A curved profiling nozzle based on the cross-sectional profile of heavy rail head

Abstract

A curved, contoured nozzle based on the cross-sectional profile of a heavy rail head addresses the problem of conventional air jet cooling, where the external flow fields of the air jets often interfere with each other, forming overlapping dead zones. This results in poor cooling uniformity at the rail head after quenching, impacting the quality of the heavy rail. The nozzle comprises a nozzle base, an air inlet disposed at the upper end of the nozzle base, a rail head-conforming recess disposed at the lower end of the nozzle base, a nozzle outlet disposed within the rail head-conforming recess, and a connecting flange for connecting to an air supply system at the nozzle inlet. The nozzle has a rational design and a compact structure. The curved, contoured outlet profile smoothes airflow distribution, increasing the cooling rate of the heavy rail head during air-cooled quenching, ensuring excellent cooling uniformity, and significantly improving the production quality of heavy rails.

Description

Technical Field

[0001] The present invention belongs to the technical field of air-cooling quenching, and specifically relates to a curved profiling nozzle based on the cross-sectional profile of a heavy rail head, which utilizes a curved profiling outlet profile to make the air flow distribution smoother, thereby increasing the cooling rate of the heavy rail head during air-cooling quenching, achieving good cooling uniformity, and significantly improving the production quality of the heavy rail. Background Art

[0002] In-line air-cooling quenching of heavy rails is an advanced heat treatment process that utilizes the residual heat from rolling directly into a jet cooling device for quenching. It offers advantages such as high production efficiency, environmental friendliness, insensitivity to the rail surface condition, and easily controllable cooling rates. Because compressed air is used as the cooling medium, air-cooling quenching offers improved cooling uniformity compared to spray and water spray quenching. Consequently, this quenching process has been widely adopted by major steel mills both domestically and internationally. However, current air-cooling quenching of heavy rails utilizes a combination of multiple conventional nozzles. This traditional multi-nozzle air-cooling method often interferes with each other due to the arrangement of the nozzles, creating overlapping dead zones. This leads to poor cooling uniformity at the rail head after quenching, impacting rail quality. Furthermore, research on air-cooling quenching devices for heavy rails is limited, and further research is needed on nozzle design requirements and factors influencing quenching. Therefore, improvements are needed to existing air-cooling methods and devices for air-cooling quenching of heavy rail heads. Summary of the Invention

[0003] The present invention is aimed at the above problems and provides a curved profiling nozzle based on the cross-sectional profile of the heavy rail head, which utilizes a curved profiling outlet profile to make the air flow distribution smoother, thereby increasing the cooling rate of the heavy rail head during air-cooling quenching, improving the cooling uniformity, and significantly improving the production quality of the heavy rail.

[0004] The technical solution adopted by the present invention is: the curved profiling nozzle based on the cross-sectional profile of the heavy rail head includes a nozzle base, which is characterized in that: the upper end of the nozzle base is provided with a nozzle air inlet, the lower end of the nozzle base is provided with a rail head conformal recess, and the interior of the rail head conformal recess is provided with a nozzle air outlet; and, the nozzle air inlet is also provided with a connecting flange for connecting to an air supply system.

[0005] The nozzle base is a split assembly structure, consisting of a nozzle-side base I and a nozzle-side base II, which are symmetrically assembled together. A sealing strip is provided between the two. This split assembly structure facilitates the production, processing, and subsequent maintenance of the nozzle base.

[0006] The nozzle-side base I and nozzle-side base II have the same structure, each comprising a side base body. A nozzle cavity is provided on one side of the side base body where they are assembled and bonded. The upper portion of the nozzle cavity is connected to the nozzle air inlet, and the lower portion is connected to the nozzle air outlet. The nozzle cavities of the two symmetrically arranged nozzle-side bases I and II are combined to form a flow channel for the cooling airflow.

[0007] The nozzle cavity is symmetrically provided with cavity side straight surfaces on either side. The lower ends of these cavity side straight surfaces are symmetrically provided with cavity contraction curved surfaces. The ends of these cavity contraction curved surfaces on either side are connected to the ends of the nozzle air outlet. The cavity side straight surfaces on either side of the nozzle cavity guide the flow of cooling air, and the cavity contraction curved surfaces at the nozzle air outlet smooth the airflow distribution, ensuring more uniform cooling of the heavy rail head.

[0008] The curve equation of the cavity contraction surface is:

[0009]

[0010] Where: x , y are the coordinates of the point on the curve; l 1 is the width of the curve; y e is the height of the bottom end of the curve; y 0 -y e is the height of the curve.

[0011] In the curve equation of the cavity contraction surface,

[0012] l 1=( a - c ) / 2

[0013] Where: a is the width of the nozzle inlet, c is the width of the nozzle outlet.

[0014] The curve equation of the cavity contraction surface must satisfy y 0> y e The origin of the coordinate system of the curve (0,0) is located directly below the connection point between the curve of the cavity contraction surface and the nozzle outlet. The curve is ( l 1, y 0) starting point to connect with the cavity side surface, the curve is (0, y e ) as the end point to connect with the nozzle outlet.

[0015] Symmetrically arranged cavity transition curved surfaces are provided between the upper end of the cavity contraction curved surface and the lower end of the cavity side straight surface to prevent airflow instability caused by sudden changes in the flow area and further ensure uniform airflow.

[0016] The curve equation of the cavity transition surface is:

[0017] R = y e × l 1 / [ l 1 - ( y 0- y e )]

[0018] Where: y e is the height of the bottom end of the curve of the cavity contraction surface; l 1 is the width of the curve of the cavity contraction surface; y 0 -y e is the height of the curve of the cavity contraction surface.

[0019] Side base connecting holes are provided on both sides of the side base body. Connecting sealing grooves are provided between the side base connecting holes and the side ends of the central nozzle cavity, and sealing strips are provided in the connecting sealing grooves. A connecting flange is also provided at the upper end of the side base body, at the location of the nozzle air inlet. The connecting flange is provided with flange connecting holes. The side base connecting holes are used to tightly connect the two symmetrically arranged nozzle side bases I and II together. The sealing strips provided in the connecting sealing grooves enhance the sealing properties of the connection. The nozzle base, composed of nozzle side bases I and II, is connected to the air supply system using the flange connecting holes provided on the connecting flange.

[0020] The beneficial effects of the present invention are as follows: Since the present invention adopts a nozzle base, the upper end of the nozzle base is provided with a nozzle air inlet, the lower end of the nozzle base is provided with a rail head conformal recess, the interior of the rail head conformal recess is provided with a nozzle air outlet, and the nozzle air inlet is provided with a structural form of a connecting flange for connecting to the air supply system, the design is reasonable and the structure is compact. The curved profile outlet profile shape is used to make the air flow distribution smoother, which can increase the cooling rate of the heavy rail head during air-cooling quenching and improve the cooling uniformity. When the curved profile nozzle based on the cross-sectional profile of the heavy rail head is used to spray-cool the heavy rail, the air flow passes through the restriction of the nozzle base cavity, passes through the nozzle air outlet at the rail head conformal recess, and is distributed more evenly around the heavy rail head, thereby making the upper tread portion of the heavy rail head the first part to be cooled. Because the function of heavy rail is to guide the wheels of locomotives and vehicles forward and provide a continuous, smooth and least-resistance rolling surface for the wheels. The upper tread of the heavy rail head serves as the contact working surface with the wheels and bears the huge pressure of the wheels. Therefore, the cooling of the heavy rail head during the air spraying process of this curved profiling nozzle can significantly improve the production quality of heavy rails. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 yes Figure 1 A-direction view.

[0023] Figure 3 yes Figure 1 A structural schematic diagram of the nozzle side substrate II (or nozzle side substrate I) in FIG.

[0024] Figure 4 yes Figure 3 Graph of the cavity shrinkage surface in .

[0025] Figure 5 This is a schematic diagram of a usage state of the present invention.

[0026] Figure 6 It is a schematic diagram of the existing common air nozzle air cooling form.

[0027] Figure 7 It is a velocity streamline diagram when the present invention sprays air.

[0028] Figure 8 This is the velocity streamline diagram when an ordinary air nozzle is ejecting air.

[0029] Figure 9 This is a temperature contour distribution diagram of the heavy rail cross section during the jet quenching process of the present invention.

[0030] Figure 10This is the temperature contour distribution diagram of the heavy rail cross section during air quenching using a common air nozzle.

[0031] Explanation of the serial numbers in the figure: 1 nozzle side base I, 2 nozzle side base II, 3 nozzle air inlet, 4 nozzle air outlet, 5 rail head conformal recess, 6 connecting flange, 7 sealing strip, 8 side base body, 9 nozzle cavity, 10 cavity side straight surface, 11 cavity transition surface, 12 cavity contraction surface, 13 connecting sealing groove, 14 side base connecting hole, 15 flange connecting hole, 16 heavy rail, 17 heavy rail head, 18 ordinary air nozzle. DETAILED DESCRIPTION

[0032] according to Figures 1 to 10 The specific structure of the present invention is described in detail. The curved contoured nozzle based on the cross-sectional profile of the heavy rail head includes a nozzle base. The nozzle base is a split assembly structure. The nozzle base includes a nozzle side base Ⅰ1 and a nozzle side base Ⅱ2. The nozzle side base Ⅰ1 and the nozzle side base Ⅱ2 are symmetrically assembled together; and a sealing strip 7 is also provided between the nozzle side base Ⅰ1 and the nozzle side base Ⅱ2; the split assembly structure is utilized to facilitate the production, processing and subsequent maintenance of the nozzle base. The upper end of the nozzle base is provided with a nozzle air inlet 3, and the lower end of the nozzle base is provided with a rail head conforming recess 5 for matching the shape of the heavy rail head 17. The interior of the rail head conforming recess 5 is provided with a nozzle air outlet 4; and a connecting flange 6 for connecting to the air supply system is also provided at the upper end of the nozzle base and the nozzle air inlet 3.

[0033] The nozzle-side base I1 and nozzle-side base II2 of the nozzle base have the same structure, each including a side base body 8. A nozzle cavity 9 is provided on the side of the side base body 8 where it is assembled and bonded to the other side base body 8. The upper portion of the nozzle cavity 9 is connected to the nozzle air inlet 3 at the upper end of the nozzle base; the lower portion of the nozzle cavity 9 is connected to the nozzle air outlet 4 at the lower end of the nozzle base. The symmetrical arrangement of the nozzle cavities 9 on the nozzle-side base I1 and the nozzle-side base II2 forms a complete cooling airflow channel.

[0034] Side base connecting holes 14 are provided on both sides of the side base body 8. Connecting sealing grooves 13 are provided between the side base connecting holes 14 and the side ends of the central nozzle cavity 9. Sealing strips 7 are provided in the connecting sealing grooves 13. Thus, the two symmetrically arranged nozzle side bases I1 and II2 are tightly connected together using the side base connecting holes 14. The sealing strips 7 provided in the connecting sealing grooves 13 enhance the sealing performance of the connection. At the same time, a connecting flange 6 is provided at the upper end of the side base body 8, at the location of the nozzle air inlet 3. Flange connecting holes 15 are provided on the connecting flange 6. The nozzle base, which is assembled from the nozzle side bases I1 and II2, is connected to the air supply system through the flange connecting holes 15 provided on the connecting flange 6.

[0035] The nozzle cavity 9 of the nozzle side base Ⅰ1 and the nozzle side base Ⅱ2 is symmetrically provided with cavity side straight surfaces 10; the lower ends of the cavity side straight surfaces 10 on both sides are respectively provided with symmetrically arranged cavity contraction curved surfaces 12; the lower ends of the cavity contraction curved surfaces 12 on both sides are respectively connected to the left and right ends of the nozzle air outlet 4 at the rail head conformal recess 5 at the lower end of the side base body 8; and then the cavity side straight surfaces 10 on both sides of the nozzle cavity 9 are used to guide the flow of the cooling airflow, and the cavity contraction curved surface 12 at the nozzle air outlet 4 is used to make the airflow distribution smoother, so that the cooling of the heavy rail head 17 is more uniform. In order to further ensure the uniform flow of the airflow, symmetrically arranged cavity transition curved surfaces 11 are respectively provided between the upper ends of the cavity contraction curved surfaces 12 on both sides and the lower ends of the cavity side straight surfaces 10 to prevent the phenomenon of unstable airflow caused by sudden changes in the flow area.

[0036] The curve equation of the cavity contraction surface 12 of the nozzle cavity 9 is as follows:

[0037]

[0038] Where: x , y are the coordinates of the points on the curve; l 1 is the width of the curve; y e is the height of the bottom end of the curve; y 0 -y e is the height of the curve. And, l 1=( a - c ) / 2, where a is the width of the nozzle air inlet 3, c is the width of the nozzle outlet 4.

[0039] The curve equation of the cavity contraction surface 12 must satisfy y 0> ye The origin (0,0) of the coordinate system of the curve is located directly below the connection point between the curve of the cavity contraction surface 12 and the nozzle outlet 4. l 1, y 0) starting point, and then connected with the cavity side straight surface 10; the curve is (0, y e ) as the end point to connect with the nozzle outlet 4.

[0040] When the curved profiling nozzle based on the cross-sectional profile of the heavy rail head is used, first, the two symmetrically arranged nozzle side bases Ⅰ1 and nozzle side bases Ⅱ2 are tightly connected together through the side base connecting hole 14, and the sealing strip 7 provided in the connecting sealing groove 13 is used to increase the connection sealing; at the same time, the nozzle cavities 9 on the two mutually symmetrically arranged nozzle side bases Ⅰ1 and nozzle side bases Ⅱ2 are combined to form a complete flow channel for the cooling airflow, and the upper part of the nozzle cavity 9 is connected to the nozzle air inlet 3, and the lower part of the nozzle cavity 9 is connected to the nozzle air outlet 4. Then, the nozzle base assembled by the nozzle side base Ⅰ1 and the nozzle side base Ⅱ2 is connected to the air supply port of the air supply system through the flange connecting hole 15 provided on the connecting flange 6. Afterwards, the rail head conforming recess 5 at the lower part of the nozzle base of the curved profiling nozzle is arranged directly above the heavy rail head 17 of the heavy rail 16 (such as Figure 5 As shown), the heavy rail head 17 is then cooled by air cooling quenching.

[0041] Example:

[0042] The distance from the bottom end to the top end of the nozzle side substrate Ⅰ1 and the nozzle side substrate Ⅱ2 is set to 130mm; in the curve equation of the cavity contraction surface 12 of the nozzle cavity 9 (combined with Figure 4 ), take the height of the contraction section as 23.61mm, that is: y 0 -y e =23.61mm; and by the formula l 1 =( a - c ) / 2, determine the curve width, l 1 = (150.7mm-90.7mm) / 2=30mm; at the same time, take y e =10mm, that is, the distance between the rail head conformal recess 5 at the bottom of the nozzle base and the heavy rail head 17 of the heavy rail 16 is 10mm. y 0=23.61+ y e =23.61+10=33.61mm.

[0043] Therefore, the curve line shape of the cavity contraction surface 12 starts at (-30, 33.61) and is connected to the lower end of the cavity side straight surface 10; and the curve line shape of the cavity contraction surface 12 ends at (0, 10) and is connected to one end of the nozzle outlet 4 at the rail head conformal recess 5. In addition, the two cavity contraction surfaces 12 are symmetrically arranged at the lower ends of the cavity side straight surfaces 10 on both sides of the nozzle cavity 9. In addition, the curve radius of the cavity transition surface 11 set between the upper ends of the cavity contraction surfaces 12 on both sides and the lower ends of the cavity side straight surfaces 10 is R = y e × l 1 / [ l 1 -( y 0- y e )], where the parameters are the same as those in the curve equation of the cavity contraction surface 12, and the curve radius is determined R =46.95mm; this serves to transition between the cavity-side straight surface 10 and the cavity contraction curved surface 12, effectively preventing airflow instability caused by sudden changes in the flow area. Simultaneously, the cavity transition curved surface 11 is tangentially connected to the cavity-side straight surface 10, and the cavity transition curved surface 11 is also tangentially connected to the cavity contraction curved surface 12.

[0044] Under the condition of keeping the same air jet pressure (for example: 0.02MPa) and inlet area, the cooling structure of the curved profiling nozzle based on the cross-sectional profile of the heavy rail head of the present invention (such as Figure 5 As shown) and the ordinary nozzle 18 spray cooling form (as Figure 6 The average cooling rate of 17 temperature monitoring points on the heavy rail head was used as an evaluation indicator for rail head cooling rate. A larger average value indicates a higher cooling rate. The standard deviation of the cooling rate was used as an evaluation indicator for rail head cooling uniformity. A smaller standard deviation indicates better cooling uniformity.

[0045] By observing the motion law of the air flow in the velocity streamline diagram, it can be seen that when the heavy rail 16 is cooled by the ordinary air nozzle 18, the air flow is mainly concentrated at the lower jaw of the heavy rail head 17 (such as Figure 8 As shown in FIG. 1 ), the first part of the heavy rail 16 to be cooled is the lower jaws on both sides of the heavy rail head 17. When the heavy rail 16 is cooled by air jetting using the cooling structure of the curved profiling nozzle based on the cross-sectional profile of the heavy rail head of the present invention, the air flow is restricted by the nozzle cavity 9 of the nozzle base, and after passing through the nozzle outlet 4 at the rail head conformal recess 5, it is distributed more evenly around the heavy rail head 17 (as shown in FIG. 1 ). Figure 7As shown in the figure, the first part of the heavy rail 16 to be cooled is the upper tread of the rail head 17. Since the heavy rail 16 primarily guides the wheels of rolling stock and provides a continuous, smooth, and minimally resisting rolling surface, the upper tread of the rail head 17, acting as the working contact surface with the wheels, bears the immense pressure from the wheels. Therefore, cooling the upper tread of the rail head 17 during the air jet process using this curved, contoured nozzle, designed based on the cross-sectional profile of the heavy rail head, can significantly improve the production quality of the heavy rail 16.

[0046] When the heavy rail 16 is spray-cooled for 100 seconds using the curved profiling nozzle based on the cross-sectional profile of the heavy rail head of the present invention, the average cooling rate of the heavy rail 16 is 3.39°C / s, and the standard deviation of the cooling rate is 0.45. Compared with the average cooling rate of 2.91°C / s and the standard deviation of the cooling rate of 0.69 when the heavy rail 16 is spray-cooled using the ordinary air nozzle 18, the experimental results show that the use of the curved profiling nozzle for spray cooling of the heavy rail 16 can effectively improve the cooling rate and cooling uniformity of the heavy rail.

Claims

1. A curved profiling nozzle based on the cross-sectional profile of a heavy rail head, comprising a nozzle base, characterized in that: The upper end of the nozzle base is provided with a nozzle air inlet (3), the lower end of the nozzle base is provided with a rail head conformal recess (5), and the interior of the rail head conformal recess (5) is provided with a nozzle air outlet (4); and the nozzle air inlet (3) is also provided with a connecting flange (6) for connecting to an air supply system; the nozzle base is a split assembly structure, the nozzle base includes a nozzle side base I (1) and a nozzle side base II (2), the nozzle side base I (1) and the nozzle side base II (2) are symmetrically assembled together; and a sealing strip (7) is provided between the nozzle side base body I (1) and the nozzle side base body II (2); the nozzle side base body I (1) and the nozzle side base body II (2) have the same structure, both comprising a side base body main body (8), a nozzle cavity (9) is provided on the side of the side base body main body (8) where they are assembled and bonded to each other, the upper part of the nozzle cavity (9) is connected to the nozzle air inlet (3), and the lower part of the nozzle cavity (9) is connected to the nozzle air outlet (4); The two sides of the nozzle cavity (9) are symmetrically provided with cavity side straight surfaces (10), and the lower ends of the cavity side straight surfaces (10) are symmetrically provided with cavity contraction curved surfaces (12), and the ends of the cavity contraction curved surfaces (12) on both sides are respectively connected to the two ends of the nozzle air outlet (4); The curve equation of the cavity contraction surface (12) is: Where: x , y are the coordinates of the points on the curve; l 1 is the width of the curve; y e is the height of the bottom end of the curve; y 0 -y e is the height of the curve; Between the upper end of the cavity contraction curved surface (12) and the lower end of the cavity side straight surface (10), symmetrically arranged cavity transition curved surfaces (11) are respectively provided; The curve equation of the cavity transition surface (11) is: R = y e × l 1 / [ l 1 - ( y 0- y e )] Where: y e is the height of the bottom end of the curve of the cavity contraction surface (12); l 1 is the curve width of the cavity contraction surface (12); y 0 -y e is the curve height of the cavity contraction surface (12).

2. The curved profiling nozzle based on the cross-sectional profile of the heavy rail head according to claim 1, characterized in that: In the curve equation of the cavity contraction surface (12), l 1=（ a - c ） / 2 Where: a is the width of the nozzle inlet (3), c is the width of the nozzle outlet (4).

3. The curved profiling nozzle based on the cross-sectional profile of the heavy rail head according to claim 1, characterized in that: The curve equation of the cavity contraction surface (12) must satisfy y 0> y e The origin (0,0) of the coordinate system of the curve is located directly below the connection point between the curve of the cavity contraction surface (12) and the nozzle outlet (4). The curve is ( l 1, y 0) to connect with the cavity side surface (10), the curve is (0, y e ) as the end point to connect with the nozzle outlet (4).

4. The curved profiling nozzle according to claim 1, characterized in that: Side base connecting holes (14) are respectively provided on both sides of the side base body (8), and connecting sealing grooves (13) are respectively provided between the side base connecting holes (14) and the side ends of the middle nozzle cavity (9), and sealing strips (7) are provided in the connecting sealing grooves (13); a connecting flange (6) is further provided at the upper end of the side base body (8) and at the position of the nozzle air inlet (3), and a flange connecting hole (15) is provided on the connecting flange (6).

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