Fast response temperature sensor based on multiple frequency compensation

Abstract

The fast response temperature sensor based on multiple frequency compensation disclosed in the present invention belongs to the field of temperature measurement. The present invention includes a thick wire thermocouple, a thin wire thermocouple, a supporting wire, an insulating porcelain tube, a shell and a data acquisition and processing system. The present invention uses thermocouples with different wire diameters as sensitive elements to measure the rapidly changing airflow temperature, adopts Fourier transform and inverse Fourier transform, and proposes multiple concentration factors to perform multiple frequency compensation on the measured temperature sequence. The present invention can avoid the shortcomings of slow response of traditional thermocouple measurements and low measurement accuracy of non-contact methods, and can solve the problem that the current thermocouple sensor cannot measure the high-frequency pulsating airflow temperature due to its own thermal inertia limitation. The present invention has the advantages of fast response, high accuracy, and strong practicality. In addition, based on a large number of experimental tests and analyses, the present invention can further improve the response speed and accuracy of temperature compensation through parameter optimization selection, and improve the efficiency and accuracy of airflow temperature measurement.

Description

Technical Field

[0001] The invention relates to a fast response temperature sensor based on multiple frequency compensation, in particular to a sensor suitable for measuring the temperature of high-frequency pulsating airflow, and belongs to the field of temperature measurement. Background Art

[0002] In the development and production tests of aviation turbine engines, pulse detonation engines, armored vehicle engines, etc., airflow temperature is a key test parameter, usually used for engine performance evaluation, status monitoring, etc. In some cases, the airflow temperature will pulsate at high frequencies, and the pulsation frequency can reach thousands of hertz. Traditional temperature sensors such as thermocouples and thermal resistors cannot meet the needs of high-frequency response. The thinnest thermocouples in the industry can only reach a frequency response of tens of hertz, and the thermal resistor has an even lower frequency response due to the influence of the substrate. Non-contact temperature instruments can theoretically achieve a higher frequency response, but the measurement error is large, and it has not yet entered the practical stage, and its response time is also affected by the instrument demodulation algorithm. Summary of the invention

[0003] The main purpose of the present invention is to provide a fast response temperature sensor based on multiple frequency compensation, which can realize the fast measurement and analysis of high-frequency pulsating airflow temperature based on multiple frequency compensation.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] The fast response temperature sensor based on multiple frequency compensation disclosed in the present invention comprises a thick-wire thermocouple, a thin-wire thermocouple, a supporting thermocouple wire, an insulating porcelain tube, a housing and a data acquisition and processing system. The thick-wire thermocouple and the thin-wire thermocouple are respectively connected to the supporting thermocouple wire, the supporting thermocouple wire is inserted into the insulating porcelain tube, the insulating porcelain tube together with the thick-wire thermocouple, the thin-wire thermocouple and the supporting thermocouple wire is inserted into the housing, and the tail of the supporting thermocouple wire is connected to the data acquisition and processing system. Multiple frequency compensation is performed through the data acquisition and processing system, thereby realizing the rapid measurement and analysis of the high-frequency pulsating airflow temperature.

[0006] The ratio of the diameter of the thick-wire thermocouple to the thin-wire thermocouple of the temperature sensor is in the range of 1.5 to 3.5, and the maximum diameter of the thick-wire thermocouple does not exceed The diameter of the supporting wire is The ratio of the maximum span of the supporting wire to the diameter of the thermocouple it supports is in the range of 20 to 30, the axial length of the supporting wire is in the range of 3 mm to 10 mm, and the axial distance between the thick wire thermocouple and the thin wire thermocouple is 1 mm to 2 mm.

[0007] Preferably, the thick-wire thermocouple and the thin-wire thermocouple are connected to the supporting couple wires by welding, respectively. Both the thick-wire thermocouple and the thin-wire thermocouple are parallel-butt-welded without thermal joints.

[0008] The multiple frequency compensation method comprises the following steps:

[0009] Step 1: Based on the actual measurement results of the temperature sensor, the data acquisition and processing system performs the first frequency compensation on the results. The temperature T after compensation g1 use Calculate, where v is the air velocity, m is a constant, T 1 , T 2 are the measured temperature series of the thin-wire thermocouple and the thick-wire thermocouple, respectively, and D 1 , D 2 are the diameters of thin-wire thermocouples and thick-wire thermocouples, respectively.

[0010] Step 2: Based on the actual measurement results of the temperature sensor and the results of the first frequency compensation, the data acquisition and processing system performs a second frequency compensation on the results. The temperature T after compensation is g2 use Calculate, where T g1 is the temperature sequence after the first frequency compensation, f 2 is the double enrichment factor, and its value range is 0.55 to 0.75.

[0011] Step 3: Based on the actual measurement results of the temperature sensor and the results of the second frequency compensation, the data acquisition and processing system performs a third frequency compensation on the results. The temperature T after compensation is g use Calculate, where T g2 is the temperature sequence after the second frequency compensation, f 3 is the triple enrichment factor, and its value range is 0.2 to 0.4.

[0012] Step 4: After three frequency compensations, smoothing filtering with less than 19 points is used to output the measurement and analysis results of the high-frequency pulsating airflow temperature, thereby realizing rapid measurement and analysis of the high-frequency pulsating airflow temperature.

[0013] Beneficial effects:

[0014] 1. To solve the problem in the prior art that thermocouple sensors cannot measure high-frequency pulsating airflow temperature due to their own thermal inertia limitations, the fast-response temperature sensor based on multiple frequency compensation disclosed in the present invention uses thermocouples with different wire diameters as sensitive elements to measure rapidly changing airflow temperature, adopts Fourier transform and inverse Fourier transform, and proposes multiple concentration factors to perform multiple frequency compensations on the measured temperature sequence to obtain a result close to the actual airflow temperature, avoiding the shortcomings of slow response of traditional thermocouple measurements and low measurement accuracy of non-contact methods, and has the advantages of fast response, high accuracy, strong practicality, etc.

[0015] 2. The fast response temperature sensor based on multiple frequency compensation disclosed by the present invention has the following parameters selected based on a large number of experimental tests and analyses: the ratio of the diameter of the thick wire thermocouple to the thin wire thermocouple of the temperature sensor is in the range of 1.5 to 3.5, and the maximum diameter of the thick wire thermocouple does not exceed The diameter of the supporting wire is Within the range, the ratio of the maximum span of the supporting wire to the diameter of the thermocouple it supports is in the range of 20 to 30, the axial length of the supporting wire is in the range of 3mm to 10mm, and the axial distance between the thick-wire thermocouple and the thin-wire thermocouple is 1mm to 2mm; it can further improve the response speed and accuracy of temperature compensation, thereby improving the dynamic and steady-state accuracy of airflow temperature measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic structural diagram of a fast response temperature sensor based on multiple frequency compensation of the present invention.

[0017] Among them: 1 - thick wire thermocouple, 2 - thin wire thermocouple, 3 - supporting thermocouple wire, 4 - insulating porcelain tube, 5 - shell, 6 - data acquisition and processing system. DETAILED DESCRIPTION

[0018] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0019] like Figure 1 As shown, the fast response temperature sensor based on multiple frequency compensation disclosed in this example includes a thick-wire thermocouple 1, a thin-wire thermocouple 2, a supporting thermocouple wire 3, an insulating porcelain tube 4, a housing 5, and a data acquisition and processing system 6.

[0020] The diameter of the thin-wire thermocouple 2 is The diameter of the thick wire thermocouple 1 is The axial length of the supporting wire 3 of the thin-wire thermocouple 2 is 5 mm, and the maximum span is 8 mm. The axial length of the supporting wire 3 of the thick-wire thermocouple 1 is 8 mm, and the maximum span is 12 mm. The axial distance between the thick-wire thermocouple 1 and the thin-wire thermocouple 2 is 1.2 mm. Both the thick-wire thermocouple 1 and the thin-wire thermocouple 2 are parallel-welded without hot joints.

[0021] The thick-wire thermocouple 1 and the thin-wire thermocouple 2 are connected to the supporting thermocouple wire 3 by welding, respectively. The supporting thermocouple wire 3 is inserted into the four-hole alumina insulating porcelain tube 4. The insulating porcelain tube 4, the thick-wire thermocouple 1, the thin-wire thermocouple 2 and the supporting thermocouple wire 3 are inserted into the metal shell 5 together, and the head and tail are sealed with glue. After sealing, the sensor is placed in an oven for drying. Before measurement, the tail of the supporting thermocouple wire 3 is connected to the data acquisition and processing system 6.

[0022] According to the actual measurement results of the temperature sensor, the data acquisition and processing system 6 performs the first frequency compensation on the results, and the temperature T after compensation is g1 use Calculate, where v is the air velocity, m is 0.5, T 1 , T 2 are the measured temperature series of the thin-wire thermocouple and the thick-wire thermocouple, respectively, and D 1 , D 2 are the diameters of thin-wire thermocouples and thick-wire thermocouples, respectively.

[0023] According to the actual measurement results of the temperature sensor and the results of the first frequency compensation, the data acquisition and processing system 6 performs a second frequency compensation on the results. The temperature T after compensation is g2 use Calculate, where T g1 is the temperature sequence after the first frequency compensation, f 2 is the double enrichment factor, and its value is 0.67.

[0024] According to the actual measurement results of the temperature sensor and the results of the second frequency compensation, the data acquisition and processing system 6 performs a third frequency compensation on the results. The temperature T after compensation is g use Calculate, where T g2 is the temperature sequence after the second frequency compensation, f 3 is the triple enrichment factor, and its value is 0.33.

[0025] After three-time frequency compensation, the measured results are processed by 13-point smoothing filter to output the measurement and analysis results of high-frequency pulsating airflow temperature, thus realizing the rapid measurement and analysis of high-frequency pulsating airflow temperature.

[0026] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fast response temperature sensor based on multiple frequency compensation includes a thick-wire thermocouple, a thin-wire thermocouple, a supporting thermocouple wire, an insulating porcelain tube, a housing and a data acquisition and processing system; the thick-wire thermocouple and the thin-wire thermocouple are respectively connected to the supporting thermocouple wire, the supporting thermocouple wire is inserted into the insulating porcelain tube, the insulating porcelain tube together with the thick-wire thermocouple, the thin-wire thermocouple and the supporting thermocouple wire are inserted into the housing, and the tail of the supporting thermocouple wire is connected to the data acquisition and processing system; multiple frequency compensation is performed through the data acquisition and processing system, thereby realizing rapid measurement and analysis of high-frequency pulsating airflow temperature; Features: The ratio of the diameter of the thick-wire thermocouple to the thin-wire thermocouple of the temperature sensor is in the range of 1.5 to 3.5, and the maximum diameter of the thick-wire thermocouple does not exceed The diameter of the supporting wire is The ratio of the maximum span of the supporting wire to the diameter of the thermocouple it supports is within the range of 20 to 30, the axial length of the supporting wire is within the range of 3 mm to 10 mm, and the axial distance between the thick-wire thermocouple and the thin-wire thermocouple is 1 mm to 2 mm; The multiple frequency compensation method comprises the following steps: Step 1: Based on the actual measurement results of the temperature sensor, the data acquisition and processing system performs the first frequency compensation on the results. The compensated temperature T g1 use Calculate, where v is the air velocity, m is a constant, T 1 , T 2 are the measured temperature series of the thin-wire thermocouple and the thick-wire thermocouple, respectively, and D 1 , D 2 are the diameters of thin-wire thermocouple and thick-wire thermocouple, respectively; Step 2: Based on the actual measurement results of the temperature sensor and the results of the first frequency compensation, the data acquisition and processing system performs a second frequency compensation on the results. The temperature T after compensation is g2 use Calculate, where T g1 is the temperature sequence after the first frequency compensation, f 2 It is a double enrichment factor; Step 3: Based on the actual measurement results of the temperature sensor and the results of the second frequency compensation, the data acquisition and processing system performs a third frequency compensation on the results. The temperature T after compensation is g use Calculation, that is, to achieve rapid measurement of high-frequency pulsating airflow temperature; where T g2 is the temperature sequence after the second frequency compensation, f 3 It is a triple concentration factor.

2. The fast response temperature sensor based on multiple frequency compensation as claimed in claim 1, Features: The thick-wire thermocouple and the thin-wire thermocouple are connected to the supporting couple wires by welding respectively. Both the thick-wire thermocouple and the thin-wire thermocouple are parallel-butt-welded without hot joints.

3. The fast response temperature sensor based on multiple frequency compensation as claimed in claim 1, Features: The method further includes step 4, after three frequency compensations, using smoothing filtering processing below 19 points to output the measurement and analysis results of the high-frequency pulsating airflow temperature, that is, to achieve rapid measurement and analysis of the high-frequency pulsating airflow temperature.

4. The fast response temperature sensor based on multiple frequency compensation as claimed in claim 1, Features: m is 0.5; f 2 is the double enrichment factor, ranging from 0.55 to 0.75; f 3 is the triple enrichment factor, and its value range is 0.2 to 0.4.

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