A cylindrical platinum film heat flux sensor for a hypersonic shock tunnel

Abstract

This invention discloses a cylindrical platinum film heat flux sensor for hypersonic shock tunnels, comprising: a glass column serving as a carrier substrate for the heat flux sensor; wherein a platinum resistance film is disposed on a diameter of one end of the glass column, and silver paste contacts are disposed at both ends of the platinum resistance film, and the silver paste contacts are electrically connected to the platinum film within the platinum resistance film. The sensor model designed using this invention reduces the impact of sensor installation on the geometric parameters of the original model, thereby reducing the measurement result deviation compared to existing dimensional sensors.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of platinum film heat flow sensor, and particularly relates to a cylindrical platinum film heat flow sensor for a hypersonic shock tunnel. BACKGROUND

[0002] The measurement technology based on thin film resistance heat flow sensor is an important method for measuring the aerodynamic heat environment in a shock tunnel. In the past few decades, the technology has been continuously developed and innovated. On the one hand, in order to obtain more data per unit area, integration has become a trend in the development of sensor technology. On the other hand, in order to reduce the measurement error caused by the installation of the sensor, miniaturization of the sensor has been continuously innovated as a research direction. From the earliest 5mm in diameter to 2mm in diameter, great progress has been made in both the heat-sensitive element technology and the silver paste drawing technology. In particular, the 2mm-diameter cylindrical glass substrate manufacturing technology has matured in recent years. However, due to the existing technical problems, the platinum resistance has a small resistance value, and the measurement accuracy is insufficient. SUMMARY

[0003] The present application relates to the technical field of platinum film heat flow sensor, and particularly relates to a cylindrical platinum film heat flow sensor for a hypersonic shock tunnel.

[0004] To solve the above technical problems, the present application specifically provides the following technical solutions:

[0005] A cylindrical platinum film heat flow sensor for a hypersonic shock tunnel has the following features:

[0006] A glass column is used as a bearing substrate for the heat flow sensor.

[0007] The end of the glass column is provided with a platinum resistance film at a certain diameter, and both ends of the platinum resistance film are provided with silver paste contacts, and the silver paste contacts are electrically connected to the platinum film in the platinum resistance film.

[0008] As a preferred scheme of the present application, the thickness of the platinum film in the platinum resistance film ranges from 10 to 100nm.

[0009] As a preferred scheme of the present application, the silver paste contacts are connected to a silver paste wire, and the silver paste wire is arranged on the surface of the glass column.

[0010] As a preferred scheme of the present application, a through hole is formed in the interior of the glass column along the axial direction of the glass column, and the platinum resistance film is arranged at a certain diameter of the longitudinal section of the through hole close to the end of the glass column.

[0011] As a preferred scheme of the present application, a plurality of platinum resistance thin films are arranged in the through hole; and two independent silver paste lines are arranged on the surface of the glass column.

[0012] One end of the platinum film in each of the plurality of platinum resistance thin films is electrically connected to one of the two silver paste lines, and the other end of the platinum film in each of the plurality of platinum resistance thin films is electrically connected to the other silver paste line.

[0013] As a preferred scheme of the present application, the plurality of platinum resistance thin films are arranged at equal intervals on the same longitudinal section of the glass column.

[0014] Alternatively, the plurality of platinum resistance thin films are distributed on different longitudinal sections of the glass column.

[0015] As a preferred scheme of the present application, a groove for arranging the silver paste lines is arranged on the surface of the glass column.

[0016] As a preferred scheme of the present application, the glass column comprises an upper column body and a lower column body, and the upper column body and the lower column body are mirror-symmetric.

[0017] The platinum resistance thin film comprises an upper half film body and a lower half film body, two ends of the upper half film body are fixedly connected to the inner side surface of the upper column body, and the lower half film body is fixedly arranged on the inner side surface of the lower column body.

[0018] The connection part of the upper column body and the lower column body forms the groove.

[0019] As a preferred scheme of the present application, both sides of the upper column body and the lower column body are provided with an inner groove along the length direction.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The sensor model designed in the present application can make the influence of the installation of the sensor on the geometric parameters of the original model relatively small, so that the measurement result deviation is smaller than the error of the existing size sensor, and the combination of the silver paste contact and the platinum film is used to improve the high conductivity of the electrical connection of the sensor. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0023] Figure 1 A schematic diagram of the sensor structure is provided for embodiments of the present invention;

[0024] Figure 2 A schematic diagram of the installation of a glass column with a through hole and a single platinum film base is provided for an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of an installation structure for multiple platinum film bases and glass columns, provided in an embodiment of the present invention.

[0026] Figure 4 This invention provides another schematic diagram of the structure for mounting multiple platinum film bases and glass columns;

[0027] Figure 5 Provided for embodiments of the present invention Figure 4 A schematic diagram of the enlarged structure of part A in the middle.

[0028] The labels in the diagram represent the following:

[0029] 1-Glass pillar; 2-Platinum resistance film; 3-Silver paste contact; 4-Silver paste line; 5-Through hole; 6-Groove; 7-Inner groove; 101-Upper cylindrical body; 102-Lower cylindrical body; 201-Upper half film; 202-Lower half film. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] like Figure 1 As shown, the present invention provides a cylindrical platinum film heat flux sensor for hypersonic shock tunnels, comprising:

[0032] Glass column 1 is used as the support substrate for the heat flow sensor;

[0033] Among them, a platinum resistance film 2 is provided on a certain diameter of the end of the glass column 1, and silver paste contacts 3 are provided at both ends of the platinum resistance film 2, and the silver paste contacts 3 are electrically connected to the platinum film inside the platinum resistance film 2.

[0034] The thickness of the platinum film in the platinum resistance film 2 ranges from 10 to 100 nm. It can be obtained by vacuum evaporation sputtering, vacuum magnetron sputtering, or by coating with platinum paste and baking. Platinum metal changes linearly with temperature. Because the platinum film is relatively thin, the sensor is more sensitive to temperature response, which is why the platinum thin film resistance thermometer has the characteristic of high frequency response.

[0035] The silver paste contact 3 is connected with a silver paste line 4, and the silver paste line 4 is arranged on the surface of the glass column 1. Taking a φ2 (2mm in diameter) platinum thin film resistance heat flow sensor as an example, there are four parts, a glass column (as a base bearing a platinum film and a silver paste line), a platinum film (an end surface of the glass column), two silver paste lines (glass column bus bars, connecting two ends of the platinum film), and a tail wire, as shown in the figure. Figure 1 The platinum thin film resistance heat flow sensor is finally formed into a qualified product after plating, sintering, drawing a silver paste line, sintering, welding a wire, calibration, and aging.

[0036] The platinum thin film resistance heat flow sensor is applied to shock tunnel heat measurement, and the time of the shock tunnel is generally only a few milliseconds to tens of milliseconds. When measuring heat, the sensor needs to have a high frequency response. The response time of the platinum resistance sensor on the market cannot meet the requirement of high frequency response. Therefore, the platinum thin film resistance heat flow sensor with high frequency response has a sensor frequency response of 1MHz, and can meet the requirement of shock tunnel (test time 5-30ms) heat measurement.

[0037] In the manufacturing process of the sensor, 10-100nm of a thin film is deposited on a φ2 glass column base by vacuum evaporation sputtering, and then placed in a high temperature furnace. After the temperature reaches the softening temperature of the glass base, the platinum film and the glass base are combined tightly through multiple sintering.

[0038] After the platinum film is developed, a silver paste with very small resistance is brushed on both ends of the platinum film, and then placed in a high temperature furnace for multiple sintering, so that the silver paste and the glass base are firmly combined to form a silver paste contact. The silver paste contact is used for the welding point of the connecting wire of the sensor.

[0039] The softening temperature of the glass column is generally 500-550℃, and the temperature in the high temperature furnace is generally set at the softening temperature of the glass. The softening temperature of the glass is adjusted according to the softening temperature of the glass.

[0040] After the platinum film is plated and the silver paste is dotted, the platinum film and the silver paste float on the surface of the glass base. If the heat treatment sintering is not performed, the platinum film and the silver paste cannot be directly used and are very easy to be damaged. Therefore, the platinum film and the silver paste are placed in the high temperature furnace for multiple sintering, so that a part of the platinum film and the silver paste penetrate into the glass base (the part of the platinum film and the glass column end combined forms a platinum resistance thin film, and the part of the silver paste and the glass combined forms a silver paste contact), so as to become a whole, so as to improve the combination degree of the platinum film, the silver paste and the end of the glass column.

[0041] After the glass substrate is plated with platinum film, it is placed in a high-temperature furnace (at the glass softening temperature) and heated for 1 hour, and then naturally cooled. The resistance of the platinum film at both ends is measured. During this process, when the glass softens, part of the platinum penetrates into the glass substrate, thereby improving the bonding degree of the platinum film and the glass, and improving the stability and service life of the platinum film. Then draw silver paste (as the lead wire of the platinum film) on both ends of the platinum film, place it in a high-temperature furnace (at the glass softening temperature), heat for 1 hour, and then naturally cool. The resistance of the platinum film at both ends is measured. During this process, when the glass softens, part of the silver paste penetrates into the glass, thereby improving the bonding degree of the silver paste and the glass. At this time, the silver paste is relatively thin and is prone to breakage during use. Then draw silver paste again on the basis of the original silver paste and sinter. The purpose is still to improve the bonding degree of the silver paste and the glass and to thicken the silver paste layer to facilitate subsequent welding of the lead wire at the tail of the sensor.

[0042] The purpose of multiple sintering is to improve the bonding degree of the platinum film, silver paste wire and glass. The first sintering aims to improve the bonding degree of the platinum film and the glass substrate. Then draw silver paste on both ends of the platinum film and the glass column, and perform the second sintering to improve the bonding of the silver paste and the glass. Then draw silver paste again on the basis of the original silver paste, which aims to make the silver paste firm and improve the stability of the product. If necessary, the third sintering can be performed. After sintering, the lead wire is welded at the tail of the silver paste contact.

[0043] The basic principle of platinum thin film resistance thermometer temperature measurement is that when the temperature increases, the kinetic energy of free electrons increases, which changes the movement mode of free electrons, increases the energy required for directional movement, which is reflected in the resistance, and the resistance value will increase. This relationship can be described as:

[0044] Rt = R0(1 + αt),

[0045] Where Rt: resistance value at temperature t, R0: resistance value at zero degrees Celsius, α: temperature coefficient of thermal resistance (1 / ℃), indicating the relative change of resistance value caused by unit temperature.

[0046] Therefore, based on the basic principle of platinum thin film resistance thermometer temperature measurement, in the activated shock wave generation state of the wind tunnel, to improve the frequency response of the sensor, a single platinum film is in an ideal temperature sensor, that is, the accuracy of the temperature sensor is affected by the forming quality of the single platinum film. In actual situations, the actual resistance of the parallel same resistance does not have a specific change, but in the forming process, it is impossible to ensure that the resistance of multiple platinum films remains completely consistent, and there is a small difference. Therefore, the difference can be used to improve the sensing accuracy by connecting multiple platinum films in parallel. In the above formula,

[0047]

[0048] The improvement of the detection accuracy of the specific sensor is reflected in the structure, as shown in Figure 2 To this end, the application further provides an embodiment of the glass column 1 for concentrating the shock wave temperature in the shock wave wind tunnel contacted by the sensor. The inside of the glass column 1 is formed with a through hole 5 along the axial direction of the glass column 1, that is, the shock wave temperature in the shock wave wind tunnel experiment passes through the through hole 5, and at this time, the platinum resistance film 2 is arranged on a certain diameter of the longitudinal section of the through hole 5 close to the end of the glass column 1. Then, in the preparation process, the glass column 1 can be pre-prepared in a hollow tubular structure, and a planar glass sheet (the width is equal to the diameter of the glass column 1) is inserted into the through hole 1 along the axial direction of the through hole 1. Therefore, the glass sheet (that is, the substrate of the platinum resistance film 2) and the inner wall of the glass column 1 are sintered by directional soft sintering, and the platinum film is constructed on the end (the width direction side) of the glass sheet by sputtering. The silver paste line 4 can be pre-drawn on the side (length direction side) of the glass sheet.

[0049] In this way, by the directional sintering method (along the axial direction of the through hole 1), the glass column 1 is placed in the sintering furnace for sintering, that is, the whole glass substrate does not need to be softened too much, and the deformation and breakpoint of the silver paste line 4 caused by the softening of the glass column 1 in the sintering process are avoided.

[0050] Of course, the application can also perform equidistant strip platinum film sputtering on the upper surface or the lower surface of the glass sheet (at this time, the glass sheet is a whole piece, and the length can be equal to that of the glass column 1).

[0051] In this process, to further improve the accuracy of the sensor, a plurality of platinum resistance films 2 are arranged in the through hole 5; and two independent silver paste lines 4 are arranged on the surface of the glass column 1, wherein the surface of the glass column 1 refers to the inner surface where the through hole is located.

[0052] As shown in Figure 3 and Figure 4 , wherein one end of the platinum film in the plurality of platinum resistance films 2 is electrically connected to one of the two silver paste lines 4, and the other end of the platinum film in the plurality of platinum resistance films 2 is electrically connected to the other silver paste line 4.

[0053] As shown in Figure 3 , the plurality of platinum resistance films 2 are arranged equidistantly on the same longitudinal section of the glass column 1, or as shown in Figure 4 , the plurality of platinum resistance films 2 are distributed on different longitudinal sections of the glass column 1.

[0054] Further, in order to further improve the sintering and body fusion effect of the silver paste line 4 and the glass column 1, a groove 6 for arranging the silver paste line 4 is arranged on the surface of the glass column 1, that is, the groove 6 is arranged on the busbar of the glass column 1 in advance, and then the silver paste line 4 is arranged in the groove 6, and in the sintering process, the part of the groove 6 is heated and sintered.

[0055] In the present application, in order to explain in detail the forming method of the glass column 1 as the carrier of the silver paste line and the platinum film, the glass column 1 is specifically divided into an upper column body 101 and a lower column body 102, the upper column body 101 and the lower column body 102 are mirror-symmetric, and a cylindrical tube body (that is, the glass column 1) is formed by sintering connection of the upper column body 101 and the lower column body 102. In this sintering process, the glass column 1 as a whole is placed in the sintering furnace for sintering, and can be sintered by directional high-temperature gas flow.

[0056] As shown in Figure 4 Similarly, the platinum resistance film 2 includes an upper half film body 201 and a lower half film body 202, the two ends of the upper half film body 201 are fixedly connected to the inner side surface of the upper column body 101, and the lower half film body 202 is fixedly arranged on the inner side surface of the lower column body 102. Since the diameter of the glass column 1 is φ2 (2mm).

[0057] In the structure shown in Figure 3 The platinum film body 2 does not need to be divided into the upper half film body 201 and the lower half film body 202.

[0058] But the connecting surface of the separated upper column body 101 and the lower column body 102 is connected first when melting, and only the connecting part needs to reach the connection state, because at this time, whether it is a platinum film or a silver paste line 4, it can realize a good melting connection state with the glass column 1.

[0059] Among them, the connecting part of the upper column body 101 and the lower column body 102 forms a groove 6 (that is, the edge of the half column body 101), and the groove 6 provides a good sintering attachment point.

[0060] As shown in Figure 5As shown, in order to realize good sintering of the groove 6 and the silver paste line 4, the two side edges of the upper and lower prisms 101 and 102 are provided with lengthwise inner grooves 7, so that in the sintering process, symmetric interference air flows (that is, on both sides of the groove 6) along the tangential direction of the glass column 1 (that is, the tangential direction of the glass column 1 at the position of the groove 6) are applied to artificially control the sintering state of the groove 6, so that the glass column 1 at the groove 6 wraps the silver paste line 4, and the inner groove 7 can reduce the flow rate of the interference air flow on both sides of the groove 6 and enhance the directional wrapping of the edge of the glass column 1 to the silver paste line 4 in the groove 6, so as to realize stable electrical conduction, avoid the traditional glass substrate from softening and flowing in the sintering process, and make the silver paste line 4 drawn on the glass substrate have breakpoints, thereby improving the yield of the sensor in preparation.

[0061] The above examples are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and such modifications or equivalent replacements shall also be considered to fall within the protection scope of the present application.

Claims

1. A cylindrical platinum film heat flux sensor for a hypersonic shock tunnel, characterized in that Possessing: A glass column (1) is used as a heat flow sensor carrier substrate; The end of the glass column (1) is provided with a platinum resistance film (2) on a certain diameter, both ends of the platinum resistance film (2) are provided with silver paste contacts (3), and the silver paste contacts (3) are electrically connected with the platinum film in the platinum resistance film; The inside of the glass column (1) is formed with a through hole (5) along the axial direction of the glass column (1), and the platinum resistance film (2) is arranged on a certain diameter of the longitudinal section of the through hole (5) close to the end of the glass column (1); A plurality of platinum resistance films (2) are arranged in the through hole (5); The surface of the glass column (1) is provided with two independent silver paste lines (4); Wherein, one end of the platinum film in the plurality of platinum resistance films (2) is electrically connected with one of the two silver paste lines (4), and the other end of the platinum film in the plurality of platinum resistance films (2) is electrically connected with the other silver paste line (4); A plurality of platinum resistance films (2) are arranged at equal intervals on the same longitudinal section of the glass column (1); Or, a plurality of platinum resistance films (2) are distributed on different longitudinal sections of the glass column (1).

2. A cylindrical platinum film heat flux sensor for a hypersonic shock tunnel according to claim 1, characterized in that The thickness of the platinum film in the platinum resistance film (2) ranges from 10 to 100 nm.

3. A cylindrical platinum film heat flux sensor for a hypersonic shock tunnel according to claim 1, characterized in that The silver paste contact (3) is connected with a silver paste line (4), and the silver paste line (4) is arranged on the surface of the glass column (1).

4. A cylindrical platinum film heat flux sensor for a hypersonic shock tunnel according to claim 1, characterized in that The surface of the glass column (1) is provided with a groove (6) for arranging the silver paste line (4).

5. A cylindrical platinum film heat flux sensor for a hypersonic shock tunnel according to claim 4, characterized in that The glass column (1) comprises an upper column body (101) and a lower column body (102), and the upper column body (101) and the lower column body (102) are mirror-symmetric; The platinum resistance film (2) comprises an upper half film body (201) and a lower half film body (202), both ends of the upper half film body (201) are fixedly connected to the inner side surface of the upper column body (101), and the lower half film body (202) is fixedly arranged on the inner side surface of the lower column body (102); Wherein, the connection part of the upper column body (101) and the lower column body (102) forms the groove (6).

6. A cylindrical platinum film heat flux sensor for a hypersonic shock tunnel according to claim 5, characterized in that Both sides of the upper column body (101) and the lower column body (102) are provided with an inner groove (7) along the length direction.

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