阅读说明：本技术 一种磁热效应高通量表征系统及表征方法 (System and method for representing high flux of magnetocaloric effect ) 是由 刘剑 欧阳亦 王坤 张明晓 于 2020-06-22 设计创作，主要内容包括：本发明提供了一种磁热效应高通量表征系统及表征方法。该系统包括用于放置若干磁性材料样品的样品容纳装置,双层环形海尔贝克磁铁阵列,红外测温装置和控制装置；样品容纳装置设置在双层环形海尔贝克磁铁阵列的环形中心,通过控制环形海尔贝克磁铁阵列的相对旋转控制磁场大小,环形中心区域具有均匀强度的磁场。该系统具有非接触式、可靠、高效的优点,可同时测量多个磁性样品的绝热温度以及其循环稳定性,具有良好的应用前景。(The invention provides a magnetocaloric effect high-flux characterization system and a characterization method. The system comprises a sample accommodating device for accommodating a plurality of magnetic material samples, a double-layer annular Halbach magnet array, an infrared temperature measuring device and a control device; the sample containing device is arranged in the annular center of the double-layer annular Halbach magnet array, the size of the magnetic field is controlled by controlling the relative rotation of the annular Halbach magnet array, and the annular center area has a magnetic field with uniform strength. The system has the advantages of non-contact, reliability and high efficiency, can simultaneously measure the adiabatic temperature and the cycle stability of a plurality of magnetic samples, and has good application prospect.)

1. A magnetocaloric effect high-flux characterization system is characterized in that: the device comprises a sample accommodating device, a double-layer annular Halbach magnet array, an infrared temperature measuring device and a control device;

the double-layer annular Halbach magnet array consists of two layers, namely an inner layer annular Halbach magnet array and an outer layer annular Halbach magnet array, wherein the outer layer annular Halbach magnet array is coaxially sleeved on the periphery of the inner layer annular Halbach magnet array, and under the action of a driving device, one layer of annular Halbach magnet array can rotate relative to the other layer of annular Halbach magnet array, and the rotating speed is called as the relative rotating speed of the annular Halbach magnet array;

the sample containing device is used for placing a plurality of magnetic material samples;

the sample accommodating device is arranged in the annular center of the double-layer annular Halbach magnet array, the size of the magnetic field is controlled by controlling the rotation, and the annular center area is provided with a uniform magnetic field;

the infrared temperature measuring device is used for measuring the temperature of the magnetic sample in a non-contact manner;

the control device is used for controlling the magnetic field.

2. The magnetocaloric effect high throughput characterization system according to claim 1, characterized by: the sample containment device may contain more than two samples, preferably more than ten samples, more preferably more than fifty samples.

3. The magnetocaloric effect high throughput characterization system according to claim 1, characterized by: the sample holding device is of a slot structure or a laminated structure.

4. The magnetocaloric effect high throughput characterization system according to claim 1, characterized by: the sample containment device is constructed of a low thermal conductivity material;

preferably, the low thermal conductive material is low thermal conductive resin, ceramic or plastic.

5. The magnetocaloric effect high throughput characterization system according to claim 1, characterized by: under the action of the driving device, one layer of the annular Halbach magnet arrays rotates, and the other layer of the annular Halbach magnet arrays is static;

or, under the action of the driving device, one layer of the annular Halbach magnet arrays rotates at a first rotating speed, the other layer of the annular Halbach magnet arrays rotates at a second rotating speed, and the first rotating speed is different from the second rotating speed.

6. The magnetocaloric effect high throughput characterization system according to claim 1, characterized by: the driving device comprises one or more of a motor, compressed gas and a transmission belt.

7. The magnetocaloric effect high throughput characterization system according to claim 1, characterized by: controlling the change rate of the magnetic field by controlling the relative rotation speed of the annular Halbach magnet array;

preferably, the control device controls the relative rotation speed of the annular halbach magnet array by controlling the magnitude of the driving force of the driving device.

8. The magnetocaloric effect high throughput characterization system according to claim 1, characterized by: the control device sets a control program to repeatedly load the magnetic field, so that the cycling stability of the sample magnetocaloric effect is measured.

9. The method for characterizing a magnetocaloric effect high flux characterization system according to any one of claims 1 to 8, characterized by: the method comprises the following steps:

(1) placing a plurality of magnetic samples in a sample containment device;

(2) the driving force of the driving device is regulated and controlled through the control device, so that the relative rotating speed of the annular Halbach magnet array is controlled, the magnetic field in the center of the ring is changed, the infrared temperature measuring device records the temperature of a sample in the process, and the temperature difference before and after the change is the adiabatic temperature change in the magnetic field change process.

10. The method for characterizing a magnetocaloric effect high flux characterization system according to claim 9, characterized by: the method comprises the following steps (3):

(3) and (3) automatically repeating the steps (1) and (2) for a plurality of times through program setting in the control device, and measuring the cycle stability of the magnetocaloric effect of a plurality of samples.

Technical Field

The invention belongs to the technical field of magnetic materials, and particularly relates to a system and a method for representing a high flux of a magnetocaloric effect.

Background

With the social development and the improvement of living standard, the refrigeration technology plays an important role in national production and daily life of people. The traditional refrigeration technology based on gas compression still has the defects of low efficiency, large working noise, large volume and the like at present. After the montreal protocol and the kyoto protocol are signed, the magnetic refrigeration, a novel efficient and environment-friendly solid-state refrigeration technology, is gaining wide attention all over the world. The magnetic refrigeration technology is to use magnetic material as solid refrigerant and to utilize the temperature change of magnetic working medium in the adiabatic magnetizing and demagnetizing processes to refrigerate.

The magnetocaloric effect is mainly characterized by two key parameters of isothermal entropy change and adiabatic temperature change, wherein the adiabatic temperature change is directly related to the refrigerating capacity and the refrigerating temperature range of the refrigerator and is one of the most important parameters for evaluating the magnetic refrigerating performance. The adiabatic temperature change can be obtained by indirect measurement or direct measurement. Indirect measurement is the calculation of adiabatic temperature change by measuring the change in specific heat capacity during the loading of a magnetic field, which is long in measurement period and may cause unavoidable calculation errors. The direct measurement is a contact measurement method, which mainly utilizes a temperature sensing element connected to a sample to measure the adiabatic temperature change, but the magnetic material usually causes the loosening and heat leakage of the sensing element along with the volume change in the phase change process; in addition, factors such as signal conversion lag, poor spatial resolution, and single sample measurement limit the application of the contact measurement method in sample characterization.

The magnetic material system with the magnetocaloric effect is large in number, and when a material with excellent magnetocaloric effect needs to be screened from a large number of magnetic materials, the traditional testing method is poor in reliability and low in efficiency, and is not beneficial to new material development. Furthermore, for practical applications of magnetic materials, the cycling stability of the magnetocaloric effect is as important as the magnetocaloric effect itself. Regarding the cycle stability, the traditional determination method is long in time consumption and incapable of multi-sample characterization, and an efficient and feasible non-contact characterization means is lacked at present to directly determine the adiabatic temperature change in the multi-sample cycle process. Therefore, high-flux magnetocaloric effect characterization and efficient magnetocaloric effect cycle stability test are one of the technical problems that those skilled in the art have overcome.

Disclosure of Invention

In view of the above technical situation, the present invention aims to provide a reliable and efficient magnetocaloric effect high-flux characterization system.

In order to achieve the technical purpose, the invention adopts the technical scheme that:

a magneto-caloric effect high-flux characterization system comprises a sample accommodating device, a double-layer annular Halbach magnet array, an infrared temperature measuring device and a control device;

the double-layer annular Halbach magnet array consists of two layers, namely an inner layer annular Halbach magnet array and an outer layer annular Halbach magnet array, wherein the outer layer annular Halbach magnet array is coaxially sleeved on the periphery of the inner layer annular Halbach magnet array, and under the action of a driving device, one layer of annular Halbach magnet array can rotate relative to the other layer of annular Halbach magnet array, and the rotating speed is called as the relative rotating speed of the annular Halbach magnet array;

the sample containing device is used for placing a plurality of magnetic material samples;

the sample accommodating device is arranged in the annular center of the double-layer annular Halbach magnet array, the size of the magnetic field is controlled by controlling the rotation, and the annular center area is provided with a uniform magnetic field;

the infrared temperature measuring device is used for measuring the temperature of the magnetic sample in a non-contact manner;

the control device is used for controlling the magnetic field.

The driving device is not limited and may be a motor, compressed gas, a transmission belt, etc.

The sample holding device can hold any number of samples, preferably two or more samples, more preferably ten or more samples, and even more preferably fifty or more samples.

The sample holding device is not limited in structure and can be a slot structure, a laminated structure and the like.

The material of the sample holding device is not limited, and preferably low heat conduction materials, such as low heat conduction resin, ceramic, plastic and the like, are used for reducing heat loss of the sample and improving the test accuracy.

As one implementation, one of the layers of annular halbach magnet arrays rotates under the action of the driving device, and the other layer of annular halbach magnet arrays is static.

As another implementation, under the action of the driving device, one of the layers of annular halbach magnet arrays rotates at a first rotation speed, and the other layer of annular halbach magnet arrays rotates at a second rotation speed, wherein the first rotation speed is different from the second rotation speed.

As one implementation, the rate of change of the magnetic field is controlled by controlling the relative rotational speed of the annular halbach magnet array.

In one implementation, the control device controls the relative rotation speed of the annular halbach magnet array by controlling the magnitude of the driving force of the driving device, so as to control the change rate of the magnetic field.

The control device can set a control program to repeatedly load the magnetic field, so that the cycling stability of the multi-sample magnetocaloric effect is measured.

The method for performing the magnetocaloric effect table-pointing on the magnetic sample by using the characterization system of the invention comprises the following steps:

(1) placing a plurality of magnetic samples in a sample containment device;

(2) the driving force of the driving device is regulated and controlled through the control device, so that the relative rotating speed of the annular Halbach magnet array is controlled, the magnetic field in the center of the ring is changed, the infrared temperature measuring device records the temperature of a sample in the process, and the temperature difference before and after the change is the adiabatic temperature change in the magnetic field change process.

Preferably, the method further comprises the following step (3):

(3) and (3) automatically repeating the steps (1) and (2) for a plurality of times through program setting in the control device, and measuring the cycle stability of the magnetocaloric effect of a plurality of samples.

Compared with the prior art, the magnetocaloric effect characterization system provided by the invention has the following beneficial effects:

(1) the double-layer annular Halbach magnet arrays are used, one layer of the annular Halbach magnet arrays can rotate relative to the other layer of the annular Halbach magnet arrays through the driving device, and different magnetic field directions and different magnetic field sizes are realized by adjusting the rotating speed through the control device;

(2) the sample containing device can contain a plurality of samples, and a magnetic field and a measured temperature can be simultaneously loaded on the plurality of magnetic samples in one measurement, so that the magnetocaloric effect of the plurality of samples can be simultaneously represented, and high-flux representation is realized;

(3) the infrared temperature measuring device is used for realizing non-contact measurement of the magnetic sample, and has high reliability, high spatial resolution and high response frequency;

(4) the magnetic field can be repeatedly loaded through the programming of the control device, so that the cycling stability of the multi-sample magnetocaloric effect can be measured.

Therefore, the magnetocaloric effect characterization system has the advantages of non-contact, reliability and high efficiency, can measure the adiabatic temperature and the cycle stability of a magnetic sample, and has good application prospect.

Drawings

FIG. 1 is a schematic structural diagram of a magnetocaloric effect high flux characterization system in example 1 of the present invention.

FIG. 2 is an infrared thermometry image of five samples in one magnetic field cycle in example 1 of the present invention.

FIG. 3 is adiabatic temperature change data measured in one magnetic field cycle for five samples in example 1 of the present invention.

FIG. 4 shows adiabatic temperature changes with cycle number for sample No. 1 in inventive example 1 over one hundred thousand cycles of the magnetic field.

The reference numerals in fig. 1 are: the device comprises an infrared temperature measuring device 1, a double-layer annular Halbach magnet array 2, a sample containing device 3 and a control device 4.

Detailed Description

The present invention will be described in further detail with reference to the embodiments shown in the drawings, wherein the embodiments are intended to facilitate the understanding of the present invention without limiting the scope of the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be construed as being included in the scope of the present invention.

Example 1:

as shown in FIG. 1, the magnetocaloric effect high-flux characterization system comprises an infrared temperature measuring device 1, a double-layer annular Halbach magnet array 2, a sample containing device 3 and a control device 4.

The sample accommodating device is made of PVC plastic and is of a cylindrical slot structure, slots of the sample accommodating device are radial and are composed of four layers, and from the radial center to the outside, each layer can accommodate 1, 8, 15 and 24 samples in sequence.

The double-layer annular Halbach magnet array consists of two layers, namely an inner layer annular Halbach magnet array and an outer layer annular Halbach magnet array, wherein the outer layer annular Halbach magnet array is coaxially sleeved on the periphery of the inner layer annular Halbach magnet array, the outer layer annular Halbach magnet array is static, and the inner layer annular Halbach magnet array can rotate under the action of the motor driving device, so that the size of a magnetic field can be changed. The rotating speed can be controlled by controlling the motor, so that the change rate of the magnetic field can be regulated and controlled. The sample holding device is placed in the center of the ring of the double-layered annular halbach magnet array, and the central region of the ring has a magnetic field of uniform intensity when the magnetic field is applied by the inner annular halbach magnet array.

The infrared temperature measuring device is used for measuring the temperature of the magnetic sample in a non-contact mode.

The control device is a computer, the rotating speed of the motor can be set to realize magnetic field regulation, and a control program is set to repeatedly load a magnetic field, so that the cycling stability of the multi-sample magnetocaloric effect is measured.

Five magnetic material powders La with different components are measured by utilizing the magnetocaloric effect high-flux characterization system_0.7Ce_0.3Fe_11.6-xMn_xSi_1.4H(0<x<0.6), the five samples are respectively numbered as No. 1, No. 2, No. 3, No. 4 and No. 5, and the specific measurement is as follows:

(1) placing the five powder samples with different components into five positions in a slot of a sample accommodating device respectively, and placing the slot in the annular center of a double-layer annular Halbach magnet array;

(2) the rotating speed of the motor is set to be increased from 0Hz to 1Hz and then reduced to 0Hz through a program in a computer, the inner layer annular Halbach magnet array rotates relative to the outer layer annular Halbach magnet array, the size of a magnetic field applied to five powder samples with different components is increased from 0T to 1.3T and then reduced to 0T;

in the process, the infrared temperature measuring probe is aligned with the sample, the focal length is adjusted, the position of the sample is identified, non-contact measurement is carried out, and infrared temperature measuring images of five samples in the magnetic field loading and unloading process are obtained, as shown in fig. 2, different brightness of the sample represents different surface temperatures of the sample;

(3) setting and automatically repeating the steps (1) and (2) ten thousand times through a program, and measuring the cycling stability of the multi-sample magnetocaloric effect;

(4) and (3) turning off a power supply of the test system, analyzing data through a computer system to obtain the adiabatic temperature change of the sample in single and multiple cycles, and analyzing the adiabatic temperature change size and the cycle stability of the samples with different components.

Fig. 3 and 4 are adiabatic temperature change data measured for sample No. 1 in one magnetic field cycle, and adiabatic temperature change in one hundred thousand magnetic field cycles as a function of the number of cycles, respectively.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.