fixed on the 4015 upper silicone pad; the compression rubber pad is attached to the upper side of the extension column of the compression plate; the round box cover is fixed on the compression rubber pad; the first thermal insulation mounting seat, the second thermal insulation mounting seat and the third thermal insulation mounting seat are all fixed to the side of the cylindrical box; the first platinum resistor, the second platinum resistor and the third platinum resistor are respectively fixed fixed on the first thermal insulation mounting seat, the second thermal insulation mounting seat and the third thermal insulation mounting seat; the central angle between the first platinum resistor, the third platinum resistor and the cylindrical box is 180 degrees when viewed from above; the central angle between the first platinum resistor, the second platinum resistor and the cylindrical box is 120 degrees when viewed from above; the central angle between the second platinum resistor, the third platinum resistor and the cylindrical box is 60 degrees when viewed from above; the distance between the center of the first platinum resistor and the bottom of the cylindrical box is one-fourth of the internal height of the box; the distance between the center of the second platinum resistor and the bottom of the cylindrical box is one-half of the internal height of the box; the distance between the center of the third platinum resistor and the bottom of the cylindrical box is three-quarters of the internal height of the box.

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

[0014] Preferably, the structure of the free wiring terminals is a multi-row plug-in type.

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

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

[0017] Preferably, the thermal insulation pad is made of polytetrafluoroethylene.

[0018] Preferably, a multi-point temperature measurement method in a rotating state comprises:

[0019] Collecting a first temperature measurement value of the first platinum resistor, a second temperature measurement value of the second platinum resistor, and a third temperature measurement value of the third platinum resistor, and calculating an average of the first temperature measurement value, the second temperature measurement value, and the third temperature measurement value to obtain a compensation temperature;

[0020] According to the type of thermocouple used, the millivolt value matching the compensation temperature in the preset graduation table is queried to obtain the reference millivolt value;

[0021] Collecting multi-point millivolt values ​​of the thermocouple bundle to obtain a temperature difference millivolt value;

[0022] Calculating the algebraic sum of the reference millivolt value and the temperature difference millivolt value to obtain a corrected millivolt value;

[0023] According to the type of thermocouple used, the temperature value matching the corrected millivolt value is queried in a preset graduation table to obtain the actual temperature of the target test piece temperature to be measured.

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

[0025] The present invention provides a multi-point temperature measurement system and method in a rotating state. By setting three platinum resistors for temperature data acquisition, the problem of low accuracy of single-point temperature measurement chips in traditional compensated temperature measurement is solved, and real-time high-precision compensation for thermocouple temperature measurement is realized; by setting a thermocouple junction box independent of the rotating axis and introducing free wiring terminals, the problem of long time consumption for single-point wiring using pin-shaped wiring terminals is solved, and experimental efficiency is improved; by two module integration boxes independent of the rotating axis, the total number of installed ADAM-4118 analog input modules is expanded to 32 and the number of temperature measurement points is expanded to 256, which solves the problem that the maximum number of temperature measurement points in the traditional disc stacking structure is only 108, and the expansion of temperature measurement points is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

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

[0028] Figure 2 A structural diagram of a compensation temperature measurement subsystem provided by an embodiment of the present invention;

[0029] Figure 3 A structural diagram of a power supply subsystem provided in an embodiment of the present invention;

[0030] Figure 4 An exploded diagram of a thermocouple junction box of a compensation temperature measurement subsystem provided in an embodiment of the present invention;

[0031] Figure 5An exploded diagram of the temperature difference measurement subsystem module integration box provided by an embodiment of the present invention;

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

[0033] Figure 7 A circumferential position relationship diagram of three platinum resistors installed in a thermocouple junction box of a compensation temperature measurement subsystem provided in an embodiment of the present invention;

[0034] Figure 8 A height position relationship diagram of three platinum resistors installed in a thermocouple junction box of a compensation temperature measurement subsystem provided in an embodiment of the present invention;

[0035] Fig. 9 A flow chart of a data collection and processing algorithm provided by an embodiment of the present invention;

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

[0037] Fig.11 A device diagram of an ADAM-4015 resistive temperature detection module provided in an embodiment of the present invention;

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

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

[0040] Description of reference numerals:

[0041] 1-cylindrical box, 2-square box, 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 resistor, 12-second platinum resistor, 13-third platinum resistor, 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 end interface, 22-sixth stator end interface, 23-24V DC power supply, 24-thermal insulation pad, 25-first thermal insulation mounting seat, 26-second thermal insulation mounting seat, 27-third thermal insulation mounting seat, 28-lower lead tube of junction box, 29-upper lead tube of junction box, 30-4015 lower silicone pad, 31-4015 upper silicone pad, 32-pressure plate, 33-pressure rubber pad, 34-round box cover, 35-rear cover, 36-lower lead tube of integrated box, 37-upper lead tube of integrated box, 38-4118 lower silicone pad, 39-4118 upper silicone pad, 40-support partition, 41-square box cover, TS-test piece to be measured temperature. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] The object of the present invention is to provide a multi-point temperature measurement system and method in a rotating state, so as to improve the compensation temperature accuracy, expand the wiring space, improve the experimental efficiency and increase the temperature measurement points.

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Figure 1 The temperature difference measurement subsystem structure diagram provided by the embodiment of the present invention is as follows: Figure 2 A structural diagram of a compensation temperature measurement subsystem provided in an embodiment of the present invention, Figure 3 A structural diagram of a power supply subsystem provided in an embodiment of the present invention, Figure 4 An exploded diagram of a thermocouple junction box of a compensation temperature measurement subsystem provided in an embodiment of the present invention, Figure 5 The exploded diagram of the temperature difference measurement subsystem module integrated box provided by the embodiment of the present invention is as follows: Figures 1 to 5 As shown, the present invention provides a multi-point temperature measurement system in a rotating state, including: a temperature difference measurement subsystem, a compensation temperature measurement subsystem and a power supply subsystem; the temperature difference measurement subsystem includes: two module integration boxes, an ADAM-4520 signal conversion module 9 and a computer 10; the compensation temperature measurement subsystem includes: two thermocouple junction boxes; the power supply subsystem 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 body 2, two integration box upper lead tubes 37 and two integration box lower lead tubes 36; the thermocouple junction box package The invention comprises: a first platinum resistor 11, a second platinum resistor 12, a third platinum resistor 13, an upper lead tube 29 of a junction box, a lower lead tube 28 of a junction box, a cylindrical box body 1, an ADAM-4015 resistance temperature detection module 14 and a plurality of free wiring terminals; the slip ring 4 comprises: 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 tubes 37 and two integrated box lower lead tubes 36 are arranged on the left and right sides of the square box 2; the junction box upper lead tube 29 and the junction box lower lead tube 28 are arranged on the side of the cylindrical box 1; the first end of the free wiring terminal is connected to the temperature measuring point on the temperature test piece TS to be measured by using a thermocouple bundle through the junction box upper lead tube 29 and the junction box lower lead tube 28; the second end of the free wiring terminal is connected to the temperature test point on the temperature test piece TS to be measured by using a signal wire bundle divided into four paths through the junction box upper lead tube 29, the junction box lower lead tube 28, the integrated box upper lead tube 37 and the The lead tube 36 under the integrated box 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 then two signal wires are led out to be connected 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 resistor 11, the second platinum resistor 12 and the third platinum resistor 13 are respectively connected to the three independent data input channels of ADAM-4015 resistance temperature detection module 14; the DATA+ terminal and the DATA- terminal of ADAM-4015 resistance temperature detection module 14 are respectively connected to the third rotor terminal interface 15 and the fourth rotor terminal interface 16; the third stator terminal interface 17 and the fourth stator terminal interface 18 are respectively connected to the ADAM-4520 signal converter The DATA+ terminal and DATA- terminal of the switching module 9 are connected; the positive and negative electrodes of the 24V DC power supply 23 are connected to the fifth stator terminal interface 21 and the sixth stator terminal interface 22 through power supply wires; the +Vs terminal and GND terminal of the ADAM-4015 resistance temperature detection module 14 are connected in parallel with the +Vs terminal and GND terminal of all ADAM-4118 analog input modules 3, and then two power supply wires are led out to be connected 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 is used to convert the temperature measurement millivolt analog signal transmitted by the thermocouple beam into an RS-485 digital signal; the ADAM-4015 resistive temperature detection module 14 is used to convert the thermal resistance signals of the first platinum resistor 11, the second platinum resistor 12 and the third platinum resistor 13 into RS-485 digital signals; the slip ring 4 is used to transmit the RS-485 digital signals output by the ADAM-4118 analog input module 3 and the ADAM-4015 resistive temperature detection module 14 to the ADAM-4520 signal conversion module 9; the ADAM-4520 signal conversion module 9 is used to convert the RS-485 digital signals output by the ADAM-4118 analog input module 3 and the ADAM-4015 resistive temperature detection module 14 into RS-232 signals, and transmit the RS-232 signals to the computer 10.

[0048] refer to Figure 5 The module integrated box also includes: a supporting partition 40, a rear cover plate 35, a square box cover plate 41, four 4118 lower silicone pads 38 and four 4118 upper silicone pads 39;

[0049] The rear cover 35 is arranged 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 evenly divided into 4 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 supporting partition 40 is fixed on the four 4118 upper silicone pads 39; the square box cover 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 seat 25, a second heat insulation mounting seat 26, a third heat insulation mounting seat 27, a lower silicone pad 30 of 4015, an upper silicone pad 31 of 4015, a pressing plate 32, a pressing rubber pad 33 and a round box cover 34;

[0051] The thermal insulation pad 24 is attached to the outer side of the bottom of the cylindrical box body 1; the lower silicone pad 30 of 4015 is attached to the inner bottom groove of the cylindrical box body 1; the ADAM-4015 resistive 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 resistive temperature detection module 14; the clamping plate 32 is fixed on the upper silicone pad 31 of 4015; the clamping rubber 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 rubber pad 33; the first thermal insulation mounting seat 25, the second thermal insulation mounting seat 26 and the third thermal insulation mounting seat 27 are all fixed on the side of the cylindrical box body 1; the first platinum resistor 11, the second platinum resistor 12 and the third platinum resistor 13 are respectively Fixed on the first thermal insulation mounting seat 25, the second thermal insulation mounting seat 26 and the third thermal insulation mounting seat 27; the central angle between the first platinum resistor 11, the third platinum resistor 13 and the cylindrical box 1 is 180 degrees when viewed from above; the central angle between the first platinum resistor 11, the second platinum resistor 12 and the cylindrical box 1 is 120 degrees when viewed from above; the central angle between the second platinum resistor 12, the third platinum resistor 13 and the cylindrical box 1 is 60 degrees when viewed from above; the distance between the center of the first platinum resistor 11 and the bottom of the cylindrical box 1 is one-fourth of the internal height of the box; the distance between the center of the second platinum resistor 12 and the bottom of the cylindrical box 1 is one-half of the internal height of the box; the distance between the center of the third platinum resistor 13 and the bottom of the cylindrical box 1 is three-quarters of the internal height of the box.

[0052] Preferably, the first platinum resistor 11 , the second platinum resistor 12 and the third platinum resistor 13 are all platinum resistors with Class A accuracy.

[0053] Specifically, the structure of the free wiring terminal is a multi-row plug-in type.

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

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

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

[0057] refer to Fig. 9 , a multi-point temperature measurement method in a rotating state, comprising:

[0058] Collecting a first temperature measurement value of the first platinum resistor 11, a second temperature measurement value of the second platinum resistor 12, and a third temperature measurement value of the third platinum resistor 13, and calculating an average value of the first temperature measurement value, the second temperature measurement value, and the third temperature measurement value to obtain a compensation temperature;

[0059] According to the type of thermocouple used, query the millivolt value that matches the compensation temperature in the preset graduation table to obtain the reference millivolt value;

[0060] Collect multi-point millivolt values ​​of the thermocouple bundle 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 correction millivolt value;

[0062] According to the type of thermocouple used, the temperature value matching the corrected millivolt value is queried in the preset graduation table to obtain the actual temperature of the target test piece temperature to be measured.

[0063] refer to Fig.10 and Fig.11 One end of the thermocouple bundle is connected to the temperature measuring point on the test piece TS to be measured, and the other end is introduced into the cylindrical box 1 through the upper lead tube 29 of the junction box and the lower lead tube 28 of the junction box and connected to one end of a plurality of free wiring terminals; one end of the signal wire bundle is connected to a total of 128 independent differential input channels of sixteen ADAM-4118 analog input modules 3, and the other end is evenly divided into four signal sub-harnesses and led out of the square box 2 from two upper lead tubes 37 of the integrated box and two lower lead tubes 36 of the integrated box; the four signal sub-harnesses led out of the square box 2 are connected to the upper lead tube 2 of the junction box 9 and the lower lead tube 28 of the junction box are introduced into the cylindrical box body 1 and connected to the other end of a plurality of 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 then two signal wires are led out, which are led out from the round hole in the front of the square box body 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 resistor 11, the second platinum resistor 12 and the third platinum resistor 13 are respectively connected to the three independent data input channels of the ADAM-4015 resistance temperature detection module 14.

[0064] refer to Fig.10 , Fig.11 , Fig.12 as well as Fig.13The two upper lead tubes 37 of the integrated box and the two lower lead tubes 36 of the integrated box are used to lead the four-way signal sub-wiring harnesses from the 128 independent differential channels of the sixteen ADAM-4118 analog input modules 3 out of the square box 2; the upper lead tube 29 of the junction box and the lower lead tube 28 of the junction box are used to lead the thermocouple bundles from the temperature test piece TS to be measured and the four-way signal sub-wiring harnesses from the square box 2 into the cylindrical box 1; the cylindrical box 1 is used to install the first platinum resistance 11, the second The second platinum resistor 12, the third platinum resistor 13, the ADAM-4015 resistance temperature detection module 14, and a plurality of free wiring terminals are provided with a placement space; sixteen ADAM-4118 analog input modules 3 are used to convert the temperature measurement millivolt analog signal transmitted by the thermocouple bundle into RS-485 digital signal; the square box 2 is used to install the sixteen ADAM-4118 analog input modules 3; the slip ring 4 is used for the 24V DC power supply 23 and the ADAM-4118 analog The ADAM-4520 signal conversion module 9 is used to convert the RS-485 digital signal into 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 collection; the first platinum resistor 11 is used to measure the temperature of the first point inside the cylindrical box 1; the second platinum resistor 12 is used to measure the temperature of the second point inside the cylindrical box 1; the third platinum resistor 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 collect the thermal resistance signals of the first platinum resistor 11, the second platinum resistor 12, and the third platinum resistor 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 is used to provide stable support for the four groups of ADAM-4118 analog input modules 3 to offset the rotational centrifugal force; the rear cover 35 is used to facilitate the installation of the four groups of ADAM-4118 analog input modules 3 and the subsequent maintenance of the connected signal wires.

[0066] Preferably, the thermal insulation pad 24 is used to isolate the heat conducted from the laboratory bench to the thermocouple junction box; the clamping plate 32 is used to fasten the ADAM-4015 resistive temperature detection module 14 to resist the rotating centrifugal force; the first thermal insulation mounting seat 25, the second thermal insulation mounting seat 26 and the third thermal insulation mounting seat 27 are used to reliably fix the first platinum resistor 11, the second platinum resistor 12 and the third platinum resistor 13 on the cylindrical box body 1.

[0067] refer to Fig. 9 , a multi-point temperature measurement method under a rotating state, comprising the following steps:

[0068] Collect the temperature measurement value T1 of the first platinum resistor 11, the temperature measurement value T2 of the second platinum resistor 12, and the temperature measurement value T3 of the third platinum resistor 13 in the temperature compensation subsystem, calculate the average value of T1, T2, and T3, and record it as the compensation temperature T AVE .

[0069] According to the specific type of thermocouple selected, query the millivolt value that matches the compensation temperature TAVE in the corresponding graduation table and record it as the reference millivolt value U'.

[0070] Collect the multi-point millivolt values ​​of the thermocouple bundle in the temperature difference measurement subsystem and record them 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 record it as the corrected millivolt value U.

[0072] According to the specific type of thermocouple selected, query the temperature value that matches the correction millivolt value U in the corresponding graduation table and record it as the actual temperature T of the test piece temperature point to be measured. REAL .

[0073] Furthermore, the implementation steps of using the above system to perform multi-point temperature measurement in a rotating state are as follows:

[0074] S1: Connect the compensation temperature measurement subsystem. Specifically: complete the assembly of the components inside the cylindrical box 1; connect the signal wires led out of the first platinum resistor 11, the second platinum resistor 12 and the third platinum resistor 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 the components inside the square box 2; take a signal wire harness, one end of which is connected to the 128 independent differential input channels of the sixteen ADAM-4118 analog input modules 3, and the other end is evenly divided into four signal sub-harnesses, which pass through the box from the two upper lead tubes 37 and the two lower lead tubes 36 of the integrated box on both sides of the square box 2; merge the four signal sub-harnesses after passing through the square box 2 in pairs, and introduce them into the cylindrical box 1 through the upper lead tube 29 and the lower lead tube 28 of the junction box, and connect them to one end of several free wiring terminals; divide the thermocouple bundle drawn from the temperature test piece TS into two thermocouple sub-harnesses, which are connected to the upper lead tube 29 and the lower lead tube 28 of the junction box. 29 and the lower lead tube 28 of the junction box are introduced into the cylindrical box body 1 and connected to the other end of a plurality of free wiring terminals; the data output channels DATA+ and DATA- of the sixteen ADAM-4118 analog input modules 3 are connected in parallel to lead out two signal wires, which are led out from the round hole in the front of the square box body 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 subsystem. Specifically, the positive and negative poles of the 24V DC power supply 23 are led out through the power supply wire and divided into two parallel branches, one of which is connected to the fifth stator end interface 21 and the sixth stator end interface 22 of the slip ring 4, and the other 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 in the front of the square box 2 and connected to the fifth rotor end interface 19 and the sixth rotor end interface 20 of the slip ring 4.

[0077] S4: Write and execute the control program. Specifically, after the computer 10 issues the acquisition start instruction, the algorithm of the data acquisition program implements the following functions: collect the temperature measurement value T1 of the first platinum resistor 11, the temperature measurement value T2 of the second platinum resistor 12, and the temperature measurement value T3 of the third platinum resistor 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 temperature distribution inside the cylindrical box 1 has reached uniformity and meets the compensation temperature acquisition conditions. Otherwise, it is necessary to continue to repeat the acquisition and judgment process; after meeting the compensation temperature acquisition conditions, output T1, T2, and T3, and calculate the average value of the three temperatures as the compensation temperature, recorded as T AVE ; Find the compensation temperature T in the thermocouple graduation table AVEThe corresponding millivolt value is used as the reference millivolt value, recorded as U'; the temperature difference millivolt value generated by the thermocouple bundle drawn from the test piece is collected, recorded 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, recorded as U; the temperature corresponding to the correction millivolt value U in the thermocouple graduation table is found as the actual test temperature, recorded as T REAL After the above steps are completed, the process returns to the three thermocouple temperature measurement process and continues to cycle until the computer 10 issues a collection end instruction.

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

[0079] Table 1

[0080]

[0081]

[0082]

[0083] Furthermore, the practical application examples of the multi-point temperature measurement system in a rotating state proposed by the present invention are as follows:

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

[0085] Table 2

[0086]

[0087]

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

[0089] The present invention improves the measurement accuracy of the cold-end compensation temperature by arranging three platinum resistors for temperature data acquisition; introduces free wiring terminals by arranging a thermocouple junction box independent of the rotating shaft, thereby improving the experimental efficiency; and expands the total number of installed ADAM-4118 analog input modules to 32 and the number of temperature measuring points to 256 by arranging two module integration boxes independent of the rotating shaft, thereby meeting the measurement requirements of multi-point temperatures under rotating conditions.

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

[0091] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A multi-point temperature measurement system in a rotating state, characterized in that: include: Temperature difference measurement subsystem, compensation temperature measurement subsystem and power supply subsystem; The temperature difference measurement subsystem includes: two module integration boxes, ADAM-4520 signal conversion module and computer; the compensation temperature measurement subsystem includes: two thermocouple junction boxes; the power supply subsystem includes: 24V DC power supply and slip ring; the module integration box includes: sixteen ADAM-4118 analog input modules, a square box, two integrated box upper lead tubes and two integrated box lower lead tubes; the thermocouple junction box includes: a first platinum resistor, a second platinum resistor, a third platinum resistor, a junction box upper lead tube, a junction box lower lead tube, a cylindrical box, an ADAM-4015 resistance temperature detection module and a plurality of free wiring 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; The two upper lead tubes of the integrated box and the two lower lead tubes of the integrated box are arranged on the left and right sides of the square box; the upper lead tube of the junction box and the lower lead tube of the junction box are arranged on the side of the cylindrical box; the first end of the free wiring terminal is connected to the temperature measuring point on the test piece to be measured by the thermocouple bundle through the upper lead tube of the junction box and the lower lead tube of the junction box; the second end of the free wiring terminal is connected to the independent differential input channels of all the ADAM-4118 analog input modules by the signal wire bundle divided into four paths through the upper lead tube of the junction box, the lower lead tube of the junction box, the upper lead tube of the integrated box and the lower lead tube of the integrated box; the DATA+ end and DATA- end of all the ADAM-4118 analog input modules are connected in parallel with each other, and then two signal wires are led out to be connected 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+ end and DATA- end of the ADAM-4520 signal conversion module respectively; the ADAM-452 0 signal conversion module is connected to the computer; the first platinum resistor, the second platinum resistor and the third platinum resistor are respectively connected to the 3 independent data input channels of the ADAM-4015 resistive temperature detection module; the DATA+ terminal and DATA- terminal of the ADAM-4015 resistive 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+ terminal and DATA- terminal of the ADAM-4520 signal conversion module; the positive and negative electrodes 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 terminal and GND terminal of the ADAM-4015 resistive temperature detection module are connected in parallel with the +Vs terminal and GND terminal of all the ADAM-4118 analog input modules, and then two power supply wires are drawn out to be connected to the fifth rotor end interface and the sixth rotor end interface respectively; the two module integration boxes are symmetrically arranged based on the rotation axis; The ADAM-4118 analog input module is used to convert the temperature measurement millivolt analog signal transmitted by the thermocouple beam into an RS-485 digital signal; the ADAM-4015 resistive temperature detection module is used to convert the thermal resistance signals of the first platinum resistor, the second platinum resistor and the third platinum resistor into RS-485 digital signals; the slip ring is used to transfer the RS-485 digital signals output by the ADAM-4118 analog input module and the ADAM-4015 resistive 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 resistive temperature detection module into RS-232 signals, and transmit the RS-232 signals to the computer.

2. A multi-point temperature measurement system in a rotating state according to claim 1, characterized in that: The module integrated box also includes: a supporting 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 arranged on the rear side of the square box; the four 4118 lower silicone pads are attached to the bottom grooves of the square box; the sixteen ADAM-4118 analog input modules are evenly divided into four groups and fixed on the four 4118 lower silicone pads; the four 4118 upper silicone pads are attached to the upper sides of the four groups of ADAM-4118 analog input modules; the supporting 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 in a rotating state according to claim 1, characterized in that: The thermocouple junction box also includes: a thermal insulation pad, a first thermal insulation mounting seat, a second thermal insulation mounting seat, a third thermal insulation mounting seat, a 4015 lower silicone pad, a 4015 upper silicone pad, a compression plate, a compression rubber pad and a round box cover; The thermal insulation pad is attached to the outer side of the bottom of the cylindrical box; the 4015 lower silicone pad is attached to the inner bottom groove of the cylindrical box; the ADAM-4015 resistive 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 resistive temperature detection module; the compression plate is fixed on the 4015 upper silicone pad; the compression rubber pad is attached to the upper side of the extension column of the compression plate; the round box cover is fixed on the compression rubber pad; the first thermal insulation mounting seat, the second thermal insulation mounting seat and the third thermal insulation mounting seat are all fixed to the side of the cylindrical box; the first platinum resistor, the second platinum resistor and the third platinum resistor are respectively fixed fixed on the first thermal insulation mounting seat, the second thermal insulation mounting seat and the third thermal insulation mounting seat; the central angle between the first platinum resistor, the third platinum resistor and the cylindrical box is 180 degrees when viewed from above; the central angle between the first platinum resistor, the second platinum resistor and the cylindrical box is 120 degrees when viewed from above; the central angle between the second platinum resistor, the third platinum resistor and the cylindrical box is 60 degrees when viewed from above; the distance between the center of the first platinum resistor and the bottom of the cylindrical box is one-fourth of the internal height of the box; the distance between the center of the second platinum resistor and the bottom of the cylindrical box is one-half of the internal height of the box; the distance between the center of the third platinum resistor and the bottom of the cylindrical box is three-quarters of the internal height of the box.

4. The multi-point temperature measurement system in a rotating state according to claim 1, characterized in that: The first platinum resistor, the second platinum resistor and the third platinum resistor are all platinum resistors with Class A precision.

5. The multi-point temperature measurement system in a rotating state according to claim 1, characterized in that: The structure of the free wiring terminal is a multi-row plug-in type.

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

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

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

9. A method for measuring multi-point temperature in a rotating state, characterized in that: The method for the multi-point temperature measurement system in a rotating state applied to claim 1 comprises: Collecting a first temperature measurement value of the first platinum resistor, a second temperature measurement value of the second platinum resistor, and a third temperature measurement value of the third platinum resistor, and calculating an average of the first temperature measurement value, the second temperature measurement value, and the third temperature measurement value to obtain a compensation temperature; According to the type of thermocouple used, the millivolt value matching the compensation temperature in the preset graduation table is queried to obtain the reference millivolt value; Collecting multi-point millivolt values ​​of the thermocouple bundle to obtain a temperature difference millivolt value; Calculating the algebraic sum of the reference millivolt value and the temperature difference millivolt value to obtain a corrected millivolt value; According to the type of thermocouple used, the temperature value matching the corrected millivolt value is queried in a preset graduation table to obtain the actual temperature of the target test piece temperature to be measured.

Images