End plate, manufacturing method and tubular heat exchanger

Abstract

The invention discloses an end plate, a manufacturing method and a tubular heat exchanger. A connecting wall A (2) surrounds the edge of the end face of an inner cavity of the end plate (1), radiating pipe connecting holes (3) are distributed in the end plate (1), and the end face of the inner cavity of the end plate (1) is of an inwards-concave / outwards-convex arc-shaped face (4) structure. Brazing layers (5) are laid on the end faces of the inner cavity and the outer cavity of the end plate (1), and the chamfer Rbetween the connecting wall A (2) and the end face of the inner cavity of the end plate (1) is smaller than or equal to 0.5 mm. The invention has the advantages of high pressure resistance, high reliability and high utilization rate of radiating tube arrangement space, and avoids the problems of stress concentration caused by multiple welding and medium leakage at the joint of the end plate and the shell.

Description

Technical Field

[0001] The patent of this invention is applied to the field of shell-and-tube heat exchangers for aircraft engine lubricating oil systems, and specifically relates to an end plate, a manufacturing method and a shell-and-tube heat exchanger. Background Art

[0002] Common end plate structures for aviation shell-and-tube heat exchangers include flat end plate structure, sleeve structure, bent and flanged structure, etc. However, due to the limiting factors of the end plate forming structure, aluminum alloy composite plate brazing material layer, etc., the above end plate structures have problems such as insufficient pressure resistance and low utilization rate of heat dissipation pipe layout space, as follows:

[0003] Flat end plate (see Figure 5 (a)) There are the following disadvantages: 1) The outer circle of the end plate needs to be brazed to the inner wall of the radiator shell. The matching tolerance and coaxiality requirements of the outer diameter of the end plate and the inner diameter of the shell are relatively high. When the matching clearance is large, the brazing quality of the two is affected, and there is a risk of leakage between the tube cavity and the cavity between the tubes; when the matching clearance is small, the operation process of installing the end plate and the heat dissipation tube into the shell cavity is poor; 2) When the shell and the cover are fusion-welded, the brazing seam between the shell and the outer circle of the end plate is too close to the fusion welding position between the shell and the cover, and the fusion welding (argon arc welding) temperature is higher than the brazing temperature, which will cause the brazing seam to be affected, increasing the risk of leakage between the heat dissipation core tube cavity and the cavity between the tubes; 3) The pressure-bearing surface of the pure flat end plate is a plane, which has a small pressure-bearing capacity and is easy to deform.

[0004] Sleeve end plate structure (see Figure 5 Disadvantages of (b)): The sleeve end plate is an end plate assembly formed by fusion welding a sleeve and a pure flat end plate. Strict requirements are placed on the height of the fusion welding weld of the end plate assembly. It is necessary to control the weld height or trim the coarse weld bumps after welding, resulting in low welding strength and increasing the risk of leakage between the tube cavity and the inter-tube cavity caused by weld defects or fatigue cracking.

[0005] Sheet metal flange end plate structure (see Figure 5 (c)) Disadvantages: When aluminum alloy sheet metal is flanged to form a U-shaped end plate structure (the aluminum alloy sheet has its own brazing layer), the sheet metal forming chamfer R is at least 1 times the material thickness δ, resulting in a smaller limiting circle for the arrangement of the heat pipe; the thickness of the end plate is limited by the sheet metal process and raw materials; the pressure-bearing surface of the end plate is a plane, and the pressure-bearing capacity of the plane is small.

[0006] Taking the end plate outer diameter φ = 100mm, the heat pipe hole diameter φ = 2mm, the tube spacing S = 2.6mm, and the heat pipe holes arranged in equal triangles as an example, when the end plate structure with sheet metal flanging of δ = 3mm is adopted, the transfer chamfer R ≥ 3mm, and when R = 3mm, the heat pipe arrangement limit circle DL = 88mm, and the number of pipes is N = 1003. When the integrated machine plus end plate structure is adopted, the thickness of the connecting wall A δ = 3mm, and the transfer chamfer R with the end plate body = 0.5mm, the heat pipe arrangement limit circle DL = 93mm, and the number of pipes is N = 1183; compared with the sheet metal flanging structure, the number of heat pipes arranged increases by 15.2%.

[0007] Taking the end plate outer diameter φ = 100mm, the heat pipe hole diameter φ = 3mm, the tube spacing S = 4mm, and the heat pipe holes arranged in equal triangles as an example, when the sheet metal flanging end plate with δ = 3mm is used, the transfer chamfer R ≥ 3mm, and R = 3mm is taken, the heat pipe arrangement limit circle DL = 88mm, and the number of pipes is N = 420. When the integrated machine plus end plate structure is adopted, the thickness of the connecting wall A δ = 3mm, and the transfer chamfer R between the connecting wall and the end plate body is 0.5mm. At this time, the heat pipe arrangement limit circle DL = 93mm, and the number of pipes is N = 470; the number of heat pipes arranged in the sheet metal flanging structure increases by 10.6%.

[0008] In summary, in order to adapt to the demand trend of engine weight reduction, high pressure resistance and high reliability, and to avoid the problems existing in the above end plate structures, there is an urgent need for an end plate structure with high compressive strength, high reliability, compact heat pipe arrangement, and not restricted by the composite brazing material layer of raw materials. Summary of the invention

[0009] The purpose of the present invention is to improve the pressure bearing capacity of a shell-and-tube heat exchanger, the compactness of the heat dissipation tube arrangement, and the success rate of brazing of a radiator core, and to propose an end plate, a manufacturing method and a shell-and-tube heat exchanger.

[0010] The technical solution of the present invention is: an end plate for a shell-and-tube heat exchanger, the edge of the inner cavity end face of the end plate is surrounded by a connecting wall A, heat dissipation pipe connection holes are distributed on the end plate, and the inner cavity end face of the end plate presents an inwardly concave / outwardly convex arc surface structure; the inner and outer cavity end faces of the end plate are both paved with a brazing layer, and the chamfer R between the connecting wall A and the inner cavity end face of the end plate is ≯0.5mm.

[0011] In the aforementioned end plate for the shell-and-tube heat exchanger, the edge of the outer cavity end surface of the end plate is surrounded by a connecting wall B, and the chamfer R between the connecting wall B and the inner cavity end surface of the end plate is 0.5 mm.

[0012] In the aforementioned end plate for the shell-and-tube heat exchanger, the height of the connecting wall B of the end plate is 10 to 15 mm.

[0013] The aforementioned end plate manufacturing method comprises the following steps:

[0014] S1. A connecting wall A is machined on the inner end surface of the end plate;

[0015] S2. A curved surface is machined on the inner surface of the end plate in the connecting wall A;

[0016] S3. Laying a brazing layer on the curved surface;

[0017] S4. Make a heat dissipation pipe connection hole on the end plate.

[0018] In the aforementioned end plate manufacturing method, in step S1, a connection wall A is processed on the inner cavity end surface of the end plate, and a connection wall B is processed on the outer cavity end surface of the end plate.

[0019] In the aforementioned method for manufacturing the end plate, in step S3, while laying the brazing layer on the arc surface, the brazing layer is also laid on the outer cavity end surface of the end plate.

[0020] In the aforementioned end plate manufacturing method, in step S3, after the brazing layer is laid, heating is performed to make the brazing layer adhere to the end plate.

[0021] The shell-and-tube heat exchanger made of the above-mentioned end plates includes a shell, and the two ends of the shell are respectively connected to the cover A and the cover B through the end plates; a heat dissipation pipe is fixed between the two end plates through the heat dissipation pipe connection hole; the shell is provided with an inter-tube cavity inlet and an inter-tube cavity outlet, and the covers A and B are respectively provided with a tube cavity inlet and a tube cavity outlet.

[0022] In the aforementioned shell-and-tube heat exchanger, when the cavity between the tubes is a high-pressure cavity, the arcuate surface is an outward convex structure, and when the cavity inside the tubes is a high-pressure cavity, the arcuate surface is an inward concave structure.

[0023] In the aforementioned shell-and-tube heat exchanger, the covers A and B are connected to the end surfaces of the corresponding connecting walls B by fusion welding.

[0024] The technical effects of the present invention are:

[0025] Compared with the pure flat end plate structure, the present invention has the following advantages: 1) The end plate of the present invention is provided with a connecting wall B and a cover A / cover B which are fusion-welded, the inner wall of the connecting wall A is connected to the shell by brazing, and the end face of the connecting wall A is also fusion-welded to the shell, which structurally avoids the risk of leakage between the inner cavity of the tube and the cavity between tubes caused by the brazing of the pure flat end plate and the shell; 2) The height of the connecting wall B is greater than 10 mm, and the distance between the fusion weld seam and the brazing seam is greater than the heat-affected zone of the fusion weld, which reduces the risk of leakage between the inner cavity of the tube and the cavity between tubes; 3) The inner cavity end face of the end plate is an inwardly concave / outwardly convex arc surface structure with a large pressure-bearing capacity.

[0026] The advantages of the present invention compared with the sleeve end plate structure: the end plate of the present invention is an integrated structure with the connecting wall A and the connecting wall B, which structurally avoids the risk of leakage between the tube cavity and the inter-tube cavity caused by welding defects or weld fatigue cracking at the sleeve and the end plate.

[0027] The advantages of the present invention over the sheet metal flanged end plate structure are as follows: 1) The heat dissipation pipe arrangement limiting circle of the end plate of the present invention is larger. Under the same end plate structural parameters, the number of pipes is increased by about 10% compared with the sheet metal flanged end plate structure, which greatly improves the heat exchange efficiency and compactness of the radiator; 2) The pressure-bearing surface of the sheet metal flanged end plate is a plane, and the inner cavity end surface of the end plate of the present invention is an inwardly concave / outwardly convex arc surface structure, and its pressure-bearing capacity is greater than that of the sheet metal flanged end plate.

[0028] Example 1: HZSXX stainless steel fuel oil radiator had a cavity failure during the 20MPa pressure test of the tube cavity. Its end plate thickness δ = 3mm. After analysis, it was found that the radiator end plate had insufficient compressive strength and bent when subjected to a large pressure. After bending, the heat dissipation tube was compressed and deformed, and finally broke and the cavity was broken. The bending of the end plate after the pressure test is shown in Figure 6 .

[0029] By optimizing the structural design of the end plate, the inner cavity end face of the end plate is designed to be a concave arc surface, that is, the arc surface and the pressure strain direction of the tube cavity are in the opposite structure. After the improvement, the radiator passed the 20MPa pressure test and the 30MPa ultimate pressure test. At present, with a delivery volume of 200 sets / year, the product has been used without any abnormality, indicating that the improvement measures are effective.

[0030] Example 2: The inner cavity pressure of the HSR-XX aluminum alloy fuel oil radiator reaches 11MPa. Due to the restrictions on heat dissipation efficiency and weight indicators, the end plate adopts a sleeve structure, which is made of aluminum alloy composite plate and sleeve argon arc welding (such as Figure 3 b) Sleeve end plate structure), wherein the end plate thickness is 5mm and the sleeve thickness is 1.5mm. Since the argon arc welding temperature at the connection between the sleeve and the end plate is much higher than the melting temperature of the brazing material layer of the end plate (the brazing material layer of the end plate itself), the brazing quality of the heat dissipation pipe at the edge of the argon arc weld is affected. In addition, the strength of the argon arc weld at the connection between the sleeve and the end plate is weakened after trimming, resulting in the product pressure test pass rate of the aluminum alloy radiator being less than 60% during batch production. The end plate of the present invention is an integrated structure, and there is no need to weld the sleeve, which effectively avoids the above-mentioned technical problems. Then, under the premise of ensuring that the number of heat dissipation pipes arranged remains unchanged, the product pressure test pass rate reaches 100%.

[0031] In summary, the present invention has the advantages of high compactness, high pressure resistance and high reliability, and avoids the problem of stress concentration caused by multiple welding and the problem of medium leakage at the connection between the end plate and the shell. It is of great significance to the design of advanced lubricating oil systems for high power-to-weight ratio engines. The present invention can also be applied to the field of shell-and-tube heat exchangers in other systems such as aircraft hydraulic oil systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the end plate with the arc surface presenting a concave structure when the inner cavity of the tube is a high-pressure cavity;

[0033] Figure 2 It is a schematic diagram of the end plate with the arc surface presenting an outward convex structure when the inter-tube cavity is a high-pressure cavity;

[0034] Figure 3 It is a schematic diagram of a shell and tube heat exchanger;

[0035] Figure 4 for Figure 3 A partial enlarged view of the welding part of the shell-and-tube heat exchanger at position I in the middle;

[0036] Figure 5 Schematic diagrams of three traditional structural end plates; (a) is a flat end plate, (b) is a sleeve end plate, and (c) is a bent end plate;

[0037] Figure 6 The bending condition of the rear panel of a radiator after the pressure test.

[0038] Among them, 1-end plate, 2-connecting wall A, 3-heat dissipation pipe connecting hole, 4-arc surface, 5-brazing layer, 6-connecting wall B, 7-shell, 8-cover A, 9-heat dissipation pipe, 10-inter-tube cavity inlet, 11-inter-tube cavity outlet, 12-cover B, 13-tube inner cavity inlet, 14-tube inner cavity outlet, 15-inter-tube cavity, 16-tube inner cavity. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0040] Example 1. An end plate for a shell-and-tube heat exchanger, see Figure 1-Figure 6 The edge of the inner cavity end surface of the end plate 1 is surrounded by a connecting wall A2, and the end plate 1 is provided with heat pipe connecting holes 3. The inner cavity end surface of the end plate 1 is an inner concave / outer convex arc surface 4 structure; the inner and outer cavity end surfaces of the end plate 1 are both paved with a brazing layer 5, and the chamfer R between the connecting wall A2 and the inner cavity end surface of the end plate 1 is ≯0.5mm. Milling is used.

[0041] The edge of the outer cavity end surface of the end plate 1 is surrounded by a connecting wall B6, and the chamfer R between the connecting wall B6 and the inner cavity end surface of the end plate 1 is 0.5 mm. Milling is adopted.

[0042] The height of the connection wall B6 of the aforementioned end plate 1 is 10 to 15 mm.

[0043] The aforementioned end plate manufacturing method comprises the following steps:

[0044] S1. A connecting wall A2 is machined on the inner surface of the end plate 1;

[0045] S2. A curved surface 4 is machined on the inner surface of the end plate 1 in the connecting wall A2;

[0046] S3. Laying a brazing layer 5 on the curved surface 4;

[0047] S4. Make a heat dissipation pipe connection hole 3 on the end plate 1.

[0048] In step S1 , a connection wall A2 is processed on the inner cavity end surface of the end plate 1 , and a connection wall B6 is processed on the outer cavity end surface of the end plate 1 .

[0049] In step S3 , while laying the brazing layer 5 on the arc surface 4 , the brazing layer 5 is also laid on the outer cavity end surface of the end plate 1 .

[0050] In step S3 , after the brazing layer 5 is laid, heating is performed to allow the brazing layer 5 to adhere to the end plate 1 .

[0051] The shell-and-tube heat exchanger made of the above-mentioned end plates includes a shell 7, and the two ends of the shell 7 are respectively connected to the cover A8 and the cover B12 through the end plate 1; a heat dissipation tube 9 is fixed between the two end plates 1 through the heat dissipation tube connection hole 3; the shell 7 is provided with an inter-tube cavity inlet 10 and an inter-tube cavity outlet 11, and the covers A and B are respectively provided with a tube cavity inlet 13 and a tube cavity outlet 14.

[0052] When the inter-tube cavity 15 is a high-pressure cavity, the arcuate surface 4 is an outward convex structure, and when the inner tube cavity 16 is a high-pressure cavity, the arcuate surface 4 is an inward concave structure.

[0053] The cover A, B are respectively connected to the end faces of the corresponding connecting wall B6 by fusion welding.

[0054] The inner wall of the connecting wall A2 is connected to the shell 7 by brazing, and the end surface of the connecting wall A2 is also connected to the shell 7 by fusion welding.

[0055] The aforementioned heat dissipation pipe 9 protrudes from the outer cavity end surface of the end plate 1 .

Claims

1. An end plate for a shell-and-tube heat exchanger, characterized in that: The edge of the inner cavity end surface of the end plate (1) is surrounded by a connecting wall A (2), the end plate (1) is provided with heat dissipation pipe connecting holes (3), and the inner cavity end surface of the end plate (1) presents an inwardly concave / outwardly convex arc surface (4) structure; the inner and outer cavity end surfaces of the end plate (1) are both paved with a brazing layer (5), and the chamfer R between the connecting wall A (2) and the inner cavity end surface of the end plate (1) is ≯0.5 mm.

2. The end plate for a shell-and-tube heat exchanger according to claim 1, characterized in that: The edge of the outer cavity end surface of the end plate (1) is surrounded by a connecting wall B (6), and the chamfer R between the connecting wall B (6) and the inner cavity end surface of the end plate (1) is 0.5 mm.

3. The end plate for a shell-and-tube heat exchanger according to claim 2, characterized in that: The height of the connecting wall B (6) of the end plate (1) is 10 to 15 mm.

4. A method for manufacturing an end plate according to any one of claims 1 to 3, characterized in that: The steps include: S1. A connecting wall A (2) is machined on the inner end surface of the end plate (1); S2. A curved surface (4) is machined on the inner end surface of the end plate (1) in the connecting wall A (2); S3. Laying a brazing layer (5) on the curved surface (4); S4. Form a heat dissipation pipe connection hole (3) on the end plate (1).

5. The method for manufacturing an end plate according to claim 4, characterized in that: In step S1, a connecting wall A (2) is machined on the inner cavity end surface of the end plate (1), and a connecting wall B (6) is machined on the outer cavity end surface of the end plate (1).

6. The method for manufacturing an end plate according to claim 4, characterized in that: In step S3, while laying the brazing layer (5) on the arc surface (4), the brazing layer (5) is also laid on the outer cavity end surface of the end plate (1).

7. The method for manufacturing an end plate according to claim 4, characterized in that: In step S3, after the brazing layer (5) is laid, heating is performed to allow the brazing layer (5) to adhere to the end plate (1).

8. A shell-and-tube heat exchanger made of the end plate according to any one of claims 1 to 3, characterized in that: The invention comprises a shell (7), wherein two ends of the shell (7) are respectively connected to a cover A (8) and a cover B (12) via end plates (1); a heat dissipation pipe (9) is fixed between the two end plates (1) via a heat dissipation pipe connection hole (3); the shell (7) is provided with an inter-tube cavity inlet (10) and an inter-tube cavity outlet (11), and the covers A and B are respectively provided with a tube inner cavity inlet (13) and a tube inner cavity outlet (14).

9. The shell and tube heat exchanger according to claim 8, characterized in that: When the inter-tube cavity (15) is a high-pressure cavity, the arcuate surface (4) is an outward convex structure, and when the inner tube cavity (16) is a high-pressure cavity, the arcuate surface (4) is an inward concave structure.

10. The shell and tube heat exchanger according to claim 8, characterized in that: The sealing covers A and B are respectively connected to the end surfaces of the corresponding connecting walls B (6) by fusion welding.

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