阅读说明：本技术 一种管道保温材料性能的检测装置及评价方法 (Detection device and evaluation method for performance of pipeline heat-insulating material ) 是由 贾振 何嵩 杨东 刘柏寒 赵乐岩 闫东阳 李丛康 孙守斌 周波 陈振一 于 2021-09-15 设计创作，主要内容包括：一种管道保温材料性能的检测装置及评价方法,包括保温性能检测管道和检测仪表；安装在生产运行的能源介质输送管道或相关能源介质实验发生装置的输送管道上的疏水门出口处；检测仪表包括安装在保温性能检测管道与疏水门之间的流量孔板、温度补偿电偶和压力变送器；还包括检测管道的入口压力检测变送器、入口温度检测传感器、出口压力检测变送器和出口温度检测传感器；还包括保温材料内表面测温传感器和保温材料外表面测温传感器；通过检测仪表的检测值计算保温材料的热损失。为改进管道保温材料性能检测方法,验证保温材料经济厚度的使用效果,提供行之有效的手段。为新型能源介质输送管道保温材料的推广应用搭建确实可行的检验平台。(A detection device and evaluation method of the pipeline heat insulation material performance, including heat insulation performance detection pipeline and instrumentation; the drainage door is arranged at the outlet of a drainage door on a production and operation energy medium conveying pipeline or a conveying pipeline of a related energy medium experiment generating device; the detection instrument comprises a flow orifice plate, a temperature compensation couple and a pressure transmitter which are arranged between the heat insulation performance detection pipeline and the drainage door; the device also comprises an inlet pressure detection transmitter, an inlet temperature detection sensor, an outlet pressure detection transmitter and an outlet temperature detection sensor which are used for detecting the pipeline; the temperature sensor on the inner surface of the heat-insulating material and the temperature sensor on the outer surface of the heat-insulating material are also included; and calculating the heat loss of the heat-insulating material through the detection value of the detection instrument. The method provides an effective means for improving the performance detection method of the pipeline heat-insulating material and verifying the use effect of the economic thickness of the heat-insulating material. A feasible inspection platform is established for popularization and application of the novel energy medium conveying pipeline heat-insulating material.)

1. A detection device for the performance of a pipeline heat-insulating material is characterized by comprising a heat-insulating performance detection pipeline and a detection instrument; the heat insulation performance detection pipeline is arranged at an outlet of a drainage door on a production and operation energy medium conveying pipeline or a conveying pipeline of a related energy medium experiment generating device;

the detection instrument comprises a flow orifice plate, a temperature compensation couple and a pressure transmitter which are arranged on the pipeline between the heat insulation performance detection pipeline and the drainage door; the heat insulation performance detection device also comprises an inlet pressure detection transmitter, an inlet temperature detection sensor, an outlet pressure detection transmitter and an outlet temperature detection sensor which are arranged at the inlet and the outlet of the heat insulation performance detection pipeline; the temperature sensor is arranged on the inner surface of the heat insulation material of the heat insulation performance detection pipeline;

the detection instruments are all connected with the control system, and the control system calculates the heat loss of the heat insulation material through the detection values of the detection instruments.

2. The device for detecting the performance of the pipeline heat-insulating material according to claim 1, wherein a pipeline outlet drain valve is further installed on the outlet pipeline of the heat-insulating performance detection pipeline, the detection instrument further comprises detection device drain valve inlet temperature detection sensors, detection device drain valve inlet pressure detection transmitters, detection device drain valve outlet pressure detection transmitters and detection device drain valve outlet temperature detection sensors, which are installed at the front end and the rear end of the pipeline outlet drain valve;

the detection instruments are also connected with a control system, and the control system calculates the resistance loss of the valve according to the detection values of the detection instruments.

3. The method for detecting the performance of the pipeline thermal insulation material as claimed in claim 1, wherein the method is a method for detecting and evaluating the performance of the pipeline thermal insulation material, and comprises the following steps:

1) before detection, the heat insulation material to be detected is wrapped on the heat insulation performance detection pipeline of the energy medium conveying pipeline;

2) opening a drain valve of the detection pipeline to the maximum opening value, then slowly opening the drain valve installed on the energy medium conveying pipeline until the drain valve is completely opened, and then slowly reducing the opening value of the drain valve of the detection pipeline until the drain valve of the detection pipeline is excessive or the opening value is 2% -4%; the opening state lasts for at least 2-3 hours;

3) after the opening degree of each valve is adjusted, starting testing, wherein the testing duration time is not less than 30 min;

calculating the heat dissipation loss Q of the heat-insulating material according to the detection data of the detection instrument, wherein the calculation formula is as follows:

in the formula:

Q-Heat dissipation, W;

h₁、h₂-expressing the convective heat transfer coefficient between the steam and the inner wall of the pipe, the convective heat transfer coefficient between the environment and the protective layer of the steam pipe, W/(m)²·℃)；

d₁、d₂-respectively representing the steam pipeline heat insulation inner diameter and the steam pipeline heat insulation outer diameter m;

lambda-represents the thermal conductivity of the insulation layer, W/(m DEG C);

t_P、t_a-respectively keeping the temperature of the inner surface of the thermal insulation material and the temperature of the outer surface of the thermal insulation material at the temperature of DEG C;

q_ij-pipe section flow, kg/s;

C_Pij-the average specific heat of the steam, kJ/(kg. DEG C);

t_i、t_j-representing the steam temperature, deg.c, at the beginning and at the end of the pipe section, respectively;

l is the length of the pipe section, m;

eta is the local heat dissipation loss correction coefficient;

among the above parameters, q_ij: the flow of the pipe section is detected by a flow orifice plate arranged on the pipeline between the heat insulation performance detection pipeline and the drainage door, and a temperature compensation couple and a pressure transmitter correct the flow value measured by the flow orifice plate under specific temperature and pressure;

t_i、t_jrespectively detected by an inlet temperature detection sensor and an outlet temperature detection sensor which are arranged at an inlet and an outlet of the heat insulation performance detection pipeline;

C_Pijthe detection values of an inlet pressure detection transmitter, an inlet temperature detection sensor, an outlet pressure detection transmitter and an outlet temperature detection sensor which are arranged at the inlet and the outlet of the heat insulation performance detection pipeline are obtained by looking up a table through a water vapor property table;

t_P、t_athe temperature measurement is carried out by a temperature measurement sensor arranged on the inner surface of the heat insulation material of the heat insulation performance detection pipeline and a temperature measurement sensor arranged on the outer surface of the heat insulation material;

the heat dissipation loss Q of the heat insulation material is an evaluation index of the performance of the pipeline heat insulation material.

Technical Field

The invention relates to the technical field of heat preservation and energy conservation of pipelines in the metallurgical and petrochemical industries, in particular to a device and an evaluation method for detecting the performance of a pipeline heat preservation material.

Background

Metallurgy, petrochemical industry possess a large amount of energy medium pipeline, and some energy media cause very big heat loss and energy level to reduce because pipeline self heat dissipation in transportation process, especially steam pipeline. In order to reduce the energy loss and improve the energy utilization efficiency, with the progress of the production process and the development of material technology, a plurality of novel pipeline heat-insulating materials are produced. The heat conductivity coefficient of the materials is lower than that of the currently used aluminum silicate fiber products, the price is relatively high, and the popularization and the application of the materials are not very good. The main reason is that the evaluation method of the use effect is unreasonable.

The common evaluation method is to select a small section of the running energy medium conveying pipeline, replace the original heat insulation material with a novel heat insulation material, and detect the surface temperature of the running energy medium conveying pipeline by using an infrared thermometer or a thermal imager after running for a period of time. Although the method can detect the surface temperature of the novel heat-insulating material and evaluate the use effect of the novel heat-insulating material, the detection result of the infrared imaging temperature measurement technology is related to factors such as the measurement distance, the roughness of the surface material of a measured object and the like, so that a large measurement error is easily caused, the measurement precision is influenced, and the reasonable economic thickness cannot be checked, so that the material investment of an enterprise is increased, and the popularization and the application of the novel heat-insulating material are restricted. Therefore, it is necessary to develop a method and a device for evaluating the performance of the pipeline thermal insulation material with high test precision.

Disclosure of Invention

In order to overcome the defects in the background art, the invention provides a device and an evaluation method for detecting the performance of a pipeline heat-insulating material, and provides an effective means for improving the performance detection method of the pipeline heat-insulating material and verifying the use effect of the economic thickness of the heat-insulating material. A feasible inspection platform is established for popularization and application of the novel energy medium conveying pipeline heat-insulating material.

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

a detection device for the performance of a pipeline heat-insulating material comprises a heat-insulating performance detection pipeline and a detection instrument; the heat insulation performance detection pipeline is arranged at an outlet of a drainage door on a production and operation energy medium conveying pipeline or a conveying pipeline of a related energy medium experiment generating device;

the detection instrument comprises a flow orifice plate, a temperature compensation couple and a pressure transmitter which are arranged on the pipeline between the heat insulation performance detection pipeline and the drainage door; the heat insulation performance detection device also comprises an inlet pressure detection transmitter, an inlet temperature detection sensor, an outlet pressure detection transmitter and an outlet temperature detection sensor which are arranged at the inlet and the outlet of the heat insulation performance detection pipeline; the temperature sensor is arranged on the inner surface of the heat insulation material of the heat insulation performance detection pipeline;

the detection instruments are all connected with the control system, and the control system calculates the heat loss of the heat insulation material through the detection values of the detection instruments.

Furthermore, the outlet pipeline of the thermal insulation performance detection pipeline is also provided with a detection pipeline outlet drain valve, the detection instrument further comprises detection device drain door inlet temperature detection sensors arranged at the front end and the rear end of the detection pipeline outlet drain valve, a detection device drain door inlet pressure detection transmitter, a detection device drain door outlet pressure detection transmitter and a detection device drain door outlet temperature detection sensor;

the detection instruments are also connected with a control system, and the control system calculates the resistance loss of the valve according to the detection values of the detection instruments.

The method of the device for detecting the performance of the pipeline heat-insulating material is a method for detecting and evaluating the performance of the pipeline heat-insulating material, and specifically comprises the following steps:

1) before detection, the heat insulation material to be detected is wrapped on the heat insulation performance detection pipeline of the energy medium conveying pipeline;

2) opening a drain valve of the detection pipeline to the maximum opening value, then slowly opening the drain valve installed on the energy medium conveying pipeline until the drain valve is completely opened, and then slowly reducing the opening value of the drain valve of the device until the drain valve 8 of the device is excessive or the opening value is 2% -4%; the opening state lasts for at least 2-3 hours;

3) after the opening degree of each valve is adjusted, starting testing, wherein the testing duration time is not less than 30 min;

calculating the heat dissipation loss Q of the heat-insulating material according to the detection data of the detection instrument, wherein the calculation formula is as follows:

in the formula:

Q-Heat dissipation, W;

h₁、h₂-expressing the convective heat transfer coefficient between the steam and the inner wall of the pipe, the convective heat transfer coefficient between the environment and the protective layer of the steam pipe, W/(m)²·℃)；

d₁、d₂-respectively representing the steam pipeline heat insulation inner diameter and the steam pipeline heat insulation outer diameter m;

lambda-represents the thermal conductivity of the insulation layer, W/(m DEG C);

t_P、t_a-respectively keeping the temperature of the inner surface of the thermal insulation material and the temperature of the outer surface of the thermal insulation material at the temperature of DEG C;

q_ij-pipe section flow, kg/s;

C_Pij-the average specific heat of the steam, kJ/(kg. DEG C);

t_i、t_j-representing the steam temperature, deg.c, at the beginning and at the end of the pipe section, respectively;

l is the length of the pipe section, m;

eta is the local heat dissipation loss correction coefficient;

among the above parameters, q_ij: the flow of the pipe section is detected by a flow orifice plate arranged on the pipeline between the heat insulation performance detection pipeline and the drainage door, and a temperature compensation couple and a pressure transmitter correct the flow value measured by the flow orifice plate under specific temperature and pressure;

t_i、t_jrespectively detected by an inlet temperature detection sensor and an outlet temperature detection sensor which are arranged at an inlet and an outlet of the heat insulation performance detection pipeline;

C_Pijthe detection values of an inlet pressure detection transmitter, an inlet temperature detection sensor, an outlet pressure detection transmitter and an outlet temperature detection sensor which are arranged at the inlet and the outlet of the heat insulation performance detection pipeline are obtained by looking up a table through a water vapor property table;

t_P、t_athe temperature measurement is carried out by a temperature measurement sensor arranged on the inner surface of the heat insulation material of the heat insulation performance detection pipeline and a temperature measurement sensor arranged on the outer surface of the heat insulation material;

the heat dissipation loss Q of the heat insulation material is an evaluation index of the performance of the pipeline heat insulation material.

Compared with the prior art, the invention has the beneficial effects that:

the invention can truly simulate the running state of the energy medium in the pipeline and the heat dissipation process of the energy medium in the pipeline. A reliable detection platform is provided for the heat insulation material of the energy medium conveying pipeline, and the mode that only one section of experiment development mode is selected on the existing running pipeline is eliminated. Has positive significance for the application and popularization of novel heat-insulating materials.

Drawings

FIG. 1 shows a device for detecting the heat insulation performance of an energy medium conveying pipeline;

FIG. 2 is a schematic view of the installation of an internal and external temperature measurement couple of a thermal insulation performance detection thermal insulation material;

1-energy medium conveying pipeline, 2-drain valve, 3-flow orifice plate, 4-temperature compensation couple, 5-pressure transmitter, 6-energy medium conveying pipeline thermal insulation performance detection pipeline, 7-flange, 8-device drain valve, 9-support, 10-thermal insulation material, 11-energy medium conveying pipeline thermal insulation performance detection pipeline inlet pressure detection transmitter, 12-energy medium conveying pipeline thermal insulation performance detection pipeline inlet temperature detection sensor, 13-energy medium conveying pipeline thermal insulation performance detection pipeline outlet pressure detection transmitter, 14-energy medium conveying pipeline thermal insulation performance detection pipeline outlet temperature detection sensor, 15-energy medium conveying pipeline thermal insulation performance detection device drain valve inlet temperature detection sensor, 16-energy medium conveying pipeline thermal insulation performance detection device drain valve inlet pressure detection transmitter, 17-a pressure detection transmitter of a drainage door outlet of the heat insulation performance detection device of the energy medium conveying pipeline, and 18-a temperature detection sensor of a drainage door outlet of the heat insulation performance detection device of the energy medium conveying pipeline; 19-the outer wall of the heat-insulation detection pipeline of the energy medium conveying pipeline, 20-the outermost protective cover, 21-the temperature sensor on the inner surface of the heat-insulation material, and 22-the temperature sensor on the outer surface of the heat-insulation material.

Detailed Description

The following detailed description of the present invention will be made with reference to the accompanying drawings.

The invention mainly aims to provide an effective detection and evaluation method for a feasible experimental platform for detecting the performance of the heat-insulating material of the energy medium conveying pipeline. The invention relies on an energy medium conveying pipeline heat preservation detection device. The device can be arranged on an energy medium conveying pipeline for production and operation, and can also be connected to a conveying pipeline of a related energy medium experiment generating device. The device can simulate the flowing state of an energy medium in a conveying pipeline, and can also detect the resistance loss of different types of valves, and the change rules of the pressure and the temperature before and after the valves.

As shown in figures 1-2, the device of the invention consists of an energy medium conveying pipeline heat preservation performance detection pipeline 6 and a related detection instrument. The devices being installed in production operation, or prepared in the laboratoryThe corresponding energy medium pipeline 1 has the outlet of the drainage door 2, and the installation mode can be selected to be welding or connected by a flange. And a flow orifice plate 3, a temperature compensation couple 4 and a pressure transmitter 5 are arranged on the pipeline connected with the heat insulation performance detection pipeline 6 of the energy medium conveying pipeline. The temperature compensation couple 4 and the pressure transmitter 5 mainly function to correct the flow value measured by the flow orifice plate 3 under a specific temperature and pressure. The length of the pipeline arranged at the front part of the flow orifice plate 3 is ensured to be not less than 10 times of the pipe diameter size, and the length of the pipeline arranged at the rear part of the flow orifice plate 3 is not less than 5 times of the pipe diameter size. If the pipe diameters of the heat insulation performance detection pipeline 6 of the energy medium conveying pipeline and the pipeline behind the flow pore plate 3 are different, the pipeline behind the flow pore plate 3 can be welded and changed in diameter, and then the pipeline is connected through the flange 7. An energy medium conveying pipeline heat insulation performance detection pipeline 6 is provided with an energy medium conveying pipeline heat insulation performance detection pipeline inlet pressure detection transmitter 11, an energy medium conveying pipeline heat insulation performance detection pipeline inlet temperature detection sensor 12, an energy medium conveying pipeline heat insulation performance detection pipeline outlet pressure detection transmitter 13 and an energy medium conveying pipeline heat insulation performance detection pipeline outlet temperature detection sensor 14 at an inlet and an outlet. The pipe diameter of the heat insulation performance detection pipeline 6 of the energy medium conveying pipeline can be determined according to actual conditions, and can beThe pipeline of,The pipeline of,And a pipe lineThe conduit of (a), etc. A drain valve 8 of a thermal insulation performance evaluation device is arranged at the rear part of the thermal insulation performance detection pipeline 6 of the energy medium conveying pipeline, the pipe diameter of the thermal insulation performance detection pipeline 6 of the energy medium conveying pipeline is different from the pipe diameter of a connecting pipeline of the drain valve 8 of the thermal insulation performance evaluation device, and the heat insulation performance detection pipeline can be connected with the drain valve 8 through a mounting flange 7 and weldingThe pipelines are connected in a reducing mode. A flange 7 is welded at the outlet of the heat insulation performance detection pipeline 6 of the energy medium conveying pipeline, and the front end of the pipeline in front of a drain valve 8 of the heat insulation performance evaluation device is welded with a reducing pipe. The form of the drain valve 8 of the thermal insulation performance evaluation device can be a gate valve and a stop valve. The drift diameter of the valve can be DN50, DN65 and the like, and the pressure parameters are determined according to the delivery pressure of the energy medium. The heat preservation performance evaluation device is characterized in that a heat preservation performance detection device, namely a drain door inlet temperature detection sensor 15, an energy medium transmission pipeline heat preservation performance detection device, namely a drain door inlet pressure detection transmitter 16, an energy medium transmission pipeline heat preservation performance detection device, namely a drain door outlet pressure detection transmitter 17 and an energy medium transmission pipeline heat preservation performance detection device, namely a drain door outlet temperature detection sensor 18 are arranged on pipelines in front of and behind a drain valve 8. A temperature sensor 21 on the inner surface of the heat insulation material and a temperature sensor 22 on the outer surface of the heat insulation material are arranged on the heat insulation material wrapped by the heat insulation performance detection pipeline 6 of the energy medium conveying pipeline.

The detection method for evaluating the performance of the pipeline heat-insulating material comprises the following steps:

1) before detection, the heat-insulating material to be detected is wrapped on the heat-insulating performance detection pipeline 6 of the energy medium conveying pipeline.

2) And then opening the drain valve 8 of the device to the maximum opening value, then slowly opening the drain valve 2 arranged on the energy medium conveying pipeline 1 until the drain valve 2 is completely opened, and then slowly reducing the opening value of the drain valve 8 of the device until the drain valve 8 of the device is excessive or the opening value is 2-4%. In order to saturate the heat storage capacity of the heat insulation material wrapped by the heat insulation performance detection pipeline 6 of the energy medium conveying pipeline, the opening states of the drain valve 2 and the drain valve 8 at least last for 2-3 times.

3) During testing, firstly, an insulating material inner surface temperature sensor 21 and an insulating material outer surface temperature sensor 22 are installed on an insulating material wrapped by an energy medium conveying pipeline insulating property detection pipeline 6, and wires for transmitting signals of a flow orifice plate 3, a temperature compensation couple 4, a pressure transmitter 5, an energy medium conveying pipeline insulating property detection pipeline inlet pressure detection transmitter 11, an energy medium conveying pipeline insulating property detection pipeline inlet temperature detection sensor 12, an energy medium conveying pipeline insulating property detection pipeline outlet pressure detection transmitter 13, an energy medium conveying pipeline insulating property detection pipeline outlet temperature detection sensor 14, the insulating material inner surface temperature sensor 21 and the insulating material outer surface temperature sensor 22 are connected to a paperless recorder. Then the opening degree of the drain valve 8 is increased, and the opening degree value is determined according to the values of the pressure detection transmitter 11 at the inlet of the heat insulation performance detection pipeline 6 at the outlet and the inlet of the heat insulation performance detection pipeline of the energy medium transmission pipeline and the pressure detection transmitter at the outlet of the heat insulation performance detection pipeline of the energy medium transmission pipeline. And (5) starting the experiment after the opening of each valve is adjusted, wherein the experiment duration time is not less than 30 min. And (3) recording the detection data of the mounting instrument of each measuring point while the experiment is carried out, and calculating the heat dissipation loss of the heat insulation material by using the relevant knowledge of heat transfer. The calculation formula is as follows:

in the formula:

Q-Heat dissipation, W;

d₁、d₂-respectively representing the steam pipeline heat insulation inner diameter and the steam pipeline heat insulation outer diameter m;

lambda-represents the thermal conductivity of the insulating layer, W/(m DEG C), respectively;

t_P、t_a-temperature of the inner surface of the insulation material, temperature of the outer surface of the insulation material, ° c;

q_ij-pipe section flow, kg/s;

C_Pij-the average specific heat of the steam, kJ/(kg. DEG C);

t_i、t_j-representing the steam temperature, deg.c, at the beginning and at the end of the pipe section, respectively;

l is the length of the pipe section, m;

eta-local heat dissipation loss correction coefficient.

In addition, the device can detect the local resistance loss coefficients of different types of valves. And when the performance of the heat-insulating material is detected, the drain valve 8 connected with the tail end of the device is utilized to carry out related detection. Before testing, a drainage door inlet temperature detection sensor 15, a drainage door inlet pressure detection transmitter 16, an energy medium conveying pipeline thermal insulation performance detection device drainage door outlet pressure detection transmitter 17 and an energy medium conveying pipeline thermal insulation performance detection device drainage door outlet temperature detection sensor 18 which are arranged in front of and behind a drainage valve 8 are connected into a paperless recorder. During testing, the opening degree of the drain valve 8 of the device is adjusted, detection data of the opening degrees of the drain valves 8 of different devices are recorded, and the local resistance loss coefficient of the valve is regressed by using a Bernoulli equation and a least square method.

The specific embodiment is as follows:

the pipe diameter of the pipeline 6 is detected by the heat insulation performance of the energy medium conveying pipelineThe transmission medium is steam, the parameters detected and transmitted by the pressure transmitter 5, the temperature compensation couple 4 and the flow orifice plate 3 are respectively 0.4MPa, 190 ℃ and 40t/h, the wrapping thickness is 140mm, and the material is rock wool and thermal insulation material of slag wool products as examples, according to the actual test result, the pressure detected by the pressure detection transmitter 11 at the inlet of the thermal insulation performance detection pipeline of the energy medium transmission pipeline is 0.393MPa, the temperature detected by the temperature detection sensor 12 at the inlet of the thermal insulation performance detection pipeline of the energy medium transmission pipeline is 188.32 ℃, the pressure detected by the pressure detection transmitter 13 at the outlet of the thermal insulation performance detection pipeline of the energy medium transmission pipeline is 0.387MPa, the temperature detected by the temperature detection sensor 14 at the outlet of the thermal insulation performance detection pipeline of the energy medium transmission pipeline is 186.98 ℃, the temperature detected by the temperature measurement sensor 21 at the inner surface of the thermal insulation material is 189.14 ℃, the temperature detected by the temperature measurement sensor 22 at the outer surface of the thermal insulation material is 47.84 ℃, the average heat flow density of the pipeline calculated by the formula is 136.7W/m²The average temperature of the outermost shell was 45.3 ℃. Package thickness 140mm, the material is a novel heat-insulating material of high-temperature glass wool product, according to the actual test result, the pressure detected by the pressure detection transmitter 11 at the inlet of the heat-insulating performance detection pipeline of the energy medium transmission pipeline is 0.396MPa, the temperature detected by the temperature detection sensor 12 at the inlet of the heat-insulating performance detection pipeline of the energy medium transmission pipeline is 189.02 ℃, the pressure detected by the pressure detection transmitter 13 at the outlet of the heat-insulating performance detection pipeline of the energy medium transmission pipeline is 0.389MPa, the temperature detected by the temperature detection sensor 14 at the outlet of the heat-insulating performance detection pipeline of the energy medium transmission pipeline is 188.18 ℃, the temperature detected by the temperature measurement sensor 21 at the inner surface of the heat-insulating material is 189.46 ℃, the temperature detected by the temperature measurement sensor 22 at the outer surface of the heat-insulating material is 43.32 ℃, and the average heat flow density of the pipeline calculated by the formula is 129.2W/m²The average temperature of the outermost iron plate was 41.2 ℃.

The above embodiments are implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are given, but the scope of the present invention is not limited to the above embodiments. The methods used in the above examples are conventional methods unless otherwise specified.