Method for measuring temperature inside high temperature solid based on nonlinear ultrasonic zero frequency signal

Abstract

The application discloses a high-temperature solid internal temperature measurement method based on nonlinear ultrasonic zero-frequency signals and belongs to the technical field of nondestructive measurement. The method comprises the following steps: firstly, ultrasonic waves are excited on one side of a solid structure under different uniform temperature field conditions, and ultrasonic signals are received on the other side; after the signals are processed, the amplitudes of the nonlinear ultrasonic zero-frequency signals under different uniform temperature fields are observed and recorded; then, the correlation between the amplitudes of the nonlinear ultrasonic zero-frequency signals and temperature is determined; after the correlation between the amplitudes of the nonlinear ultrasonic zero-frequency signals and temperature is determined, the temperature inside the solid structure is obtained in subsequent ultrasonic detection by combining the correlation between the amplitudes of the nonlinear ultrasonic zero-frequency signals and temperature. The application is not limited to the type of solid material, can be used for stable measurement under high-temperature or extremely high-temperature environments, has far higher sensitivity than linear ultrasonic parameters and has good real-time performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-destructive measurement, more particularly, to a high-temperature solid internal temperature measurement method based on nonlinear ultrasonic zero-frequency signals. BACKGROUND

[0002] For some high-temperature structures, the internal temperature distribution and changes are very critical, and the temperature may affect the stability and performance of the equipment. For example, on the turbine blades of an aero-engine, different distributions of temperature can cause thermal stress, leading to fatigue or crack generation. Monitoring the internal changes of the structure helps to analyze the temperature gradient, thereby optimizing the design and avoiding structural problems. The advantage of ultrasonic measurement of the internal temperature of high-temperature structures lies in its non-contact, high-temperature resistance, real-time monitoring capability, and adaptability to complex environments. This makes it an important measurement means in some extreme temperature environments, especially when traditional contact-type temperature measurement techniques are limited, ultrasonic waves can provide an efficient and reliable solution. SUMMARY

[0003] The present application aims to overcome the shortcomings of the prior art and provide a high-temperature solid internal temperature measurement method based on nonlinear ultrasonic zero-frequency signals, which is not limited to the type of solid material and can stably measure in high-temperature or extremely high-temperature environments, with much higher sensitivity than linear ultrasonic parameters and good real-time performance.

[0004] The purpose of the present application is achieved by the following scheme:

[0005] A high-temperature solid internal temperature measurement method based on nonlinear ultrasonic zero-frequency signals, comprising the following steps:

[0006] First, the solid material is excited by ultrasonic waves on one side of the solid structure under different uniform temperature field conditions, and the ultrasonic wave signals are received on the other side. After processing the signals, the amplitude of the nonlinear ultrasonic zero-frequency signals under different uniform temperature fields is observed and recorded;

[0007] Then, the relationship between the amplitude of the nonlinear ultrasonic zero-frequency signals and the temperature is determined;

[0008] After determining the relationship between the amplitude of the nonlinear ultrasonic zero-frequency signals and the temperature, the temperature inside the solid structure is obtained in subsequent ultrasonic detection by combining the relationship between the amplitude of the nonlinear ultrasonic zero-frequency signals and the temperature.

[0009] Further, the signal processing specifically includes modulation and demodulation and filtering processing.

[0010] Further, the relationship between the amplitude of the nonlinear ultrasonic zero-frequency signals and the temperature specifically includes a linear or polynomial relationship.

[0011] Further, the solid material includes a steel material.

[0012] Further, when the solid material is a steel material, the linear correlation relationship is as follows:

[0013] R 线性 = (-2.3 x 10 -8 ) T + 5.5 x 10 -4 (1);

[0014] wherein, R 线性 represents the amplitude when the amplitude of the zero-frequency signal and the temperature are in a linear relationship, and subsequently, when the internal temperature of the steel structure is measured, the amplitude is measured according to the experiment R 线性 and the internal temperature of the structure is calculated according to formula (1) T .

[0015] Further, when the solid material includes a steel material, the polynomial correlation relationship R 多项式 is as follows:

[0016] R 多项式 = (6.7 x 10 -12 ) T 2 - (3.0 x 10 -8 ) T + 5.5 x 10 -4 (2);

[0017] wherein, R 多项式 represents the amplitude when the amplitude of the zero-frequency signal and the temperature are in a polynomial relationship, and subsequently, when the internal temperature of the steel structure is measured, the amplitude is measured according to the experiment R 多项式 and the internal temperature of the structure is calculated according to formula (2) T .

[0018] The beneficial effects of the present application include:

[0019] The present application is not limited to the type of solid material and is suitable for internal temperature measurement of solid high-temperature structures such as pure metals, high-temperature alloys, metal matrix composites, and other non-metallic composites.

[0020] Different from the traditional contact temperature measurement mode using thermocouple and the non-contact temperature measurement mode using infrared imaging, the method for measuring internal temperature of a structure based on nonlinear ultrasonic zero-frequency signal of the application is not limited to the type of solid material, and is applicable to pure metal, high-temperature alloy, metal matrix composite material and other non-metallic composite materials, etc. Moreover, the method is not dependent on the radiation emitted by the measured material, can stably measure in a high-temperature or extremely high-temperature environment, has a much higher sensitivity than linear ultrasonic parameters (such as sound velocity, attenuation, etc.), and has good real-time performance. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 is an ultrasonic detection schematic diagram;

[0023] Figure 2 is a flow chart of the method of the embodiment of the application;

[0024] Figure 3 is an experimental schematic diagram;

[0025] Figure 4 is a zero-frequency signal information diagram in steel material under different internal temperatures;

[0026] Figure 5 is a graph of the relationship between the zero-frequency signal amplitude and the temperature in the steel material. DETAILED DESCRIPTION

[0027] All features disclosed in the embodiments of the present specification, or all steps in the methods or processes impliedly disclosed, can be combined and / or extended, replaced, unless the features and / or steps are mutually exclusive.

[0028] The specific implementation process of the present application is as follows:

[0029] In view of the problems in the background, the present application aims at the measurement requirement of the internal temperature of a high-temperature structure during the operation of a mechanical device, and proposes a method for monitoring the internal temperature of a solid structure based on nonlinear ultrasonic zero-frequency signal, which can realize real-time measurement of the internal temperature of a high-temperature structure in the state of normal operation and stop of a machine device. The method of the present application is applicable to pure metal, high-temperature alloy, metal matrix composite material and other non-metallic composite materials, etc.

[0030] In the present inventive concept, a significant advantage of measuring the temperature inside a structure based on the nonlinear ultrasonic zero-frequency signal is that the amplitude of the zero-frequency signal is directly proportional to the nonlinear parameter of the material. Therefore, even a slight change in temperature causes a change in the microscopic nonlinearity of the material, which can be captured by the high sensitivity of the amplitude change of the zero-frequency signal. This sensitivity is much higher than that of linear ultrasonic parameters (such as sound speed, attenuation). The zero-frequency signal is located in the direct current or very low frequency region of the frequency spectrum, and environmental noise (such as mechanical vibration, electromagnetic interference) is mainly concentrated in the higher frequency band. By designing a suitable band-pass filter or using a phase-locked amplifier, etc., high-frequency environmental noise can be effectively filtered out, greatly improving the signal-to-noise ratio and obtaining more stable and reliable temperature information.

[0031] The method of measuring the temperature inside a structure based on the nonlinear ultrasonic zero-frequency signal is not limited to the type of solid material and is suitable for measuring the internal temperature of solid high-temperature structures such as pure metals, high-temperature alloys, metal matrix composites, and other non-metallic composites.

[0032] The nonlinear ultrasonic zero-frequency signal is a static or quasi-static displacement / stress component with a frequency of zero generated by the inherent nonlinear effect of the material (especially when two waves with similar frequencies interact) under the action of high-amplitude ultrasonic waves. It is a strong indicator of the microscopic nonlinear behavior of the material and is extremely sensitive to early and microscopic damage. It has unique advantages and broad application prospects in the field of non-destructive testing, especially in evaluating fatigue, micro-cracks, and weak adhesion. We found that changes in temperature also cause changes in the amplitude of the nonlinear ultrasonic zero-frequency signal and exhibit certain regularities. Based on this, in a preferred embodiment, the present invention provides a method for measuring the internal temperature of a high-temperature solid based on the nonlinear ultrasonic zero-frequency signal, which specifically includes the following steps:

[0033] As shown in Figure 1 , first, ultrasonic waves are excited on one side of the solid structure and ultrasonic signals are received on the other side under different uniform temperature field conditions. After modulation, demodulation, and filtering, etc., the amplitude of the nonlinear ultrasonic zero-frequency signal under different uniform temperature fields is observed and recorded.

[0034] Next, the correlation between the amplitude of the nonlinear ultrasonic zero-frequency signal and the temperature is determined: the correlation can generally be represented by a linear or polynomial equation. The relationship between the amplitude of the nonlinear ultrasonic zero-frequency signal and the temperature varies for different materials, so the correlation between the amplitude of the nonlinear ultrasonic zero-frequency signal and the temperature needs to be determined specifically for the specific material.

[0035] After determining the correlation between the amplitude of the nonlinear ultrasonic zero-frequency signal and the temperature, the temperature inside the solid structure can be obtained in subsequent ultrasonic detection by combining the correlation between the amplitude of the nonlinear ultrasonic zero-frequency signal and the temperature.

[0036] Specifically, the flowchart of the above-mentioned embodiment method is as shown in Figure 2

[0037] In other embodiments, based on the above-mentioned embodiment method, as shown in Figure 3 , through electromagnetic ultrasonic detection experiments, ultrasonic waves are excited above the steel material, the zero-frequency signal amplitude of the 10mm-thick steel material under different uniform temperature fields is collected (as shown in Figure 4 ), and finally the correlation between the zero-frequency signal amplitude and the temperature in the steel material is obtained, as shown in Table 1 and Figure 5 .

[0038] Table 1: Zero-frequency signal amplitude-temperature correlation data table

[0039]

[0040] The calibration relationship is as follows:

[0041] R 线性 = (-2.3 x 10 -8 ) T + 5.5 x 10 -4 (1);

[0042] R 多项式 = (6.7 x 10 -12 ) T 2 - (3.0 x 10 -8 ) T + 5.5 x 10 -4 (2);

[0043] Among them, R represents the amplitude of the zero-frequency signal. In subsequent steel structure internal temperature measurement, the zero-frequency signal amplitude R can be measured according to the experiment, and the internal temperature of the structure T can be calculated according to the above formula.

[0044] The units described in the embodiments of the present application can be implemented in software or hardware, and the described units can also be set in a processor. In some cases, the names of these units do not constitute a limitation on the units themselves.

[0045] ​According to an aspect of an embodiment of the present application, there is provided a computer program product or computer program, comprising computer instructions stored in a computer readable storage medium. A processor of a computer device reads the computer instructions from the computer readable storage medium, and the processor executes the computer instructions to cause the computer device to perform the method provided in various optional implementation manners described above.

[0046] As another aspect, the embodiment of the present application further provides a computer readable medium, which can be included in the electronic device described in the above embodiments, or can exist independently without being assembled into the electronic device. The computer readable medium carries one or more programs, which, when executed by the electronic device, cause the electronic device to implement the method described in the above embodiments.

Claims

1. A method for measuring the internal temperature of a high-temperature solid based on a nonlinear ultrasonic zero-frequency signal, characterized in that, Includes the following steps: First, under different uniform temperature field conditions, ultrasonic waves are excited on one side of the solid structure and ultrasonic signals are received on the other side. After the signals are processed, the amplitude of the nonlinear ultrasonic zero-frequency signal under different uniform temperature fields is observed and recorded. Next, the correlation between the amplitude of the nonlinear ultrasonic zero-frequency signal and temperature was determined; Once the correlation between the amplitude of the nonlinear ultrasonic zero-frequency signal and temperature is determined, the internal temperature of the solid structure can be obtained in subsequent ultrasonic detection by combining the correlation between the amplitude of the nonlinear ultrasonic zero-frequency signal and temperature. The correlation between the amplitude of the nonlinear ultrasonic zero-frequency signal and temperature specifically includes a linear or polynomial correlation; the solid material includes steel; when the solid material is steel, the calibration formula for the linear correlation is as follows: R 线性 =（-2.3×10 -8 ） T + 5.5×10 -4 （1）； in, R 线性 This represents the amplitude of the zero-frequency signal when the relationship between amplitude and temperature is linear. Subsequent temperature measurements inside the steel structure will be based on experimental measurements. R 线性 The internal temperature of the structure is calculated using equation (1). T ; When the solid material includes steel, the polynomial correlation is... R 多项式 as follows: R 多项式 =（6.7×10 -12 ） T 2 －（3.0×10 -8 ） T + 5.5×10 -4 （2）； in, R 多项式 This represents the amplitude of the zero-frequency signal when the relationship between the amplitude and temperature is polynomial. Subsequent temperature measurements inside the steel structure will be based on experimental measurements. R 多项式 The internal temperature of the structure was calculated using equation (2). T .

2. The method for measuring the internal temperature of a high-temperature solid based on a nonlinear ultrasonic zero-frequency signal according to claim 1, characterized in that, The signal is processed specifically through modulation, demodulation, and filtering.

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