Impingement heat exchange based nozzle structure and device for cooling the outer periphery of a sample

Abstract

The present application belongs to the technical field of air impact jet flow cooling, and particularly relates to a nozzle structure and device for cooling the periphery of a sample based on impact heat exchange, wherein the nozzle structure comprises a nozzle shell, a nozzle inner rod and an inner flow channel conical part; the inner wall of the nozzle shell, the outer wall of the nozzle inner rod and the outer wall of the inner flow channel conical part form an annular contraction flow channel; the outermost end of the lower end of the inner flow channel conical part and the lowermost end of the flow channel cavity of the nozzle shell form an annular gap cooling gas nozzle; a plurality of cooling gas inlet joints are arranged on the nozzle shell corresponding to the upper end position of the flow channel cavity. The nozzle structure provided by the present application can be used alone or in combination with two nozzle structures. During the cooling process, the compressed cooling gas flow passes through the annular contraction flow channel, so that the gas flow rate is accelerated, and finally the gas is sprayed out from the annular gap cooling gas nozzle and impacts the surface of the sample, so as to achieve the effect of cooling the outer edge boundary of the sample.

Description

Technical Field

[0001] This invention belongs to the field of air impingement jet cooling technology, specifically relating to a nozzle structure and device for cooling the outer periphery of a sample based on impingement heat transfer, suitable for experimental research on situations where the local temperature of the outer ring of the test piece changes rapidly. Background Technology

[0002] When a fluid flows over a solid surface, heat exchange occurs between the fluid and the solid at the fluid-solid interface; this process is called convective heat transfer in engineering. Generally speaking, all other things being equal, the faster the fluid velocity, the greater the rate of heat transfer. To obtain a larger surface heat transfer coefficient in a localized area of ​​the heat exchange surface (especially during rapid cooling or thermal shock), convective heat transfer using impinging jets is generally employed.

[0003] Thermal fatigue testing refers to the rapid heating and cooling of a designed structural test specimen using external heating and cooling sources, causing localized instantaneous thermal strain and stress. Currently, cooling methods used in thermal fatigue testing mainly include compressed air cooling, water tank cooling, and water flow cooling. Water tank cooling and water flow cooling offer faster cooling rates than compressed air cooling, but their control processes are more complex, and the cooling effect is relatively difficult to control. Compressed air cooling offers various cooling methods; impact cooling is commonly used in thermal fatigue testing, but most existing cooling channels are designed with circular nozzles, meaning the localized area cooled by the ejected cooling air is circular or other shapes. Cooling the localized areas at the outer edge of the specimen is relatively difficult. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a nozzle structure and device for cooling the outer periphery of a sample based on impact heat transfer, enabling simple and convenient cooling of localized areas of the workpiece using compressed air.

[0005] This invention is implemented as follows: a nozzle structure and device for cooling the outer periphery of a sample based on impact heat transfer is provided, including a nozzle shell, an inner nozzle rod, and an inner flow channel cone. The nozzle shell is internally a flow channel cavity, with its lower end open to the outside. The inner nozzle rod is disposed within the flow channel cavity, and the inner flow channel cone is connected to the lower end of the inner nozzle rod. The inner wall of the nozzle shell, the inner nozzle rod, and the outer wall of the inner flow channel cone form an annular contraction flow channel. The outermost edge of the lower end of the inner flow channel cone and the lowermost end of the flow channel cavity of the nozzle shell form an annular slit cooling gas nozzle. Several cooling gas inlet connectors are provided on the nozzle shell corresponding to the upper end of the flow channel cavity.

[0006] Preferably, the flow channel cavity includes a first cavity, a second cavity, and a third cavity. The first cavity and the third cavity are both cylindrical cavities, and the diameter of the third cavity is larger than that of the first cavity. The second cavity is an expanded oral cavity, with its upper end connected to the first cavity and its lower end connected to the third cavity. The upper end of the inner flow channel conical component is located at the junction of the second cavity and the third cavity, and the lower end of the inner flow channel conical component is a certain distance away from the lower end of the nozzle shell. The cooling gas inlet connector is connected to the first cavity.

[0007] Further preferably, the nozzle inner rod includes an inner rod base column and a conical positioning component. The conical positioning component has a shoulder. The inner flow channel conical component is sleeved on the conical positioning component and snapped into the shoulder position. The lower end of the inner rod base column is connected to the upper end of the conical positioning component, and the upper end of the inner flow channel conical component is snapped into the connection between the inner rod base column and the conical positioning component.

[0008] Further preferably, an arc-shaped notch is provided on the outer edge of the lower end of the inner rod base column, and an arc-shaped notch is also provided on the outer edge of the upper end of the conical positioning component. The upper end of the inner flow channel conical component is a ring of rounded protrusions. When the inner rod base column and the conical positioning component are connected, the rounded protrusions are precisely engaged in the annular groove formed by the arc-shaped notch of the inner rod base column and the conical positioning component.

[0009] In a further preferred embodiment, the inner wall of the inner flow channel tapered component is connected to an annular baffle, which is engaged with the shoulder of the shaft.

[0010] Further preferably, the nozzle inner rod also includes a nozzle adjusting component, with a through hole at the top of the nozzle housing, through which the nozzle adjusting rod passes and is threadedly connected to the inner rod base column.

[0011] Further preferably, the slit width of the annular slit cooling gas nozzle is b, where b is less than 1 mm.

[0012] Further preferably, the distance between the annular slit cooling air nozzle and the part to be cooled is h, where b = h / 10.

[0013] The present invention also provides a cooling gas nozzle device for cooling the outer periphery of a sample based on impact heat transfer, comprising two of the above-mentioned cooling gas nozzle structures for cooling the outer periphery of a sample based on impact heat transfer. In one cooling gas nozzle structure, the end of the conical positioning member away from the inner rod base column is provided with an integrally connected positioning screw. In the other cooling gas nozzle structure, the end of the conical positioning member away from the inner rod base column is provided with a positioning groove. The length of the positioning screw is longer than the depth of the positioning groove. The positioning screw is connected in the positioning groove, and the part to be cooled is connected to the positioning screw.

[0014] Preferably, a positioning hole is set in the center of the part to be cooled, and the part to be cooled is connected to the positioning screw through the positioning hole. The depth of the positioning hole is at least 4mm less than the length of the positioning screw.

[0015] Compared with the prior art, the advantages of the present invention are as follows:

[0016] This invention provides a cooling gas nozzle structure and device for cooling the outer periphery of a sample based on impact heat transfer. It can be used alone or in combination of two nozzle structures. During the cooling process, the compressed cooling gas flow passes through an annular contraction channel, increasing the gas velocity, and finally exits from the annular slit cooling gas nozzle, impacting the sample surface to achieve the effect of cooling the outer edge of the sample. The cooling area is a ring-shaped region extending outwards from the centerline of the annular slit cooling gas nozzle by 2–3 cm. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a nozzle structure for cooling the outer periphery of a sample based on impact heat transfer, as provided in Embodiment 1 of the present invention.

[0018] Figure 2 This is a cross-sectional view of the nozzle device for cooling the outer periphery of a sample based on impact heat transfer, provided in Embodiment 2 of the present invention.

[0019] Figure 3 This is a perspective view of the nozzle device for cooling the outer periphery of a sample based on impact heat transfer, provided in Embodiment 2 of the present invention.

[0020] Figure 4 This is a perspective view of the nozzle device for cooling the outer periphery of a sample based on impact heat transfer, provided in Embodiment 2 of the present invention. Detailed Implementation

[0021] 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 of the invention and are not intended to limit the invention.

[0022] Example 1

[0023] refer to Figure 1This embodiment provides a nozzle structure for cooling the outer periphery of a sample based on impact heat transfer, including a nozzle shell 1, an inner nozzle rod, and an inner flow channel cone 2. The nozzle shell 1 has a flow channel cavity inside, with the lower end of the flow channel cavity open to the outside. The inner nozzle rod is disposed in the flow channel cavity, and the inner flow channel cone 2 is connected to the lower end of the inner nozzle rod. The inner wall of the nozzle shell 1, the inner nozzle rod, and the outer wall of the inner flow channel cone 2 form an annular contraction flow channel. The outermost edge of the lower end of the inner flow channel cone 2 and the lower end of the flow channel cavity of the nozzle shell 1 form an annular slit cooling gas nozzle 3. Several cooling gas inlet connectors 4 are provided on the nozzle shell 1 corresponding to the upper end of the flow channel cavity.

[0024] To ensure a strictly constricted flow channel is formed, no rounded or chamfered corners are made at the location of the annular slit cooling gas nozzle 3, specifically at the bottom of the inner flow channel cone 2 and the bottom of the inner wall of the flow channel cavity. When cooling is required for a localized area around the outer periphery of the sample, the sample is installed below the nozzle structure. A suitable distance from the annular slit cooling gas nozzle 3 is selected based on the sample size and the specific location requiring cooling. The gas source is connected to the cooling gas inlet connector 4, ensuring a certain gas source pressure (total pressure should not be less than 0.3 MPa), and cooling of the sample can then begin. During the cooling process, the compressed cooling gas flow enters the annular constricted flow channel formed by the nozzle inner rod, nozzle outer shell 1, and inner flow channel cone 2 from the cooling gas inlet connector 4. The gas velocity increases as it passes through the constricted flow channel, and finally, it is ejected from the annular slit cooling gas nozzle 3, impacting the sample surface to achieve the effect of cooling the outer edge of the sample. Figure 1 The middle arrow indicates the direction of the cooling airflow.

[0025] During the cooling process, the total pressure of the gas source is continuously adjusted, and the temperature at the monitoring point of the sample is measured by installing thermocouples or other temperature measurement methods to obtain the cooling rate of the target area. When the cooling rate reaches the expected value, the total pressure of the gas source at this time is recorded.

[0026] As one configuration of the flow channel cavity, the flow channel cavity includes a first cavity, a second cavity, and a third cavity. The first cavity and the third cavity are both cylindrical cavities, and the diameter of the third cavity is larger than that of the first cavity. The second cavity is an expanded oral cavity, with its upper end connected to the first cavity and its lower end connected to the third cavity. The upper end of the inner flow channel conical member 2 is located at the junction of the second cavity and the third cavity, and the lower end of the inner flow channel conical member 2 is a certain distance away from the lower end of the nozzle housing 1 to prevent the cooling gas from spreading outwards excessively. The cooling gas inlet connector 4 is connected to the first cavity.

[0027] Cooling gas enters the first and second chambers through the cooling gas inlet connector 4. Since the upper end of the inner flow channel cone 2 is located at the junction of the second and third chambers, and the third chamber is a cylindrical chamber, the constriction flow channel gradually contracts at the position of the third chamber.

[0028] As a specific connection and fixing method between the inner flow channel conical component 2 and the nozzle inner rod, and as an improvement to the technical solution, the nozzle inner rod includes an inner rod base column 5 and a conical component positioning component 6. The conical component positioning component 6 is provided with a shoulder. The inner flow channel conical component 2 is sleeved on the conical component positioning component 6 and snapped into the shoulder position. The lower end of the inner rod base column 5 is connected to the upper end of the conical component positioning component 6, and the upper end of the inner flow channel conical component 2 is snapped into the connection between the inner rod base column 5 and the conical component positioning component 6.

[0029] To secure the inner flow channel conical component 2, as an improvement to the technical solution, an arc-shaped notch is provided on the outer edge of the lower end of the inner rod base column 5, and an arc-shaped notch is also provided on the outer edge of the upper end of the conical component positioning component 6. The upper end of the inner flow channel conical component 2 is a rounded protrusion. When the inner rod base column 5 and the conical component positioning component 6 are connected, the rounded protrusion is precisely engaged in the annular groove formed by the arc-shaped notch of the inner rod base column 5 and the conical component positioning component 6.

[0030] During installation, the inner flow channel conical part 2 is fitted onto the conical part positioning part 6. The rounded protrusion at the upper end of the inner flow channel conical part 2 matches the arc-shaped notch of the conical part positioning part 6. Then, the inner rod base column 5 is connected to the conical part positioning part 6, so that the arc-shaped notch at the lower end of the inner rod base column 5 also matches the rounded protrusion. In this way, the arc-shaped notch of the inner rod base column 5 and the conical part positioning part 6 form an annular groove, which perfectly holds the inner flow channel conical part 2 in place.

[0031] To facilitate the inner flow channel tapered component 2 being secured on the tapered component positioning component 6, as an improvement to the technical solution, an annular baffle 7 is connected to the inner wall of the inner flow channel tapered component 2, and the annular baffle 7 is engaged at the shoulder position.

[0032] To facilitate the adjustment and installation of the nozzle inner rod, as an improvement to the technical solution, the nozzle inner rod also includes a nozzle adjusting component 8. A through hole is provided at the top of the nozzle housing 1, through which the nozzle adjusting rod 8 passes and is threadedly connected to the inner rod base column 5.

[0033] Typically, the slit width of the annular slit cooling gas nozzle 3 is set to b, where b is less than 1 mm. The distance between the annular slit cooling gas nozzle 3 and the sample to be cooled is h, where b = h / 10. This is a conventional cooling setup. During the cooling process, the cooling area of ​​the sample is a ring-shaped region extending outward from the centerline of the annular slit cooling gas nozzle by 2 to 3 b.

[0034] It can make the cooling gas flow at a speed of up to 200 m / s from the outlet slit to impact the sample surface for cooling. It is suitable for rapid cooling of a local area of ​​the sample, with a local cooling rate of up to 200 K / s. It is simple to operate and the cooling effect is easy to control.

[0035] Example 2

[0036] refer to Figure 2 , Figure 3 and Figure 4 This embodiment provides a nozzle device for cooling the outer periphery of a sample based on impact heat transfer, including two nozzle structures for cooling the outer periphery of a sample based on impact heat transfer as described in Embodiment 1. In one cooling gas nozzle structure, the tapered positioning member 6 is provided with an integrally connected positioning screw 9 at one end away from the inner rod base column 5. In the other cooling gas nozzle structure, the tapered positioning member 6 is provided with a positioning groove at one end away from the inner rod base column 5. The length of the positioning screw 9 is longer than the depth of the positioning groove. The positioning screw 9 is connected in the positioning groove, and the sample to be cooled is connected to the positioning screw 9.

[0037] This embodiment is designed for situations where it is sometimes necessary to cool the corresponding positions of the upper and lower parts of the sample simultaneously. The sample is installed on the positioning screw 9, and then the positioning screw 9 is installed into the positioning groove. The position of the sample is adjusted so that the distance between the sample and the annular slit cooling air nozzle 3 of the upper nozzle structure is the same as the distance between the sample and the annular slit cooling air nozzle 3 of the lower nozzle structure. Then, the method in Embodiment 1 is used to supply air to both nozzle structures simultaneously to cool the same positions of the upper and lower parts of the sample.

[0038] To facilitate the connection of the sample to the positioning screw 9, as an improvement to the technical solution, a positioning hole is set in the center of the part to be cooled, and the part to be cooled is connected to the positioning screw 9 through the positioning hole. The depth of the positioning hole is at least 4 mm smaller than the length of the positioning screw 9.

Claims

1. A nozzle structure for cooling the outer periphery of a sample based on impact heat transfer, characterized in that, The device includes a nozzle housing (1), a nozzle inner rod, and an inner flow channel cone (2). The nozzle housing (1) has a flow channel cavity inside, with the lower end of the flow channel cavity open to the outside. The nozzle inner rod is located inside the flow channel cavity, and the inner flow channel cone (2) is connected to the lower end of the nozzle inner rod. The inner wall of the nozzle housing (1) and the outer wall of the nozzle inner rod and the inner flow channel cone (2) form an annular contraction flow channel. The outermost edge of the lower end of the inner flow channel cone (2) and the lower end of the flow channel cavity of the nozzle housing (1) form an annular slit cooling gas nozzle (3). Several cooling gas inlet connectors (4) are provided on the nozzle housing (1) corresponding to the upper end of the flow channel cavity. The nozzle inner rod includes an inner rod base column (5) and a conical positioning component (6). The conical positioning component (6) has a shoulder. The inner flow channel conical component (2) is sleeved on the conical positioning component (6) and snapped into the shoulder position. The lower end of the inner rod base column (5) is connected to the upper end of the conical positioning component (6), and the upper end of the inner flow channel conical component (2) is snapped into the connection between the inner rod base column (5) and the conical positioning component (6). An arc-shaped notch is provided at the lower outer edge of the inner rod base column (5), and an arc-shaped notch is also provided at the upper outer edge of the conical positioning component (6). The upper end of the inner flow channel conical component (2) is a round head protrusion. When the inner rod base column (5) and the conical positioning component (6) are connected, the round head protrusion is just locked in the annular groove formed by the arc-shaped notch of the inner rod base column (5) and the conical positioning component (6). The inner wall of the inner flow channel tapered part (2) is connected to an annular baffle (7), which is engaged at the shoulder position.

2. The nozzle structure for cooling the outer periphery of a sample based on impact heat transfer according to claim 1, characterized in that, The flow channel cavity includes a first cavity, a second cavity, and a third cavity. The first cavity and the third cavity are both cylindrical cavities. The diameter of the third cavity is larger than that of the first cavity. The second cavity is an expanded oral cavity. The upper end of the second cavity is connected to the first cavity, and the lower end is connected to the third cavity. The upper end of the inner flow channel cone (2) is located at the junction of the second cavity and the third cavity. The lower end of the inner flow channel cone (2) is a certain distance away from the lower end of the nozzle shell (1). The cooling gas inlet connector (4) is connected to the first cavity.

3. The nozzle structure for cooling the outer periphery of a sample based on impact heat transfer according to claim 1, characterized in that, The nozzle inner rod also includes a nozzle adjusting rod (8), which has a through hole at the top of the nozzle housing (1). The nozzle adjusting rod (8) passes through the through hole and is threadedly connected to the inner rod base column (5).

4. The nozzle structure for cooling the outer periphery of a sample based on impact heat transfer according to claim 1, characterized in that, The slit width of the annular slit cooling air nozzle (3) is b, which is less than 1 mm.

5. The nozzle structure for cooling the outer periphery of a sample based on impact heat transfer according to claim 4, characterized in that, The distance between the annular slit cooling gas nozzle (3) and the sample to be cooled is h, b=h / 10.

6. A nozzle device for cooling the outer periphery of a sample based on impact heat transfer, characterized in that, The invention includes two nozzle structures for cooling the outer periphery of a sample based on impact heat transfer as described in any one of claims 1-5. In one of the cooling gas nozzle structures, the conical positioning member (6) is provided with an integrally connected positioning screw (9) at one end away from the inner rod base column (5). In the other cooling gas nozzle structure, the conical positioning member (6) is provided with a positioning groove at one end away from the inner rod base column (5). The length of the positioning screw (9) is longer than the depth of the positioning groove. The positioning screw (9) is connected in the positioning groove, and the sample to be cooled is connected to the positioning screw (9).

7. The nozzle device for cooling the outer periphery of a sample based on impact heat transfer according to claim 6, characterized in that, A positioning hole is set in the center of the part to be cooled. The part to be cooled is connected to the positioning screw (9) through the positioning hole. The depth of the positioning hole is at least 4 mm less than the length of the positioning screw (9).

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