A novel atomic layer thermopile thermal flux sensor based on metal thin strip and its packaging process

Abstract

The present invention discloses a novel atomic layer thermopile heat flow sensor with a metal strip as a substrate and its packaging process, comprising: a packaging sleeve, a metal substrate is fixedly provided inside the packaging sleeve, a sensitive element with a metal strip as a film substrate is fixedly provided on the surface of the metal substrate, wire grooves are provided on both sides of the metal substrate, and silver wires are fixedly provided in the wire grooves; the structure of the sensitive element comprises: a metal strip with a transition film layer deposited on the top; a thermoelectric effect film deposited on the top of the transition film layer; a conductive film deposited on both ends of the thermoelectric effect film; and transition slopes are provided on both sides of the metal substrate. The present invention utilizes the good thermal conductivity and high heat capacity of metal so that the sensor can conduct heat away in time during long-term use, ensuring that the temperature of the sensor is within a controlled range; utilizing the good flexibility of the metal strip, the electrical conduction node between the conductive film and the silver wire is arranged on the side of the metal substrate, reducing the influence of the intrusive sensor on the local flow field.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat flux sensors, and more specifically, relates to a novel atomic layer thermopile heat flux sensor with a metal thin strip as a substrate and a packaging process thereof. Background Art

[0002] Boundary layer transition is one of the few basic scientific problems left over from classical mechanics, and together with the turbulence problem, it is called the "problem of the century". For hypersonic flight, after the hypersonic boundary layer changes from laminar flow to turbulent flow, the wall heat flux and friction will increase sharply. Therefore, theoretical and experimental research on hypersonic boundary layer transition is an important means to understand the transition mechanism and further control the transition. Combined with the understanding of current theoretical research on hypersonic boundary layer transition, the evolution and development of incoming flow disturbances are considered to be the core of the boundary layer transition mechanism. Correspondingly, wind tunnel experimental research has also paid more and more attention to the testing and analysis of high-frequency pulsating heat flux. Conventional hypersonic wind tunnels have low heat flux, but the test time is long and the temperature accumulation effect is obvious; flight tests are carried out in a real and complete aerodynamic environment, with long test time and high heat flux, and the demand for high-frequency pulsating heat flux testing is very urgent. At present, high-frequency pulsating heat flux testing mainly relies on atomic layer thermopile heat flux sensors. However, the sensitive element of the atomic layer thermopile heat flow sensor is mainly based on strontium titanate thin film as the carrier of the thermoelectric effect film. The strontium titanate thin film has poor thermal conductivity and small heat capacity, which makes the atomic layer thermopile heat flow sensor unsuitable for long-term high-frequency pulsating heat flow testing, even if the heat flow in the test environment is not high; the strontium titanate thin film is difficult to process and is easily damaged, resulting in the sensor directly brushing conductive silver paste on the sensor surface to form electrical conduction between the conductive film and the silver wire when transmitting the electrical signal sensed by the thermoelectric effect film, causing unevenness in the small area around the lead hole on the sensor surface, which will cause local flow field interference. In addition, when using water-cooled insulation sleeves and other methods to achieve sensor temperature control, it is inevitable to greatly increase the size of the sensor, which will greatly increase the local flow field interference caused by the sensor for such invasive heat flow testing methods. Therefore, the new metal-based atomic layer thermopile heat flow sensor will use the good thermal conductivity of metal to conduct heat away in time and the large heat capacity of the metal matrix, so that the sensitive element is always in a lower temperature range; at the same time, the good flexibility of the metal strip allows the contact point between the conductive film and the silver wire to be arranged on the side, and the sensor sensing surface has no surface unevenness caused by the application of conductive glue. The new atomic layer thermopile heat flow sensor thus formed has a flat sensing surface, which can meet the needs of long-term high-frequency pulsating heat flow testing in conventional hypersonic wind tunnels and flight tests. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0004] In order to achieve these purposes and other advantages according to the present invention, a novel atomic layer thermopile heat flow sensor based on a metal strip is provided, comprising:

[0005] The packaging sleeve has a metal base inside which is fixedly mounted, a sensitive element with a metal strip as a film substrate is fixedly mounted on the surface of the metal base, and wire grooves are arranged on both sides of the metal base, in which silver wires are fixedly mounted;

[0006] The structure of the sensitive element includes:

[0007] A metal thin strip, on which a transition film layer is deposited; a thermoelectric effect film, which is deposited on the transition film layer; and a conductive film, which is deposited on both ends of the thermoelectric effect film;

[0008] Transition slopes are arranged on both sides of the metal substrate, and the conductive film deposited on the sensitive element extends along the transition slopes into the wire groove, and the conductive film of the sensitive element is electrically connected with the silver wire.

[0009] Preferably, the metal strip is fixed to the surface of the metal substrate by means of high temperature conductive adhesive.

[0010] Preferably, a positioning threaded hole is provided on the side of the metal substrate, and a through hole matched with the positioning threaded hole is provided on the packaging sleeve, and the positioning and fixing of the packaging sleeve and the metal substrate are achieved by arranging top screws in the through hole and the positioning threaded hole.

[0011] Preferably, the upper end surface of the metal substrate is provided with a transition fillet.

[0012] Preferably, the wire groove is filled with high temperature glue, and the silver wire is fixed in the wire groove by the high temperature glue; the silver wire and the conductive film are electrically connected by brushing high temperature silver paste.

[0013] Preferably, the packaging sleeve may be one of a silicon nitride ceramic packaging sleeve, an alumina ceramic packaging sleeve or a silicon nitride ceramic packaging sleeve.

[0014] Preferably, the thermoelectric effect film may be a yttrium barium copper oxide film or a lanthanum manganese copper oxide film.

[0015] Preferably, the packaging process of the novel atomic layer thermopile heat flow sensor based on the metal strip of the present invention comprises the following steps:

[0016] Step 1: polishing the surface of the metal strip; then depositing a transition film layer on the surface of the metal strip, depositing a thermoelectric effect film on the surface of the transition film layer, and depositing a conductive film on both ends of the thermoelectric effect film; processing a transition fillet on the metal substrate;

[0017] Step 2: Apply high-temperature conductive glue on the lower surface of the sensitive element, overlap the arc part of the sensitive element with the arc part of the metal substrate, and attach the sensitive element to the metal substrate;

[0018] Step 3: Use welding or high-temperature conductive adhesive to ensure good electrical conduction between the silver wire and the conductive film; then pour high-temperature adhesive into the wire groove, and the high-temperature adhesive is cured to fix the silver wire in the wire groove;

[0019] Step 4: Cover the metal substrate with a packaging sleeve, and ensure that the through hole of the packaging sleeve is aligned with the positioning threaded hole of the metal substrate, and install top screws in the through hole and the positioning threaded hole to achieve positioning and fixation between the packaging sleeve and the metal substrate.

[0020] Preferably, the deposition technology of the transition film layer may be an ion beam assisted deposition technology or an inclined substrate deposition technology.

[0021] The present invention includes at least the following beneficial effects: The present invention provides a new type of metal-based atomic layer thermopile heat flow sensor, which can be used for long-term high-frequency pulsating heat flow testing in conventional hypersonic wind tunnels, flight tests and other test environments, and its beneficial results are: the metal-based atomic layer thermopile heat flow sensor utilizes the good thermal conductivity and high heat capacity of metal, so that the sensor can conduct heat out in time during long-term use, ensuring that the sensor temperature is within a controlled range; using metal thin strips as the substrate of thermoelectric effect thin films and conductive films, and utilizing the good flexibility of the metal thin strips, the electrical conduction nodes between the conductive film and the silver wire are arranged on the side of the metal substrate, and the sensor sensing surface is flat, reducing the impact of the invasive sensor on the local flow field.

[0022] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the structure of a novel atomic layer thermopile heat flow sensor based on a metal strip provided by the present invention;

[0024] Figure 2 A schematic diagram of the structure of a sensitive element provided by the present invention;

[0025] Figure 3 for Figure 1 Section view at AA in the middle. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0027] It should be understood that terms such as “having”, “including” and “comprising” used herein do not specify the existence or addition of one or more other elements or combinations thereof.

[0028] like Figure 1-3 As shown: A novel atomic layer thermopile heat flow sensor based on a metal strip of the present invention comprises:

[0029] The packaging sleeve 1 has a metal base 3 fixedly mounted inside it, a sensitive element 6 with a metal strip 11 as a film substrate fixedly mounted on the surface of the metal base 3, and wire grooves 5 are arranged on both sides of the metal base 1, and silver wires 2 are fixedly mounted in the wire grooves 5;

[0030] The structure of the sensing element 6 includes:

[0031] A metal thin strip, on which a transition film layer 8 is deposited; a thermoelectric effect film 9, which is deposited on the transition film layer 8; and a conductive film 10, which is deposited on both ends of the thermoelectric effect film 9;

[0032] Transition slopes 12 are provided on both sides of the metal substrate 3 , and the conductive film 10 deposited on the sensitive element 6 extends partially along the transition slopes 12 into the wire groove 5 , and the conductive film 10 of the sensitive element 6 is electrically connected to the silver wire 2 .

[0033] Working principle: This atomic layer thermopile heat flow sensor is used to extract the electrical signals directly related to the high-frequency heat flow test from the shock wind tunnel and the conventional hypersonic wind tunnel; when there is a temperature gradient on the upper and lower surfaces of the thermoelectric effect film 9, due to the transverse Seebeck effect, a thermoelectric potential is generated transversely and perpendicular to the temperature gradient direction of the upper and lower surfaces of the thermoelectric effect film 9; the silver wire 2 is connected to the conductive film 10, and the test signal is extracted from the shock wind tunnel and the conventional hypersonic wind tunnel, and the high-frequency pulsating heat flow can be directly obtained; the purpose of depositing the transition film layer 8 is to ensure the oriented growth of the thermoelectric effect film 9, the electrical insulation between the thermoelectric effect film 9 and the metal strip 11, and to prevent the metal atoms of the block metal strip 11 from diffusing into the thermoelectric effect film 9. The setting of the transition slope 12 is to ensure that the silver wire does not protrude from the side of the metal substrate and forms a good electrical conduction with the conductive film 10. Since the atomic layer thermopile heat flow sensor uses a metal strip 11 as the base of the sensitive element 6, the good thermal conductivity and high heat capacity of the metal are utilized, so that the sensor can conduct heat away in time during long-term use, ensuring that the sensor temperature is within the controlled range; the metal strip 11 is used as the base of the thermoelectric effect film 9 and the conductive film 10, and the good flexibility of the metal strip 11 is utilized, so that the electrical conduction node between the conductive film 10 and the silver wire 2 is arranged on the side of the metal substrate 3, and the sensor sensing surface is flat, reducing the impact of the intrusive sensor on the local flow field. The new atomic layer thermopile heat flow sensor obtained in this way needs to be statically calibrated to obtain its sensitivity coefficient, and its dynamic response time and other parameters can be dynamically calibrated using pulse-type experimental equipment such as shock tubes.

[0034] In the above technical solution, the metal strip 11 is fixed to the surface of the metal substrate 3 by means of high temperature conductive adhesive, and the high temperature conductive adhesive can form good heat conduction and fixation between the metal substrate 3 and the sensitive element 6 .

[0035] In the above technical solution, a positioning threaded hole 4 is provided on the side of the metal substrate 3, and a through hole matched with the positioning threaded hole is provided on the packaging sleeve. By setting a top screw in the through hole and the positioning threaded hole 4, the packaging sleeve 1 and the metal substrate 3 are positioned and fixed.

[0036] In the above technical solution, the upper end surface of the metal substrate 3 is provided with a transition fillet 7, and the transition fillet 7 is provided to ensure that the conductive film of the sensitive element 6 can be well transitioned from the upper surface of the metal substrate 3 to the side surface of the metal substrate 3.

[0037] In the above technical solution, the wire groove 5 is filled with high temperature glue, and the silver wire 2 is fixed in the wire groove 5 by the high temperature glue; the silver wire 2 and the conductive film 10 are electrically connected by brushing high temperature silver paste.

[0038] In the above technical solution, the packaging sleeve 1 can be one of a silicon nitride ceramic packaging sleeve, an alumina ceramic packaging sleeve or a silicon nitride ceramic packaging sleeve.

[0039] In the above technical solution, the thermoelectric effect film 9 can be a yttrium barium copper oxide film or a lanthanum manganese copper oxide film.

[0040] In the above technical solution, the packaging process of the novel atomic layer thermopile heat flow sensor with metal thin strip as the substrate of the present invention comprises the following steps:

[0041] Step 1: polish the surface of the metal strip 11; then deposit a transition film layer 8 on the surface of the metal strip 11, deposit a thermoelectric effect film 9 on the surface of the transition film layer 8, and deposit a conductive film 10 on both ends of the thermoelectric effect film 9; process a transition fillet on the metal substrate 3;

[0042] Step 2: Apply high-temperature conductive glue on the lower surface of the sensitive element 6, overlap the arc part of the sensitive element 6 with the arc part of the metal substrate 3, and attach the sensitive element 6 to the metal substrate;

[0043] Step 3: Use welding or high-temperature conductive adhesive to ensure good electrical conduction between the silver wire 2 and the conductive film 10; then pour the high-temperature adhesive into the wire groove 5, and the high-temperature adhesive is cured to fix the silver wire 10 in the wire groove 5;

[0044] Step 4: Cover the metal base 3 with the packaging sleeve 1, and ensure that the through hole of the packaging sleeve 1 is aligned with the positioning threaded hole 4 of the metal base 3, and install the top screw in the through hole and the positioning threaded hole 4 to achieve positioning and fixation between the packaging sleeve 1 and the metal base 3.

[0045] In step 1, the surface of the metal strip 11 is polished to ensure good bonding between the transition film layer 8 and the metal strip 11 .

[0046] Preferably, the deposition technology of the transition film layer 8 may be an ion beam assisted deposition technology or an inclined substrate deposition technology.

[0047] The number of devices and processing scales described here are used to simplify the description of the present invention. Applications, modifications and variations of the present invention will be obvious to those skilled in the art.

[0048] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A novel atomic layer thermopile heat flow sensor based on a metal strip, characterized in that: include: The packaging sleeve has a metal base inside which is fixedly mounted, a sensitive element with a metal strip as a film substrate is fixedly mounted on the surface of the metal base, and wire grooves are arranged on both sides of the metal base, in which silver wires are fixedly mounted; The structure of the sensitive element includes: A metal thin strip, on which a transition film layer is deposited; a thermoelectric effect film, which is deposited on the transition film layer; and a conductive film, which is deposited on both ends of the thermoelectric effect film; Transition slopes are arranged on both sides of the metal substrate, and the conductive film deposited on the sensitive element extends along the transition slopes into the wire groove, and the conductive film of the sensitive element is electrically connected to the silver wire; The packaging process of the new atomic layer thermopile heat flow sensor includes the following steps: Step 1: polishing the surface of the metal strip; then depositing a transition film layer on the surface of the metal strip, depositing a thermoelectric effect film on the surface of the transition film layer, and depositing a conductive film on both ends of the thermoelectric effect film; processing a transition fillet on the metal substrate; Step 2: Apply high-temperature conductive glue on the lower surface of the sensitive element, overlap the arc part of the sensitive element with the arc part of the metal substrate, and attach the sensitive element to the metal substrate; Step 3: Use welding or high-temperature conductive adhesive to ensure good electrical conduction between the silver wire and the conductive film; then pour high-temperature adhesive into the wire groove, and the high-temperature adhesive is cured to fix the silver wire in the wire groove; Step 4: Cover the metal substrate with a packaging sleeve, and ensure that the through hole of the packaging sleeve is aligned with the positioning threaded hole of the metal substrate, and install top screws in the through hole and the positioning threaded hole to achieve positioning and fixation between the packaging sleeve and the metal substrate.

2. The novel atomic layer thermopile heat flow sensor based on a metal thin strip as claimed in claim 1 is characterized in that: The metal strip is fixed on the surface of the metal substrate by means of high temperature conductive adhesive.

3. The novel atomic layer thermopile heat flow sensor based on a metal thin strip as claimed in claim 1, characterized in that: The side of the metal substrate is provided with a positioning threaded hole, and the packaging sleeve is provided with a through hole matched with the positioning threaded hole. The positioning and fixing of the packaging sleeve and the metal substrate are achieved by arranging top screws in the through hole and the positioning threaded hole.

4. The novel atomic layer thermopile heat flow sensor based on a metal thin strip as claimed in claim 1, characterized in that: The upper end surface of the metal substrate is provided with a transition fillet.

5. The novel atomic layer thermopile heat flow sensor with a metal strip as a substrate as claimed in claim 1, wherein the wire groove is filled with high-temperature glue, and the silver wire is fixed in the wire groove by the high-temperature glue; the silver wire and the conductive film are electrically connected by brushing high-temperature silver paste.

6. The novel atomic layer thermopile heat flow sensor based on a metal thin strip as claimed in claim 1, characterized in that: The packaging sleeve is one of a silicon nitride ceramic packaging sleeve, an alumina ceramic packaging sleeve or a silicon nitride ceramic packaging sleeve.

7. The novel atomic layer thermopile heat flow sensor based on a metal strip as claimed in claim 1, characterized in that: The thermoelectric effect film is a yttrium barium copper oxide film or a lanthanum manganese copper oxide film.

8. The novel atomic layer thermopile heat flow sensor based on a metal thin strip as claimed in claim 1, characterized in that: The deposition technology of the transition film layer is ion beam assisted deposition technology or inclined substrate deposition technology.

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