An arrayed bolometer for measuring the radiant heat flux of a plasma

Abstract

The application discloses an array type radiation heat probe for measuring plasma radiation heat flow density, which comprises a detection element, a thermocouple, a mounting base, a fixing base and a fixing buckle. The mounting base and the fixing base are provided with through holes; the mounting base is placed on the fixing base; the fixing buckle is welded on the fixing base; the thermocouple penetrates through the mounting base, the fixing base and the fixing buckle, and a detection head is exposed at the mounting base; the thermocouple is fixed through the fixing buckle; the detection element is placed on the mounting base and is fixedly contacted with the detection head of the thermocouple through ceramic screws. The application solves the problem that the thermocouple cannot directly measure the heat flow density, utilizes the heat conduction of the copper sheet and the temperature measurement of the thermocouple, adopts an array type distribution, and indirectly measures the radial radiation heat flow density which is radiated from the plasma to the vacuum wall due to the ion diffusion.

Description

Technical Field

[0001] This invention belongs to the field of plasma radiation heat flux measurement, and in particular relates to an array-type radiation heat probe for measuring plasma radiation heat flux density. Background Technology

[0002] In current radio frequency linear plasma devices, the output power of the radio frequency power supply is coupled into the plasma through a transmission network (matching network + radio frequency antenna). A small portion of the power absorbed by the plasma is dissipated as radiated photons, while the majority is transported, diffused, and interacts with the walls, ultimately depositing as heat on the discharge tube and the downstream vacuum chamber walls. Measuring plasma energy balance and radiation loss is essential for understanding the device's operation.

[0003] The heat flux density deposited on the discharge tube can be measured by an infrared camera, while the heat flux deposited on the vacuum wall downstream of the device due to particle transport and diffusion cannot be directly measured by a thermocouple, but can be measured by a radiation thermal probe.

[0004] Existing methods for measuring heat flux density include metal thin-film radiation thermal detectors, but these detectors have high requirements for the metal thin film and are difficult to manufacture in-house. Therefore, this invention designs a radiation thermal probe with a simple fabrication process, easy to manufacture in the laboratory. The heat flux density on the downstream vacuum chamber wall can be calculated using a simple formula. Furthermore, the design incorporates an array arrangement, allowing for simultaneous measurement of heat flux data at different locations, ensuring accurate calculation results. Summary of the Invention

[0005] The purpose of this invention is to provide an array-type radiative heat probe for measuring plasma radiative heat flux density, which can more accurately measure the radiative heat flux density caused by particles diffusing away from the plasma and heading towards the vacuum wall, thus solving the problem that thermocouples cannot directly measure heat flux density.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An array-type radiative thermal probe for measuring plasma radiative heat flux density includes a detection element, a thermocouple, a mounting base, a fixing base, and a fixing clip.

[0008] The detection element has two threaded holes and is fixed to the mounting base by threads.

[0009] The mounting base has through holes along the thickness direction and is connected to the fixed base by threads.

[0010] The fixing buckle is welded to the fixing base;

[0011] The thermocouple passes through the mounting base and the through hole of the fixing base, and is fixed to the fixing base by a fixing buckle.

[0012] Furthermore, the detection element is a copper plate with a diameter of 10 mm and a thickness of 0.4 mm; the detection element has 1 mm through holes at both ends of its diameter.

[0013] Furthermore, the thermocouple is graduated by a K-type number, and the measuring head diameter is 1 mm.

[0014] Furthermore, the mounting base is a ceramic material with a length of 120mm, a width of 20mm, and a thickness of 10mm; the diameter of the through hole in the mounting base through the thermocouple is 1.1mm; the diameter of the threaded hole in the mounting base for fixing the detection element is 1mm and the depth is 5mm; the diameter of the through hole between the mounting base and the fixing base is 2mm.

[0015] Furthermore, the fixing base is made of 304 stainless steel with a length of 120mm, a width of 20mm, and a thickness of 10mm; the diameter of the through hole in the fixing base is 1.1mm.

[0016] Furthermore, the fixing buckle is made of 304 stainless steel and includes a hollow cylinder one with an inner diameter of 3mm, an outer diameter of 3.4mm, and a depth of 15mm, and a hollow cylinder two with an inner diameter of 5mm and an outer diameter of 10mm; the hollow cylinder one and the hollow cylinder two are connected by a structure with an inner diameter of 3mm, an outer diameter of 5mm, a chamfered conical platform in the middle, and external threads on the outside; the hollow cylinder two has internal threads inside.

[0017] Furthermore, the bottom of the fixing buckle is provided with a cube structure with a diagonal length of 10mm and a thickness of 1mm, and the opening in the middle of the cube structure is 1.1mm.

[0018] Beneficial effects:

[0019] This invention is used to measure the heat flux density distribution on the wall of the downstream vacuum chamber of a discharge chamber. Compared with existing metal thin-film radiation thermal detectors, it has a simpler manufacturing process, lower cost, and is more convenient for laboratory fabrication. The heat flux density on the downstream vacuum chamber wall can be calculated using a simple formula. Furthermore, the design incorporates an array arrangement, eliminating the need to move the detector back and forth, allowing simultaneous measurement of heat flux data at different locations and providing the spatial distribution of heat flux density. The numerical settings of various parameters in this invention enable a more compact detector design. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an array-type radiative thermal probe for measuring plasma radiative heat flux density according to the present invention.

[0021] Figure 2a , Figure 2bThis is a schematic diagram of the mounting base for an array-type radiative thermal probe used to measure plasma radiative heat flux density according to the present invention; wherein, Figure 2a This is a side view. Figure 2b This is a top view;

[0022] Figure 3 This is a schematic diagram of the fixed base structure of an array-type radiative heat probe for measuring plasma radiative heat flux density according to the present invention.

[0023] Figure 4 This is a schematic diagram of the fixing clip structure of an array-type radiative heat probe for measuring plasma radiative heat flux density according to the present invention.

[0024] Among them, 1-detection element; 2-thermocouple; 3-mounting base; 4-fixed base; 5-hollow cylinder two for fixing buckle; 6-hollow cylinder one for fixing buckle; 7-threaded hole for connecting the mounting base and the fixed base; 8-through hole for placing thermocouple; 9-threaded hole for fixing detection element. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] like Figure 1 As shown, the array-type radiative thermal probe for measuring plasma radiative heat flux density of the present invention includes a detection element 1, a thermocouple 2, a mounting base 3, a fixing base 4, and a fixing clip.

[0027] like Figures 1-3 As shown, the mounting base 3 has a row of arrayed through holes 8 for placing thermocouples. The fixing base 4 has a row of through holes 8 for placing thermocouples in the same position as the mounting base 3. The mounting base 3 and the fixing base 4 are connected by threaded holes 7 at four vertices for connecting the mounting base and the fixing base; the fixing clip is welded to the fixing base 4; the fixing clip consists of a hollow cylinder 6 and a hollow cylinder 5, the hollow cylinder 5 of the fixing clip has external threads and a chamfered conical platform inside to hold a fluororubber conical frustum.

[0028] like Figure 2a , Figure 2b , Figure 3 , Figure 4As shown, the detection element 1 is a copper plate with a diameter of 10mm and a thickness of 0.4mm; the detection element 1 has two 1mm through holes in its diameter direction; the thermocouple is of the K-type graduation, and the measuring head diameter is 1mm; the mounting base 3 is a ceramic material with a length of 120mm, a width of 20mm, and a thickness of 10mm. The diameter of the through hole 8 in the mounting base 3 for placing the thermocouple is 1.1mm; the diameter of the threaded hole in the mounting base 3 for fixing the detection element 1 is 1mm, and the depth is 5mm. The diameter of the through hole between the mounting base 3 and the fixing base 4 is 2mm; the fixing base 4 is a 304 stainless steel material with a length of 120mm, a width of 20mm, and a thickness of 10mm. The through hole diameter of the fixed base 4 is 1.1mm; the material of the fixing buckle is 304 stainless steel, and it is composed of a hollow cylinder 6 with an inner diameter of 3mm, an outer diameter of 3.4mm, and a depth of 15mm and a hollow cylinder 5 with an inner diameter of 5mm, an outer diameter of 10mm, and a depth of 15mm; the hollow cylinder 6 and the hollow cylinder 5 are connected by a conical platform with a chamfered middle section and external threads, which is a structure in which a fluororubber conical frustum is placed on the hollow cylinder 5; the hollow cylinder 5 has internal threads; the bottom of the fixing buckle has a cube structure with a diagonal length of 10mm and a thickness of 1mm, and the central opening of the cube structure is circular with a diameter of 1.1mm.

[0029] This invention sets eight detection element positions on the mounting base 3. The actual number of detection elements 1 and thermocouples can be designed on-site according to different needs. The shapes of the mounting base 3 and the fixed base 4 can also be designed on-site according to different needs. In the actual measurement process, the radiative heat probe is placed in the vacuum chamber, and the tail end of the thermocouple is connected to the measuring wire and then to the temperature acquisition card. The particles diffusing in the plasma fall onto the copper sheet. The heat flux density at a certain radial position of the detection element can be determined using the following formula. Considering the axial symmetry of the vacuum chamber, the heat flux density distribution on the vacuum wall is determined by axial integration.

[0030]

[0031] Where m is the mass of the copper plate, and C p Δt is the specific heat capacity of copper, A is the surface area of ​​the copper plate, Δt is the plasma discharge time, and ΔT is the temperature rise before and after the thermocouple measurement.

[0032] This invention solves the problem that thermocouples cannot directly measure the temperature of heat flux density. By utilizing the thermal conductivity of copper sheets and the temperature measurement of thermocouples, and employing an array distribution, the radial radiation heat flux density that is emitted from the plasma due to ion diffusion towards the vacuum wall is indirectly measured.

[0033] The specific embodiments described above provide a further detailed explanation of the technical solution of the present invention. Any modifications or substitutions made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An array-type radiative thermal probe for measuring plasma radiative heat flux density, characterized in that, It includes a detection element (1), a thermocouple (2), a mounting base (3), a fixing base (4), and a fixing clip; The detection element (1) has two threaded holes and is fixed to the mounting base (3) by threads; The mounting base (3) has a through hole along the thickness direction and is connected to the fixing base (4) by a thread; The fixing buckle is welded to the fixing base (4); The thermocouple (2) passes through the through hole of the mounting base (3) and the fixing base (4), and is fixed to the fixing base (4) by a fixing buckle; The mounting base (3) is a ceramic material with a length of 120 mm, a width of 20 mm, and a thickness of 10 mm; the diameter of the through hole of the mounting base (3) through the thermocouple (2) is 1.1 mm; the diameter of the threaded hole of the mounting base (3) for fixing the detection element (1) is 1 mm and the depth is 5 mm; the diameter of the through hole between the mounting base (3) and the fixing base (4) is 2 mm. The fixing buckle includes a hollow cylinder one (6) with an inner diameter of 3 mm, an outer diameter of 3.4 mm, and a depth of 15 mm, and a hollow cylinder two (5) with an inner diameter of 5 mm and an outer diameter of 10 mm; the hollow cylinder one (6) and the hollow cylinder two (5) are connected by a structure with an inner diameter of 3 mm, an outer diameter of 5 mm, a chamfered conical platform in the middle, and external threads on the outside; the hollow cylinder two (5) has internal threads inside.

2. An array-type radiative thermal probe for measuring plasma radiative heat flux density according to claim 1, characterized in that: The detection element (1) is a copper plate with a diameter of 10 mm and a thickness of 0.4 mm; the detection element (1) has through holes of 1 mm at both ends of its diameter.

3. An array-type radiative thermal probe for measuring plasma radiative heat flux density according to claim 1, characterized in that: The thermocouple (2) has a K-type graduation and a measuring head diameter of 1 mm.

4. An array-type radiative thermal probe for measuring plasma radiative heat flux density according to claim 1, characterized in that: The fixing base (4) is made of 304 stainless steel with a length of 120 mm, a width of 20 mm, and a thickness of 10 mm; the diameter of the through hole in the fixing base (4) is 1.1 mm.

5. An array-type radiative thermal probe for measuring plasma radiative heat flux density according to claim 1, characterized in that: The fixing buckle is made of 304 stainless steel.

6. An array-type radiative thermal probe for measuring plasma radiative heat flux density according to claim 1, characterized in that: The bottom of the fixing buckle has a cube structure with a diagonal length of 10 mm and a thickness of 1 mm. The opening in the middle of the cube structure is circular with a diameter of 1.1 mm.

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