Tube bundle type heat exchanger

Abstract

The invention provides a tube bundle type heat exchanger, and belongs to the technical field of tube bundle type heat exchanger design, the tube bundle type heat exchanger comprises a barrel, a tube plate, a plurality of heat exchange tubes and a plurality of supports, and the barrel is provided with a plurality of expansion joints; a protective sleeve is arranged between one end of each heat exchange tube in the gas inlet direction and the tube plate, one end of each protective sleeve is inserted into the corresponding heat exchange tube, a gap is formed between each protective sleeve and the corresponding heat exchange tube to form a heat insulation gas film, and the other end of each protective sleeve is fixedly connected with one side of the tube plate; at least one support comprises a first sliding base plate and a second sliding base plate, and the first sliding base plate and the second sliding base plate are arranged on the two sides of a saddle base plate of the support and connected with the saddle base plate and a civil foundation through fasteners. Kidney-shaped holes used for releasing strain are formed in the first sliding base plate, the saddle bottom plate and the second sliding base plate; and the thermal strain of the tube bundle type heat exchanger in the working process is fully released.

Description

Technical Field

[0001] The invention belongs to the technical field of tube bundle heat exchanger design, and particularly relates to a tube bundle heat exchanger. Background Art

[0002] During high-altitude simulation tests of liquid attitude control rocket engines, the high-temperature, high-velocity, and corrosive gas must first be pressurized and cooled. A jet pump then draws the gas into the atmosphere and discharges it. Due to constraints on gas flow losses, heat transfer efficiency, and cooling water flow, the bundled tube heat exchanger used in these tests typically utilizes a cooling scheme where the high-temperature gas flows through the tubes and the cooling water flows through the shell.

[0003] During high-altitude simulation tests of liquid attitude control rocket engines, the heat load on the gas is greatest at the welds between the heat exchange tubes and the windward tube sheet. This creates a significant temperature gradient within the tubes, potentially creating significant thermal stress between the tubes and the tube sheet, potentially damaging the weld structure. Furthermore, because the bundled heat exchanger used in these high-altitude simulation tests is approximately 10 meters long and 4 meters in diameter, the entire tube will deform by 2-3 cm during operation. This significant strain has led to the failure of the high-altitude simulation test. Summary of the Invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a tube bundle heat exchanger, including a cylinder, a tube sheet, a plurality of heat exchange tubes and a plurality of supports, wherein the cylinder is provided with a plurality of expansion joints; the plurality of heat exchange tubes are all located at one end of the gas inlet direction; a protective sleeve is provided between each heat exchange tube and the tube sheet, and one end of each protective sleeve is inserted into the interior of the heat exchange tube, and a preset gap is set between the protective sleeve and the heat exchange tube, and the gap forms a heat-insulating gas film; the other end of each protective sleeve is fixedly connected to one side of the tube sheet.

[0005] Multiple supports are fixedly connected to the cylinder, wherein at least one support includes a first sliding pad and a second sliding pad; the first sliding pad and the second sliding pad are arranged on both sides of the saddle base plate of the corresponding support in the vertical direction, and the first sliding pad and the second sliding pad are connected to the saddle base plate and the civil engineering foundation through fasteners; the first sliding pad, the saddle base plate and the second sliding pad are all provided with waist-shaped holes for releasing strain.

[0006] Preferably, the protective sleeve is made of S31008 high-temperature resistant stainless steel.

[0007] Preferably, the protective sleeve includes a first sleeve and a second sleeve; the outer diameter of the second sleeve is smaller than the outer diameter of the first sleeve; the inner diameter of the second sleeve is equal to the inner diameter of the first sleeve; the second sleeve is inserted into the interior of the heat exchange tube; one end of the first sleeve is connected to the tube sheet, and the other end of the first sleeve is connected to one end of the second sleeve; a preset gap is provided between the end surface where the first sleeve is connected to the second sleeve and the end surface of the heat exchange tube, and a preset gap is provided between the outer wall of the second sleeve and the inner wall of the heat exchange tube, and the gap forms a heat-insulating air film.

[0008] Preferably, one end of the first sleeve is connected to the tube sheet, and the connected end surface is coated with a chromium oxide high-temperature resistant coating with a thickness of 0.3-0.4 mm.

[0009] Preferably, one end of the first sleeve is connected to the tube sheet by V-shaped welding.

[0010] Preferably, the fasteners include anchor bolts and nuts; the first sliding pad, the saddle bottom plate, the second sliding pad and the embedded steel plate are connected by the anchor bolts and nuts.

[0011] Preferably, the cross-section of each expansion joint is arc-shaped.

[0012] Preferably, the preload force T of the anchor bolt is determined by the following formula: ; Where M is the tightening torque of the anchor bolt, μ is the friction coefficient of the anchor bolt, and D is the nominal diameter of the anchor bolt.

[0013] The tube bundle heat exchanger provided by the present invention has the following beneficial effects: By inserting a protective sleeve into the heat exchange tube, the present invention can form an insulating gas film between the heat exchange tube and the tube sheet weld, reduce the heat transfer coefficient between the gas and the weld, and protect the weld; by arranging one or more expansion joints on the cylinder of the tube bundle heat exchanger, it can compensate for the thermal strain generated by the tube bundle heat exchanger during operation; by arranging a first sliding pad and a second sliding pad on both sides of the saddle base plate of at least one support, it can reduce the friction between the saddle base plate and the civil foundation, facilitate the rapid release of thermal stress, reduce the deformation of the cylinder, and successfully simulate the high-altitude test of the liquid attitude control rocket engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] To more clearly illustrate the embodiments of the present invention and its design, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0015] Figure 1 This is a structural diagram of a tube bundle heat exchanger according to an embodiment of the present invention; Figure 2 This is a structural diagram of a sliding support according to an embodiment of the present invention; Figure 3 This is a structural diagram of a protective sleeve according to an embodiment of the present invention.

[0016] Description of reference numerals: 1-cylinder; 2-tube sheet; 3-heat exchange tube; 4-support; 5-expansion joint; 6-protective sleeve; 7-insulating air film; 8-anchor bolt; 9-nut; 10-embedded steel plate; 41-first sliding pad; 42-second sliding pad; 43-saddle base plate; 44-waist-shaped hole; 61-first sleeve; 62-second sleeve. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solution of the present invention and to be able to implement it, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention.

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the technical solutions of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0019] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0020] Example The present invention provides a tube bundle heat exchanger, specifically Figure 1As shown, it comprises a cylinder 1, multiple tube sheets 2, multiple heat exchange tubes 3, and multiple supports 4. Multiple expansion joints 5 are provided on the cylinder 1; a protective sleeve 6 is provided between the end of each heat exchange tube 3 located in the gas inlet direction and the tube sheet 2. One end of each protective sleeve 6 is inserted into the interior of the heat exchange tube 3, with a gap provided between the heat exchange tube 3 to form a thermal insulation film 7. The other end of each protective sleeve 6 is fixedly connected to one side of the tube sheet 2.

[0021] Multiple supports 4 are fixedly connected to the cylinder 1, wherein at least one support 4 includes a first sliding pad 41 and a second sliding pad 42; Figure 2 The left and right directions are horizontal reference directions, and the first sliding pad 41 and the second sliding pad 42 are respectively arranged on the upper and lower sides of the horizontal plane of the saddle base plate 43 of the corresponding support 4; the first sliding pad 41 and the second sliding pad 42 are connected to the saddle base plate 43 and the civil foundation through fasteners; the first sliding pad 41, the saddle base plate 43 and the second sliding pad 42 are all provided with a waist-shaped hole 44 for releasing strain, and the length direction of the waist-shaped hole 44 is the same as the length direction of the cylinder 1.

[0022] Normally, the maximum working temperature of the heat exchange tube 3 is T t , the ambient temperature is T0, and the thermal expansion coefficient of the heat exchange tube 3 is , the length of the heat exchange tube 3 is L, then the limit thermal deformation ΔL of the heat exchange tube 3 during the use of the tube bundle heat exchanger is given by the following formula: ; If the deformation cannot be released, a tensile force F will be generated in the heat exchange tube 3 and the cylinder 1, and huge heat exchange tube thermal stress will be generated in the heat exchange tube 3 and the cylinder 1 respectively. and thermal stress of the cylinder ; Tensile force F, thermal stress of heat exchange tube and thermal stress of the cylinder Determined by the following formula: ; ; ; Where, is the thermal expansion coefficient of the heat pipe 3, T t is the maximum temperature of the heat exchange tube 3 when it is working, T0 is the ambient temperature, d o is the outer diameter of the heat exchange tube 3, d i is the inner diameter of the heat exchange tube 3, n is the number of heat exchange tubes 3, E is the elastic modulus of the heat exchange tube 3, D o is the outer diameter of the cylinder 1, D iis the inner diameter of the cylinder 1.

[0023] To meet the requirements for safe use of the equipment, the following formula must be met: ; ; Where, is the thermal stress of heat exchange tube 3, [ ] is the allowable stress of the heat exchange tube 3; is the thermal stress of cylinder 1, ] is the allowable stress of cylinder 1.

[0024] For tube bundle heat exchangers used in general environments, the above requirements can be met; however, for tube bundle heat exchangers used in high-altitude simulation tests of liquid attitude control rocket engines, the temperature gradient generated in the working and non-working states is huge. ℃, making it difficult to meet the above requirements. In order to meet the structural strength requirements of the equipment, one or more expansion joints 5 are set on the cylinder 1 to compensate for the huge strain generated by the tube bundle heat exchanger for the high-altitude simulation test of the liquid attitude control rocket engine during operation. The total compensation amount of the expansion joint 5 should be greater than the total deformation of the heat exchange tube 3.

[0025] Furthermore, in order to quickly release the thermal deformation formed during the operation of the tube bundle heat exchanger used in the high-altitude simulation test of the liquid attitude control rocket engine, it is necessary to avoid over-constraint of the tube bundle heat exchanger during installation. Therefore, the present invention provides at least one support 4, which includes a first sliding pad 41 and a second sliding pad 42; Figure 2 The left and right directions are horizontal reference directions. A first sliding pad 41 and a second sliding pad 42 are respectively provided on the upper and lower sides of the horizontal plane of the saddle base plate 43 of the corresponding support 4. The first sliding pad 41 and the second sliding pad 42 are connected to the saddle base plate 43 and the civil engineering foundation through fasteners. The fasteners include anchor bolts 8 and matching nuts 9. The saddle base plate 43 is the lowest plate of the support 4. Figure 2 As shown, the first sliding plate 41, the saddle base plate 43, the second sliding plate 42 and the embedded steel plate 10 are connected by the anchor bolts 8 and nuts 9. The pre-tightening force of the anchor bolts 8 It is determined by the following formula: ; Wherein, M is the tightening torque of the anchor bolt 8, μ is the friction coefficient of the anchor bolt 8, and D is the nominal diameter of the anchor bolt 8.

[0026] The weight G of the tube bundle heat exchanger is considered to be evenly distributed. Each tube bundle heat exchanger is fixed with N1 fixed supports (excluding the supports of the first sliding pad 41 and the second sliding pad 42) and sliding supports (including the first sliding pad 41 and the second sliding pad 42). Anchor bolts 8. The friction between the first sliding pad 41 and the saddle bottom plate 43 , the friction between the second sliding pad 42 and the saddle bottom plate 43 Determined by the following formula: ; ; Where, is the friction coefficient between the first sliding pad 41 and the saddle bottom plate 43, is the friction coefficient between the second sliding pad 42 and the saddle bottom plate 43, is the pre-tightening force of the anchor bolt 8, G is the weight of the tube bundle heat exchanger, is the number of fixed supports and sliding supports, is the number of anchor bolts 8 used in the sliding bearing.

[0027] In order to release the thermal stress, the friction force f1, f2 and the tensile force It refers to the horizontal tensile force generated by the thermal deformation of the heat exchange tube 3. The deformation of the heat exchange tube 3 drives the deformation of the cylinder 1, and the deformation of the cylinder 1 drives the deformation of the support. Specifically, the following relationship should be satisfied: ; During the design process, existing bundled heat exchangers used in high-altitude simulation tests of liquid attitude control rocket engines typically have the saddle base plate 43 directly fixed to the civil engineering foundation. This prevents the release of thermal stress generated during operation, leading to significant deformation of the bundled heat exchanger and failure to meet operational requirements. In the present invention, both the first sliding pad 41 and the second sliding pad 42 are made of a smooth material such as polytetrafluoroethylene (PTFE). When thermal stress is generated during operation, the coefficient of friction between the first sliding pad 41, the saddle base plate 43, and the second sliding pad 42 decreases horizontally from 0.1 to 0.01, reducing friction between the bundled heat exchanger's sliding support and the civil engineering foundation. The first sliding plate 41 with the waist-shaped hole 44, the saddle base plate 43 and the second sliding plate 42 can move in the horizontal direction, thereby releasing thermal strain and reducing the deformation of the tube bundle heat exchanger, so that the tube bundle heat exchanger meets the use requirements.

[0028] Furthermore, a plurality of through holes are provided on the tube sheet 2, one end of each heat exchange tube 3 is inserted into a through hole, and the end surface of the heat exchange tube 3 inserted into the through hole is welded to the tube sheet 2 by argon arc welding or other methods. During the operation of the bundle heat exchanger used in the high-altitude simulation test of the liquid attitude control rocket engine, the total temperature of the gas can reach up to about 1000°C after initial cooling and pressurization. The gas may form a local stagnant flow area near the weld between the heat exchange tube 3 and the tube sheet 2, making the gas temperature in this area close to 1000°C. In order to reduce the influence of the high-temperature gas on the weld between the heat exchange tube 3 and the tube sheet 2, the present invention sets a protective sleeve 6 near the weld, such as Figure 3 As shown, the protective sleeve 6 includes a first sleeve 61 and a second sleeve 62. The outer diameter of the second sleeve 62 is smaller than the outer diameter of the first sleeve 61, and the inner diameter of the second sleeve 62 is equal to the inner diameter of the first sleeve 61. The second sleeve 62 is inserted into the interior of the heat exchange tube 3; one end of the first sleeve 61 is connected to the tube sheet 2, and the other end is connected to one end of the second sleeve 62; a preset gap is set between the end surface where the first sleeve 61 and the second sleeve 62 are connected and the end surface of the heat exchange tube 3, and a preset gap is set between the outer wall of the second sleeve 62 and the inner wall of the heat exchange tube 3. The gap forms a heat-insulating gas film 7. The protective sleeve 6 and the heat-insulating gas film 7 can reduce the heat transfer effect of high-temperature gas on the weld, thereby effectively protecting the weld between the heat exchange tube 3 and the tube sheet 2.

[0029] In this embodiment, before welding the heat exchange tube 3 and the tube sheet 2, it is necessary to remove oil, water, stains, oxide scale, etc. near the groove of the heat exchange tube 3, and then weld the heat exchange tube 3 and the tube sheet 2 at the groove. After welding is completed, the second sleeve 62 of the protective sleeve 6 is inserted into the heat exchange tube 3, and then one end of the first sleeve 61 of the protective sleeve 6 is welded to the tube sheet 2 using a V-weld. The material of the protective sleeve 6 can be selected from high-temperature resistant stainless steel such as S31008, which has good high-temperature resistance. In order to reduce the flow loss of high-speed gas in the tube bundle heat exchanger, the inlet of the protective sleeve 6 is chamfered. The pressure loss coefficient ζ near the protective sleeve 6 before chamfering is given by the following formula: ; Where, d i is the inner diameter of the heat exchange tube 3, D o is the outer diameter of the cylinder 1 , and n is the number of heat exchange tubes 3 .

[0030] After chamfering, the gas flow hardly escapes the wall surface, and the pressure loss coefficient can be reduced to about 0.05. By properly setting the dimensions of the tube sheet 2, heat exchange tube 3, and protective sleeve 6, an air film insulation layer can be formed between the weld of the protective sleeve 6 and the heat exchange tube 3.

[0031] In summary, the tube bundle heat exchanger of the present invention can compensate for the thermal strain generated by the tube bundle heat exchanger during operation by arranging one or more expansion joints 5 on the cylinder 1; the installation method combining fixed supports and sliding supports can reduce the friction between the supports and the civil foundation, thereby facilitating the rapid release of thermal stress; by inserting a protective sleeve 6 into the heat exchange tube 3, an insulating gas film 7 can be formed between the weld of the heat exchange tube 3 and the protective sleeve 6, thereby reducing the heat transfer coefficient between the gas and the weld and protecting the weld.

[0032] Compared with the prior art, the present invention has the following technical effects: 1. By setting one or more expansion joints 5 on the cylinder 1 of the tube bundle heat exchanger, the effective total deformation of the expansion joints 5 should be greater than the thermal deformation during operation of the tube bundle heat exchanger; the tube bundle heat exchanger adopts an installation method that combines fixed supports and sliding supports to reduce the friction between the sliding supports and the civil foundation. The effective sliding distance of the sliding supports is greater than the thermal deformation during operation of the tube bundle heat exchanger, which can fully release the thermal strain of the tube bundle heat exchanger during operation.

[0033] 2. A protective sleeve 6 is installed at the weld between the heat exchange tube 3 and the tube sheet 2 for active protection. This prevents direct contact between the high-temperature gas and the weld between the heat exchange tube 3 and the tube sheet 2. A heat-insulating gas film 7 is formed between the welds, further reducing the heat transfer effect of the high-temperature gas on the welds. A chromium oxide high-temperature resistant coating is sprayed on the windward side of the tube sheet 2, the end face of the protective sleeve 6, and the interior, further enhancing the high-temperature resistance of the tube bundle heat exchanger's welds.

[0034] The above embodiments are only preferred specific implementation methods of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention fall within the protection scope of the present invention.

Claims

1. A tube bundle heat exchanger, comprising a cylinder (1), a tube sheet (2), a plurality of heat exchange tubes (3) and a plurality of supports (4), characterized in that: The tube bundle heat exchanger is applied to a high-altitude simulation test system for a liquid attitude control rocket engine; a plurality of expansion joints (5) are provided on the cylinder (1); a plurality of heat exchange tubes (3) are all located at one end in the direction of gas inlet; a protective sleeve (6) is provided between each heat exchange tube (3) and the tube sheet (2), and one end of each protective sleeve (6) is inserted into the interior of the heat exchange tube (3), and a preset gap is formed between the protective sleeve and the heat exchange tube (3), wherein the gap forms a heat insulating gas film (7); the other end of each protective sleeve (6) is fixedly connected to one side of the tube sheet (2); A plurality of the supports (4) are fixedly connected to the cylinder (1), wherein at least one support (4) comprises a first sliding pad (41) and a second sliding pad (42); the first sliding pad (41) and the second sliding pad (42) are arranged on both sides of a saddle base plate (43) of the corresponding support (4) in a vertical direction, and the first sliding pad (41) and the second sliding pad (42) are connected to the saddle base plate (43) and the civil engineering foundation through fasteners; the first sliding pad (41), the saddle base plate (43) and the second sliding pad (42) are all provided with waist-shaped holes (44) for releasing strain.

2. The tube bundle heat exchanger according to claim 1, characterized in that The protective sleeve (6) is made of S31008 high-temperature resistant stainless steel.

3. The tube bundle heat exchanger according to claim 1, characterized in that The protective sleeve (6) includes a first sleeve (61) and a second sleeve (62); the outer diameter of the second sleeve (62) is smaller than the outer diameter of the first sleeve (61); the inner diameter of the second sleeve (62) is equal to the inner diameter of the first sleeve (61); the second sleeve (62) is inserted into the interior of the heat exchange tube (3); one end of the first sleeve (61) is connected to the tube sheet (2), and the other end of the first sleeve (61) is connected to one end of the second sleeve (62); a preset gap is provided between the end surface where the first sleeve (61) and the second sleeve (62) are connected and the end surface of the heat exchange tube (3), and a preset gap is provided between the outer wall of the second sleeve (62) and the inner wall of the heat exchange tube (3), and the gap forms a heat-insulating gas film (7).

4. The tube bundle heat exchanger according to claim 3, characterized in that One end of the first sleeve (61) is connected to the tube sheet (2), and the connected end surface is coated with a chromium oxide high-temperature resistant coating with a thickness of 0.3-0.4 mm.

5. The tube bundle heat exchanger according to claim 3, characterized in that One end of the first sleeve (61) is connected to the tube plate (2) by V-shaped welding.

6. The tube bundle heat exchanger according to claim 1, characterized in that The fasteners include anchor bolts (8) and nuts (9); the first sliding pad (41), the saddle base plate (43), the second sliding pad (42) and the embedded steel plate (10) are connected via the anchor bolts (8) and nuts (9).

7. The tube bundle heat exchanger according to claim 1, characterized in that The cross section of each expansion joint (5) is in the shape of an arc.

8. The tube bundle heat exchanger according to claim 6, characterized in that The preload force T of the anchor bolt (8) is determined by the following formula: ； Wherein, M is the tightening torque of the anchor bolt (8), μ is the friction coefficient of the anchor bolt (8), and D is the nominal diameter of the anchor bolt (8).

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