Method for measuring air temperature field of air outlet of brake resistor device

Abstract

The invention relates to an air outlet temperature field measuring device, in particular to a method for measuring an air temperature field of an air outlet of a brake resistor device, which is characterized in that a temperature measuring plate with a ventilation opening is made of 304 stainless steel and is arranged at the air outlet of a forced air cooling brake resistor device, so that the temperature measuring plate is heated by cooling air when the brake resistor device works, and an oxidation film is generated on the surface. Because the thickness of the oxide film is related to the temperature of the cooling air and influences the interference color, the temperature distribution of the cooling air at the air outlet, namely the air temperature field of the air outlet, can be deduced by using the color distribution of the oxide film generated after the temperature measuring plate is oxidized by the cooling air at high temperature. Materials are low in cost and easy to obtain; the holes of the temperature measuring plate are dense, so that the influence on the flowing state of cooling air is small, and the working condition during temperature measurement is close to the normal working state of the brake resistor device.

Description

Technical Field

[0001] The invention relates to a device for measuring temperature field, in particular to a method for measuring the air temperature field at an air outlet of a braking resistor device. Background Art

[0002] The power of the locomotive brake resistor device is getting bigger and bigger, and the problem of resistor burning is getting more and more attention. Among them, the uneven heating of the resistor belt caused by the uneven distribution of cooling airflow in the flow channel accounts for a large proportion of the burning. The distribution of cooling airflow in the flow channel and the heat dissipation effect on the resistor belt can be represented by the cooling air temperature field at the air outlet.

[0003] Currently, there is no direct means to measure the cooling air temperature field at the air outlet under working conditions. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for measuring the air temperature field at the air outlet of a brake resistor device, which has low material cost and is easy to obtain; the temperature measuring plate has dense openings, which has little effect on the flow state of cooling air, and makes the working condition during temperature measurement close to the normal working state of the brake resistor device.

[0005] The 304 stainless steel temperature measuring plate is made of 304 stainless steel, has a flat and smooth surface, is degreased and decontaminated, and has naturally formed oxide scale removed, and is not subjected to treatments such as coloring, electroplating, and coating.

[0006] The technical solution of the present invention is: to relate to a method for measuring the air temperature field at the air outlet of a brake resistor device, which is characterized by comprising: a 304 stainless steel temperature measuring plate, an air outlet of a brake resistor device, a spectrophotometer and the following steps: 1) Choose 304 stainless steel temperature measuring plate material without coloring, electroplating or coating; 2) The 304 stainless steel temperature measuring plate is made of 304 stainless steel. The surface of the 304 stainless steel temperature measuring plate is mechanically ground and polished, and the surface is smooth; 3) Degrease the surface of the 304 stainless steel temperature measuring plate to remove surface oil, dust and other pollutants; 4) The 304 stainless steel temperature measuring plate is pickled to remove the naturally formed oxide scale; 5) Open evenly distributed vents on the 304 stainless steel temperature measuring plate; 6) Use a punching process that does not generate heat to process vents on the 304 stainless steel temperature measuring plate; 7) The evenly distributed vents occupy more than 70% of the area of ​​the 304 stainless steel temperature measuring plate, which makes the airflow blocking area smaller and does not affect the airflow state;

[0007] 8) Install the 304 stainless steel temperature measuring plate at the air outlet of the brake resistor device. After installation, the 304 stainless steel temperature measuring plate should be perpendicular to the cooling air flow direction of the air outlet; 9) Turn on the brake resistor device under the working condition where temperature measurement is required, and keep it on for 20 minutes or more after the working condition stabilizes, so that the 304 stainless steel temperature measuring plate can be heated and oxidized in the cooling air; 10) After the working condition is stable and lasts for 20 minutes or more, turn off the brake resistor device and remove it after the 304 stainless steel temperature measuring plate cools down naturally; 11) Use a spectrophotometer to measure the L* value and a* value of the windward surface of the 304 stainless steel temperature measuring plate, and record the position of the measuring point; take multiple measurement points to obtain multiple point data; 12) The air temperature field at the air outlet (1) of the brake resistor device is obtained from the position coordinates of the measuring point and the calculated temperature value of the point.

[0008] The step 12) includes: Substitute the measured L* value into the following formula (1) to obtain the temperature value at that position; T=k1(L*)³+k2(L*) 2 +k3L*+k4 ……(1) In the formula, T is the maximum temperature experienced at that location; L* is the L* value of the position measured by the spectrophotometer; k1, k2, k3, k4 are coefficients, and the optimal value of the coefficient is: k1=-1.6585×10 -2 , k2=2.3855, k3= -117.6304, k4= 2619.8094; The air temperature field of the air outlet 1 of the brake resistor device is obtained from the position coordinates of the measuring point and the calculated temperature value of the point.

[0009] Substitute the measured a* value into the following formula (2) to obtain the temperature value at that position: T = k1(a*) 3 +k2(a*) 2 +k3(a*)+k4……(2) In the formula, T is the maximum temperature experienced at that location; a* is the a* value of the position measured by the spectrophotometer; k1, k2, k3, k4 are coefficients, and the optimal value of the coefficient is: k1=6.1406×10 -2 , k2= -2.7541, k3=55.0889, k4=267.4303; The air temperature field at the air outlet of the brake resistor device can be obtained by the position coordinates of the measuring point and the calculated temperature value of the point.

[0010] The advantages of the present invention are: the temperature measuring plate used is made of 304 stainless steel, the material cost is low and it is easy to obtain; the temperature measuring plate has dense openings, which has little effect on the flow state of cooling air, so that the working condition during temperature measurement is close to the normal working state of the brake resistor device. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of an embodiment of the present invention.

[0012] In the figure, 1. Air outlet of the brake resistor device; 2. 304 stainless steel temperature measuring plate; 3. Spectrometer; 4. Ventilation port. DETAILED DESCRIPTION

[0013] The following will describe the implementation methods of the present invention in detail with reference to the accompanying drawings and embodiments, so as to fully understand and implement the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects. It should be noted that as long as there is no conflict, the various embodiments of the present invention and the various features in the embodiments can be combined with each other, and the technical solutions formed are all within the protection scope of the present invention.

[0014] Meanwhile, in the following description, many specific details are set forth for the purpose of explanation to provide a thorough understanding of the embodiments of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without the specific details or the specific manner described herein.

[0015] When 304 stainless steel and its products are working in a high temperature environment under air atmosphere, a very thin and dense oxide film will be formed on its surface due to high temperature oxidation. This oxide film is colorless and transparent, but due to the principle of light interference, it will show interference color, and the color of the interference color is related to the thickness of the oxide film. After 304 stainless steel and its products experience high temperature oxidation for a certain period of time in air atmosphere, the thickness of the oxide film produced is related to the highest temperature it has experienced.

[0016] Applying the above principle, the present invention provides a device for measuring the air temperature field at the air outlet of a brake resistor device. The analysis method of the present invention is now described through the following embodiments. Example 1

[0017] like Figure 1 As shown, the present invention relates to a method for measuring the air temperature field at the air outlet of a brake resistor device, which is characterized by comprising a 304 stainless steel temperature measuring plate 2, an air outlet of a brake resistor device 1, a spectrophotometer 3 and the following steps: 1) Choose 304 stainless steel temperature measuring plate 2 material without coloring, electroplating or coating; 2) The 304 stainless steel temperature measuring plate 2 is made of 304 stainless steel. The surface of the 304 stainless steel temperature measuring plate 2 is processed by mechanical grinding and polishing, and the surface is flat and smooth; 3) Degreasing the surface of the 304 stainless steel temperature measuring plate 2 to remove surface oil, dust and other pollutants; 4) The 304 stainless steel temperature measuring plate 2 is pickled to remove the naturally formed oxide scale; 5) Open evenly distributed vents 4 on the 304 stainless steel temperature measuring plate 2; 6) Use a punching process that does not generate heat to process the vent 4 on the 304 stainless steel temperature measuring plate 2; 7) The evenly distributed vents 4 occupy more than 70% of the area of ​​the 304 stainless steel temperature measuring plate 2, which makes the airflow blocking area smaller and does not affect the airflow state; 8) Install the 304 stainless steel temperature measuring plate 2 at the air outlet 1 of the brake resistor device. After installation, the 304 stainless steel temperature measuring plate 2 is perpendicular to the cooling air flow direction of the air outlet; 9) Turn on the brake resistor device under the working condition where temperature measurement is required, and keep it on for 20 minutes or more after the working condition stabilizes, so that the 304 stainless steel temperature measuring plate 2 is heated and oxidized in the cooling air; 10) After the working condition is stable and lasts for 20 minutes or more, turn off the brake resistor device and remove it after the 304 stainless steel temperature measuring plate 2 cools down naturally; 11) Use the spectrophotometer 3 to measure the L* value of the windward surface of the 304 stainless steel temperature measuring plate 2, and record the position of the measuring point; take multiple measurement points to obtain multiple point data; 12) Substitute the measured L* value into the following formula (1) to obtain the temperature value at that position; T=k1(L*)³+k2(L*) 2 +k3L*+k4 ……(1) In the formula, T is the maximum temperature experienced at that location; L* is the L* value of the position measured by the spectrophotometer; k1, k2, k3, k4 are coefficients, and the optimal value of the coefficient is: k1=-1.6585×10 -2 , k2=2.3855, k3= -117.6304, k4= 2619.8094; The air temperature field of the air outlet 1 of the brake resistor device is obtained from the position coordinates of the measuring point and the calculated temperature value of the point. Example 2

[0018] like Figure 1 As shown, the present invention relates to a device for measuring the air temperature field at the air outlet of a brake resistor device, which is characterized by comprising a 304 stainless steel temperature measuring plate 2, an air outlet of a brake resistor device 1, a spectrophotometer 3 and the following steps: 1) Choose 304 stainless steel temperature measuring plate 2 material without coloring, electroplating or coating; 2) The 304 stainless steel temperature measuring plate 2 is made of 304 stainless steel. The surface of the 304 stainless steel temperature measuring plate 2 is processed by mechanical grinding and polishing, and the surface is flat and smooth; 3) Degreasing the surface of the 304 stainless steel temperature measuring plate 2 to remove surface oil, dust and other pollutants; 4) The 304 stainless steel temperature measuring plate 2 is pickled to remove the naturally formed oxide scale; 5) Open evenly distributed vents 4 on the 304 stainless steel temperature measuring plate 2; 6) Use a punching process that does not generate heat to process the vent 4 on the 304 stainless steel temperature measuring plate 2; 7) The evenly distributed vents 4 occupy more than 70% of the area of ​​the 304 stainless steel temperature measuring plate 2, which makes the airflow blocking area smaller and does not affect the airflow state; 8) Install the 304 stainless steel temperature measuring plate 2 at the air outlet 1 of the brake resistor device. After installation, the 304 stainless steel temperature measuring plate 2 is perpendicular to the cooling air flow direction of the air outlet; 9) Turn on the brake resistor device under the working condition where temperature measurement is required, and keep it on for 20 minutes or more after the working condition stabilizes, so that the 304 stainless steel temperature measuring plate 2 is heated and oxidized in the cooling air; 10) After the working condition is stable and lasts for 20 minutes or more, turn off the brake resistor device and remove it after the 304 stainless steel temperature measuring plate 2 cools down naturally; 11) Use the spectrophotometer 4 to measure the a* value of the windward surface of the 304 stainless steel temperature measuring plate 2, and record the position of the measuring point, take multi-point measurements, and obtain multi-point data; 12) Substitute the measured a* value into the following formula (2) to obtain the temperature value at that position: T = k1(a*) 3 +k2(a*) 2 +k3(a*)+k4……(2) In the formula, T is the maximum temperature experienced at that location; a* is the a* value of the position measured by the spectrophotometer; k1, k2, k3, k4 are coefficients, and the optimal value of the coefficient is: k1=6.1406×10 -2 , k2= -2.7541, k3=55.0889, k4=267.4303; The air temperature field at the air outlet of the brake resistor device can be obtained by the position coordinates of the measuring point and the calculated temperature value of the point.

[0019] The measuring method of the present invention is based on the principle that when 304 stainless steel and its products work in a high temperature environment under an air atmosphere, a very thin and dense oxide film will be produced on its surface due to high temperature oxidation. This oxide film is colorless and transparent, but due to the interference principle of light, it will show interference color, and the color of the interference color is related to the thickness of the oxide film; after 304 stainless steel and its products experience high temperature oxidation for a certain period of time under an air atmosphere, the thickness of the oxide film produced is related to the highest temperature it has experienced. A temperature measuring plate with a vent is made of 304 stainless steel and installed at the air outlet of a forced air-cooled brake resistor device, so that it is heated by cooling air when the brake resistor device is working, and an oxide film is produced on the surface. Because the thickness of the oxide film is related to the temperature of the cooling air, and the thickness of the oxide film affects the interference color, the color distribution of the oxide film produced after the temperature measuring plate is oxidized by cooling air at high temperature can be used to deduce the temperature distribution of the cooling air at the air outlet, that is, the air temperature field at the air outlet.

[0020] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for measuring the air temperature field at the air outlet of a brake resistor device, characterized in that: The method comprises a 304 stainless steel temperature measuring plate (2), an air outlet of a brake resistor device (1), a spectrophotometer (3) and the following steps: 1) Select 304 stainless steel temperature measuring plate (2) material that is not colored, electroplated or coated; 2) The 304 stainless steel temperature measuring plate (2) is made of 304 stainless steel. The surface of the 304 stainless steel temperature measuring plate (2) is processed by mechanical grinding and polishing, and the surface is flat and smooth; 3) Degreasing the surface of the 304 stainless steel temperature measuring plate (2) to remove surface oil, dust and other pollutants; 4) The 304 stainless steel temperature measuring plate (2) is pickled to remove the naturally formed oxide scale; 5) Open evenly distributed ventilation holes (4) on the 304 stainless steel temperature measuring plate (2); 6) Processing the vent (4) on the 304 stainless steel temperature measuring plate (2) using a punching process that does not generate heat; 7) The evenly distributed ventilation holes (4) occupy more than 70% of the area of ​​the 304 stainless steel temperature measuring plate (2), so that the airflow blocking area is small and does not affect the airflow state; 8) Install the 304 stainless steel temperature measuring plate (2) at the air outlet (1) of the brake resistor device. After installation, the 304 stainless steel temperature measuring plate (2) is perpendicular to the cooling air flow direction of the air outlet; 9) Turn on the brake resistor device under the working condition that requires temperature measurement, and keep it on for 20 minutes or more after the working condition stabilizes, allowing the 304 stainless steel temperature measuring plate (2) to be heated and oxidized in the cooling air; 10) When the working condition is stable and lasts for 20 minutes or more, turn off the brake resistor device and remove it after the 304 stainless steel temperature measuring plate (2) cools down naturally; 11) Use a spectrophotometer (3) to measure the L* value of the windward surface of the 304 stainless steel temperature measuring plate (2), and record the position of the measuring point; take multiple measurement points to obtain multiple point data; 12) The air temperature field at the air outlet (1) of the brake resistor device is obtained from the position coordinates of the measuring point and the calculated temperature value of the point.

2. The method for measuring the air temperature field at the air outlet of a brake resistor device according to claim 1 is characterized in that: The step 12) includes: Substitute the measured L* value into the following formula (1) to obtain the temperature value at that position; T=k1(L*)³+k2(L*) 2 +k3L*+k4 ……(1) In the formula, T is the maximum temperature experienced at that location; L* is the L* value of the position measured by the spectrophotometer; k1, k2, k3, k4 are coefficients, and the optimal value of the coefficient is: k1=-1.6585×10 -2 , k2=2.3855, k3= -117.6304, k4= 2619.8094; The air temperature field of the air outlet 1 of the brake resistor device is obtained from the position coordinates of the measuring point and the calculated temperature value of the point.

3. The method for measuring the air temperature field at the air outlet of a brake resistor device according to claim 1, wherein: Substitute the measured a* value into the following formula (2) to obtain the temperature value at that position: T= k1(a*) 3 +k2(a*) 2 +k3(a*)+k4……(2) In the formula, T is the maximum temperature experienced at that location; a* is the a* value of the position measured by the spectrophotometer; k1, k2, k3, k4 are coefficients, and the optimal value of the coefficient is: k1=6.1406×10 -2 , k2= -2.7541, k3= 55.0889, k4=267.4303; The air temperature field at the air outlet of the brake resistor device can be obtained by the position coordinates of the measuring point and the calculated temperature value of the point.

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